Revista CD Expert 8/Revista CD Expert nº 08 CD1.iso/Utilitarios/Programacao/MS-DOS Interrupt List/inter60d/PORTS.A

Text File | 1999-01-03 | 335.3 KB | 9,700 lines

PORTS LIST            Release 60        Last change 03jan99
Copyright (c) 1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999 Ralf Brown
[This file originally by Wim Osterholt <[e-mail]>,
 though it has grown considerably since.]

        XT, AT and PS/2     I/O port addresses

Do NOT consider this information to be complete and accurate.  If you want
to do hardware programming ALWAYS check the appropriate data sheets (but
even they are sometimes in error!).  Be aware that erroneous port programming
can put your data or even your hardware at risk.

There are a number of memory-mapped addresses in use for I/O; see MEMORY.LST
for details on memory-mapped I/O.

--------!---Note-----------------------------
Note: the port description format is:

PPPPw RW  description

where:    PPPP    is the four-digit hex port number or a plus sign and three hex
        digits to indicate an offset from a base port address
    w    is blank for byte-size port, 'w' for word, and 'd' for dword
    R    is dash (or blank) if not readable, 'r' if sometimes readable,
        'R' if "always" readable, '?' if readability unknown
    W    is dash (or blank) if not writable, 'w' if sometimes writable,
        'W' if "always" writable, 'C' if write-clear, and
        '?' if writability unknown
----------P0000001F--------------------------
PORT 0000-001F - DMA 1 - FIRST DIRECT MEMORY ACCESS CONTROLLER (8237)
SeeAlso: PORT 0080h-008Fh"DMA",PORT 00C0h-00DFh

0000  R-  DMA channel 0    current address        byte  0, then byte 1
0000  -W  DMA channel 0    base address        byte  0, then byte 1
0001  RW  DMA channel 0 word count        byte 0, then byte 1
0002  R-  DMA channel 1    current address        byte  0, then byte 1
0002  -W  DMA channel 1    base address        byte  0, then byte 1
0003  RW  DMA channel 1 word count        byte 0, then byte 1
0004  R-  DMA channel 2    current address        byte  0, then byte 1
0004  -W  DMA channel 2    base address        byte  0, then byte 1
0005  RW  DMA channel 2 word count        byte 0, then byte 1
0006  R-  DMA channel 3    current address        byte  0, then byte 1
0006  -W  DMA channel 3    base address        byte  0, then byte 1
0007  RW  DMA channel 3 word count        byte 0, then byte 1

0008  R-  DMA channel 0-3 status register (see #P0001)
0008  -W  DMA channel 0-3 command register (see #P0002)
0009  -W  DMA channel 0-3 write request register (see #P0003)
000A  RW  DMA channel 0-3 mask register (see #P0004)
000B  -W  DMA channel 0-3 mode register (see #P0005)

000C  -W  DMA channel 0-3 clear byte pointer flip-flop register
      any write clears LSB/MSB flip-flop of address and counter registers
000D  R-  DMA channel 0-3 temporary register
000D  -W  DMA channel 0-3 master clear register
      any write causes reset of 8237
000E  -W  DMA channel 0-3 clear mask register
      any write clears masks for all channels
000F  rW  DMA channel 0-3 write mask register (see #P0006)
Notes:    the temporary register is used as holding register in memory-to-memory
      DMA transfers; it holds the last transferred byte
    channel 2 is used by the floppy disk controller
    on the IBM PC/XT channel 0 was used for the memory refresh and
      channel 3 was used by the hard disk controller
    on AT and later machines with two DMA controllers, channel 4 is used
      as a cascade for channels 0-3
    command and request registers do not exist on a PS/2 DMA controller

Bitfields for DMA channel 0-3 status register:
Bit(s)    Description    (Table P0001)
 7    channel 3 request active
 6    channel 2 request active
 5    channel 1 request active
 4    channel 0 request active
 3    channel terminal count on channel 3
 2    channel terminal count on channel 2
 1    channel terminal count on channel 1
 0    channel terminal count on channel 0
SeeAlso: #P0002,#P0481

Bitfields for DMA channel 0-3 command register:
Bit(s)    Description    (Table P0002)
 7    DACK sense active high
 6    DREQ sense active high
 5    =1 extended write selection
    =0 late write selection
 4    rotating priority instead of fixed priority
 3    compressed timing (two clocks instead of four per transfer)
    =1 normal timing (default)
    =0 compressed timing
 2    =1 enable controller
    =0 enable memory-to-memory
 1-0    channel number
SeeAlso: #P0001,#P0004,#P0005,#P0482

Bitfields for DMA channel 0-3 request register:
Bit(s)    Description    (Table P0003)
 7-3    reserved (0)
 2    =0 clear request bit
    =1 set request bit
 1-0    channel number
    00 channel 0 select
    01 channel 1 select
    10 channel 2 select
    11 channel 3 select
SeeAlso: #P0004

Bitfields for DMA channel 0-3 mask register:
Bit(s)    Description    (Table P0004)
 7-3    reserved (0)
 2    =0 clear mask bit
    =1 set mask bit
 1-0    channel number
    00 channel 0 select
    01 channel 1 select
    10 channel 2 select
    11 channel 3 select
SeeAlso: #P0001,#P0002,#P0003,#P0484

Bitfields for DMA channel 0-3 mode register:
Bit(s)    Description    (Table P0005)
 7-6    transfer mode
    00 demand mode
    01 single mode
    10 block mode
    11 cascade mode
 5    direction
    =0 increment address after each transfer
    =1 decrement address
 3-2    operation
    00 verify operation
    01 write to memory
    10 read from memory
    11 reserved
 1-0    channel number
    00 channel 0 select
    01 channel 1 select
    10 channel 2 select
    11 channel 3 select
SeeAlso: #P0002,#P0485

Bitfields for DMA channel 0-3 write mask register:
Bit(s)    Description    (Table P0006)
 7-4    reserved
 3    channel 3 mask bit
 2    channel 2 mask bit
 1    channel 1 mask bit
 0    channel 0 mask bit
Note:    each mask bit is automatically set when the corresponding channel
      reaches terminal count or an extenal EOP sigmal is received
SeeAlso: #P0004,#P0486
----------P0010001F--------------------------
PORT 0010-001F - DMA CONTROLLER (8237) ON PS/2 MODEL 60 & 80
SeeAlso: PORT 0000h-001Fh,PORT 0080h-008Fh"DMA",PORT 00C0h-00DFh

0018  -W  extended function register (see #P0007)
001A  -W  extended function execute register

Bitfields for DMA extended function register:
Bit(s)    Description    (Table P0007)
 7-4    function code (see #P0008)
 3    reserved (0)
 2-0    channel number
    000 channel 0 select
    001 channel 1 select
    010 channel 2 select
    011 channel 3 select
    100 channel 4 select
    101 channel 5 select
    110 channel 6 select
    111 channel 7 select

(Table P0008)
Values for DMA extended function codes (data go to/from PORT 001Ah):
Value    Description          Parameters  Results
 00h    current address register      -          CA0,CA1
 02h    write address              -          A0,A1,P
 03h    read  address           A0,A1,P     -
 04h    write word count register   C0,C1     -
 05h    read  word count register     -           C0,C1
 06h    read status register          -         S
 07h    mode register              -         M
 09h    mask channel              -         -
 0Ah    unmask channel              -         -
 0Dh    master clear              -         -
Note:    CA0/CA1      LSB/MSB of the current address register
    A0/A1      LSB/MSB of the base address register
    P      DMA page address
    C0/C1      LSB/MSB of the word count register
    S      status register value (see #P0001, #P0481)
    M      mode register value (see #P0005, #P0485)
    first, the extended function register is written, then the extended
      function register execute register is read/written if the function
      being executing requires

Bitfields for DMA extended mode register:
Bit(s)    Description    (Table P0009)
 7    reserved (0)
 6    =0 8-bit transfer
    =1 16-bit transfer
 5-4    reserved (0)
 3    transfer type
    =0 read from memory
    =1 write to memory
 2    =0 disable memory write
    =1 enable  memory write
 1    reserved (0)
 0    address select
    =0 use 0 as base address
    =1 use a value from base address register
Note:    the IBM PS/2 model 80 technical reference doesn't seem to mention this
      register's address
----------P0020003F--------------------------
PORT 0020-003F - PIC 1 - PROGRAMMABLE INTERRUPT CONTROLLER (8259A)
SeeAlso: PORT 00A0h-00AFh"PIC 2",INT 08"IRQ0",INT 0F"IRQ7"

0020  -W  PIC initialization command word ICW1 (see #P0010)
0020  -W  PIC output control word OCW2 (see #P0015)
0020  -W  PIC output control word OCW3 (see #P0016)
0020  R-  PIC  interrupt request/in-service registers after OCW3
        request register:
         bit 7-0 = 0  no active request for the corresponding int. line
             = 1  active request for corresponding interrupt line
        in-service register:
         bit 7-0 = 0  corresponding line not currently being serviced
             = 1  corresponding int. line currently being serviced

0021  -W  PIC ICW2,ICW3,ICW4 immed after ICW1 to 0020 (see #P0011,#P0012,#P0013)
0021  RW  PIC master interrupt mask register OCW1 (see #P0014)

Bitfields for PIC initialization command word ICW1:
Bit(s)    Description    (Table P0010)
 7-5    0 (only used in 8080/8085 mode)
 4    ICW1 is being issued
 3    (LTIM)
    =0  edge triggered mode
    =1  level triggered mode
 2    interrupt vector size
    =0 successive interrupt vectors use 8 bytes (8080/8085)
    =1 successive interrupt vectors use 4 bytes (80x86)
 1    (SNGL)
    =0  cascade mode
    =1  single mode, no ICW3 needed
 0    ICW4 needed
SeeAlso: #P0011,#P0012,#P0013

Bitfields for PIC initialization command word ICW2:
Bit(s)    Description    (Table P0011)
 7-3    address lines A0-A3 of base vector address for PIC
 2-0    reserved
SeeAlso: #P0010,#P0012,#P0013

Bitfields for PIC initialization command word ICW3:
Bit(s)    Description    (Table P0012)
 7-0    =0 slave controller not attached to corresponding interrupt pin
    =1 slave controller attached to corresponding interrupt pin
SeeAlso: #P0010,#P0011,#P0013

Bitfields for PIC initialization command word ICW4:
Bit(s)    Description    (Table P0013)
 7-5    reserved (0)
 4    running in special fully-nested mode
 3-2    mode
    0x nonbuffered mode
    10 buffered mode/slave
    11 buffered mode/master
 1    Auto EOI
 0    =0  8085 mode
    =1  8086/8088 mode
SeeAlso: #P0010,#P0011,#P0012

Bitfields for PIC output control word OCW1:
Bit(s)    Description    (Table P0014)
 7    disable IRQ7 (parallel printer interrupt)
 6    disable IRQ6 (diskette interrupt)
 5    disable IRQ5 (fixed disk interrupt)
 4    disable IRQ4 (serial port 1 interrupt)
 3    disable IRQ3 (serial port 2 interrupt)
 2    disable IRQ2 (video interrupt)
 1    disable IRQ1 (keyboard, mouse, RTC interrupt)
 0    disable IRQ0 (timer interrupt)
SeeAlso: #P0015,#P0016,#P0418

Bitfields for PIC output control word OCW2:
Bit(s)    Description    (Table P0015)
 7-5    operation
    000 rotate in auto EOI mode (clear)
    001 (WORD_A) nonspecific EOI
    010 (WORD_H) no operation
    011 (WORD_B) specific EOI
    100 (WORD_F) rotate in auto EOI mode (set)
    101 (WORD_C) rotate on nonspecific EOI command
    110 (WORD_E) set priority command
    111 (WORD_D) rotate on specific EOI command
 4-3    reserved (00 - signals OCW2)
 2-0    interrupt request to which the command applies
    (only used by WORD_B, WORD_D, and WORD_E)
SeeAlso: #P0014,#P0016

Bitfields for PIC output control word OCW3:
Bit(s)    Description    (Table P0016)
 7    reserved (0)
 6-5    special mask
    0x  no operation
    10  reset special mask
    11  set special mask mode
 4-3    reserved (01 - signals OCW3)
 2    poll command
 1-0    function
    0x  no operation
    10  read interrupt request register on next read from PORT 0020h
    11  read interrupt in-service register on next read from PORT 0020h
Note:    the special mask mode permits all other interrupts (even those with
      lower priority) to be processed while an interrupt is already in
      service, but will not re-issue an interrupt for a particular IRQ
      while it remains in service
SeeAlso: #P0014,#P0015
----------P0022------------------------------
PORT 0022 - Intel 82439TX Chipset - Power Control register
SeeAlso: PORT 0022h"82443BX"

0022  RW  PM2 Register Block
    bits 7-1: reserved
    bit 0:    Arbiter Disable
--------p-P0022------------------------------
PORT 0022 - Intel 82443BX - "PM2_CTL" ACPI Power Control 2 Register
SeeAlso: PORT 0022h"82439TX",#01142 at INT 1A/AX=B10Ah/SF=8086h

0022  RW  ACPI Power Control Register 2
    bits 7-1: reserved
    bit 0:    disable primary PCI and AGP arbiter requests
----------P00220023--------------------------
PORT 0022-0023 - CHIP SET DATA
Note:    These two ports are used by numerous chipsets.    Various chipsets are
      detailed below.

0022  -W  index for accesses to data port
0023  RW  chip set data
----------P00220023--------------------------
PORT 0022-0023 - Cyrix Cx486SLC/DLC PROCESSOR - CACHE CONFIGURATION REGISTERS
SeeAlso: PORT 0022h"5x86",PORT 0022h"6x86"

0022  -W  index for accesses to next port (see #P0017)
0023  RW  cache configuration register array (indexed by PORT 0022h)
    Note:    the index must be written to PORT 0022h before every access
          to PORT 0023h; out-of-sequence accesses or index values
          not supported by the processor generate external I/O cycles

(Table P0017)
Values for Cyrix Cx486SLC/DLC Cache Configuration register number:
 C0h    CR0 (see #P0019)
 C1h    CR1 (see #P0020)
 C4h    non-cacheable region 1, start address bits 31-24
 C5h    non-cacheable region 1, start address bits 23-16
 C6h    non-cacheable region 1, start addr 15-12, size (low nibble) (see #P0018)
 C7h    non-cacheable region 2, start address bits 31-24
 C8h    non-cacheable region 2, start address bits 23-16
 C9h    non-cacheable region 2, start addr 15-12, size (low nibble) (see #P0018)
 CAh    non-cacheable region 3, start address bits 31-24
 CBh    non-cacheable region 3, start address bits 23-16
 CCh    non-cacheable region 3, start addr 15-12, size (low nibble) (see #P0018)
 CDh    non-cacheable region 4, start address bits 31-24
 CEh    non-cacheable region 4, start address bits 23-16
 CFh    non-cacheable region 4, start addr 15-12, size (low nibble) (see #P0018)
SeeAlso: #P0023,#P0021

(Table P0018)
Values for Cyrix Cx486SLC/DLC non-cacheable region sizes:
 00h    disabled
 01h    4K
 02h    8K
 03h    16K
 04h    32K
 05h    64K
 06h    128K
 07h    256K
 08h    512K
 09h    1M
 0Ah    2M
 0Bh    4M
 0Ch    8M
 0Dh    16M
 0Eh    32M
 0Fh    4G
SeeAlso: #P0017

Bitfields for Cyrix Cx486SLC/DLC Configuration Register 0:
Bit(s)    Description    (Table P0019)
 0    "NC0" first 64K of each 1M noncacheable in real/V86
 1    "NC1" 640K-1M noncacheable
 2    "A20M" enables A20M# input pin
 3    "KEN"  enables KEN# input pin
 4    "FLUSH" enables FLUSH input pin
 5    "BARB" enables internal cache flushing on bus holds
 6    "C0" cache direct-mapped instead of 2-way associative
 7    "SUSPEND" enables SUSP# input and SUSPA# output pins
SeeAlso: #P0017,#P0020,#P0032

Bitfields for Cyrix Cx486SLC/DLC Configuration Register 1:
Bit(s)    Description    (Table P0020)
 0    "RPL" enables output pins RPLSET and RPLVAL#
SeeAlso: #P0017,#P0019,#P0024
----------P00220023--------------------------
PORT 0022-0023 - Cyrix 486S2/D2/DX/DX2/DX4 PROCESSOR - CONFIGURATION REGISTERS
SeeAlso: PORT 0022h"Cx486SLC",PORT 0022h"5x86",PORT 0022h"6x86"

0022  -W  index for accesses to next port (see #P0021)
0023  RW  cache configuration register array (indexed by PORT 0022h)
    Note:    the index must be written to PORT 0022h before every access
          to PORT 0023h; out-of-sequence accesses or index values
          not supported by the processor generate external I/O cycles

(Table P0021)
Values for Cyrix 486S2/D2/DX/DX2/DX4 configuration register number:
 C2h    CR2 (see #P0025)
 C3h    CR3 (see #P0026)
 CDh    SMM region, start address bits 31-24
 CEh    SMM region, start address bits 23-16
 CFh    SMM region, start addr 15-12, size (low nibble) (see #P0018)
 FEh R    Device Identification #0 (see #P0022)
    CPU device ID
 FFh R    Device Identification #1
    bits 3-0: revision
    bits 7-4: stepping
SeeAlso: #P0017,#P0023,#P0031

(Table P0022)
Values for Cyrix device identification:
(#0 /#1)
 00h    Cx486SLC
 01h    Cx486DlC
 02h    Cx486SLC2
 03h    Cx486DLC2
 04h    Cx486SRx
 05h    Cx486DRx
 06h    Cx486SRx2
 07h    Cx486DRx2
 10h    Cx486S (B-step)
 11h    Cx486S2 (B-step)
 12h    Cx486Se (B-step)
 13h    Cx486S2e (B-step)
1Ah/05h    Cx486DX-40
1Bh/08h    Cx486DX2-50
1Bh/0Bh    Cx486DX2-66
1Bh/31h    Cx486DX2-v80
1Fh/36h    Cx486DX4-v100
 28h    5x86 1xs
 29h    5x86 2xs
 2Ah    5x86 1xp
 2Bh    5x86 2xp
 2Ch    5x86 4xs
 2Dh    5x86 3xs
 2Eh    5x86 4xp
 2Fh    5x86 3xp
 30h    6x86 1xs
 31h    6x86 2xs
 32h    6x86 1xp
 33h    6x86 2xp
 34h    6x86 4xs
 35h    6x86 3xs
 36h    6x86 4xp
 37h    6x86 3xp
Note:    #0 is the value in configuration register FEh, while #1 is the value
      in configuration register FFh
SeeAlso: #P0021
----------P00220023--------------------------
PORT 0022-0023 - Cyrix 5x86 PROCESSOR - CONFIGURATION CONTROL REGISTERS
SeeAlso: PORT 0022h"Cx486SLC",PORT 0022h"486S2",PORT 0022h"6x86"

0022  -W  index for accesses to next port (see #P0023)
0023  RW  configuration control register array (indexed by PORT 0022h)
    Note:    the index must be written to PORT 0022h before every access
          to PORT 0023h; out-of-sequence accesses or index values
          not supported by the processor generate external I/O cycles

(Table P0023)
Values for Cyrix 5x86 configuration registers:
 20h    Performance Control (see #P0028)
 C1h    Configuration Control #1 (CCR1) (see #P0024)
 C2h    Configuration Control #2 (CCR2) (see #P0025)
 C3h    Configuration Control #3 (CCR3) (see #P0026)
 CDh    System Memory Management address region #0 (smar0) (see #P0029)
 CEh    System Memory Management address region #1 (smar1)
 CFh    System Memory Management address region #2 (smar2)
 E8h    Configuration Control Register 4
 F0h    Power Management (see #P0030)
 FEh R    Device Identification #0 (see #P0022)
    CPU device ID
 FFh R    Device Identification #1
    bits 3-0: revision
    bits 7-4: stepping
SeeAlso: #P0017,#P0021,#P0031

Bitfields for Cyrix 5x86,6x86 Configuration Control Register 1 (CCR1):
Bit(s)    Description    (Table P0024)
 0    reserved
 1    enable SMM pins
 2    system management memory access
 3    main memory access
 4    (6x86) no LOCK during bus cycles
 6-5    reserved
 7    (6x86) use address region 3 as SMM space
Note:    bits 1,2,7 may only be written when CCR3 bit 0 is enabled
SeeAlso: #P0020,#P0025,#P0026,#P0027

Bitfields for Cyrix 5x86,6x86 Configuration Control Register 2 (CCR2):
Bit(s)    Description    (Table P0025)
 0    reserved
 1    enable write-back cache interface pins
 2    lock NW bit
 3    suspend on HLT instruction
 4    write-through region 1
 5    reserved
 6    enable burst write cycles
 7    enable suspend pins
SeeAlso: #P0024,#P0026,#P0027

Bitfields for Cyrix 5x86,6x86 Configuration Control Register 3 (CCR3):
Bit(s)    Description    (Table P0026)
 0    SMM register lock (can only be cleared in SMM mode or by CPU reset)
 1    NMI enable
 2    linear address burst cycles (5x86,6x86 only)
    =0 Pentium-compatible
    =1 linear sequencing
 3    SMM mode (5x86 only)
    =0 486SL
    =1 Cyrix
 7-4    map enable (5x86,6x86 only)
    0000 only allow access to configuration registers C0h-CFh,FEh,FFh
    0001 enable access to all configuration registers
SeeAlso: #P0024,#P0025,#P0027,#P0028,#P0030

Bitfields for Cyrix 5x86,6x86 Configuration Control Register 4 (CCR4):
Bit(s)    Description    (Table P0027)
 2-0    I/O recovery time (000 = none, else 2^N clocks)
 3    enable memory-read bypassing (5x86 only)
 4    enable directory table entry cache
 6-5    reserved
 7    enable CPUID instruction (stepping 1+ and Cx6x86)
Note:    this register is only accessible when bits 7-4 of CCR3 are 0001
SeeAlso: #P0024,#P0025,#P0026

Bitfields for Cyrix 5x86 Performance Control register:
Bit(s)    Description    (Table P0028)
 0    return stack enabled (speculatively execute code after current CALL)
 1    branch-target buffer enabled
 2    loop enable
 6-3    reserved (0)
 7    load-store serialization enabled
    (memory reads and writes may be reorganized into optimum order)
Note:    this register is only accessible when bits 7-4 of CCR3 are 0001
SeeAlso: #P0030,#P0024

Bitfields for Cyrix 5x86 SMM Address Region register:
Bit(s)    Description    (Table P0029)
 3-0    block size
 23-4    starting address

Bitfields for Cyrix 5x86 Power Management register:
Bit(s)    Description    (Table P0030)
 1-0    core clock to bus clock ratio
    00 1:1
    01 2:1
    10 reserved
    11 3:1
 2    CPU running at half bus speed, ignore bits 1-0
Note:    this register is only accessible when bits 7-4 of CCR3 are 0001
----------P00220023--------------------------
PORT 0022-0023 - Cyrix 6x86 PROCESSOR - CONFIGURATION CONTROL REGISTERS
SeeAlso: PORT 0022h"Cx486",PORT 0022h"5x86"

0022  -W  index for accesses to next port (see #P0023)
0023  RW  configuration control register array (indexed by PORT 0022h)
    Note:    the index must be written to PORT 0022h before every access
          to PORT 0023h; out-of-sequence accesses or index values
          not supported by the processor generate external I/O cycles

(Table P0031)
Values for Cyrix 6x86 configuration registers:
 C0h    Configuration Control Register 0 (CCR0) (see #P0032)
 C1h    Configuration Control #1 (CCR1) (see #P0024)
 C2h    Configuration Control #2 (CCR2) (see #P0025)
 C3h    Configuration Control #3 (CCR3) (see #P0026)
 C4h    Address region 0 (bits 31-24)
 C5h    Address region 0 (bits 23-16)
 C6h    Address region 0 (bits 15-12 and size)
 C7h    Address region 1 (bits 31-24)
 C8h    Address region 1 (bits 23-16)
 C9h    Address region 1 (bits 15-12 and size)
 CAh    Address region 2 (bits 31-24)
 CBh    Address region 2 (bits 23-16)
 CCh    Address region 2 (bits 15-12 and size)
 CDh    Address region 3 (bits 31-24)
 CEh    Address region 3 (bits 23-16)
 CFh    Address region 3 (bits 15-12 and size)
 D0h    Address region 4 (bits 31-24)
 D1h    Address region 4 (bits 23-16)
 D2h    Address region 4 (bits 15-12 and size)
 D3h    Address region 5 (bits 31-24)
 D4h    Address region 5 (bits 23-16)
 D5h    Address region 5 (bits 15-12 and size)
 D6h    Address region 6 (bits 31-24)
 D7h    Address region 6 (bits 23-16)
 D8h    Address region 6 (bits 15-12 and size)
 D9h    Address region 7 (bits 31-24)
 DAh    Address region 7 (bits 23-16)
 DBh    Address region 7 (bits 15-12 and size)
 DCh    Region Control 0
 DDh    Region Control 1
 DEh    Region Control 2
 DFh    Region Control 3
 E0h    Region Control 4
 E1h    Region Control 5
 E2h    Region Control 6
 E3h    Region Control 7
 E8h    Configuration Control Register 4 (see #P0027)
 E9h    Configuration Control Register 5 (see #P0033)
 FEh R    Device Identification #0 (see #P0022)
    CPU device ID
 FFh R    Device Identification #1
    bits 3-0: revision
    bits 7-4: stepping
SeeAlso: #P0017,#P0023

Bitfields for Cyrix 6x86 Configuration Control Register 0:
Bit(s)    Description    (Table P0032)
 7-2    ???
 1    address region 640K-1M is noncacheable
 0    ???
SeeAlso: #P0019

Bitfields for Cyrix 6x86 Configuration Control Register 5:
Bit(s)    Description    (Table P0033)
 7-6    reserved
 5    enable all address-region registers (control registers C4h-DBh)
 4    assert LBA# pin on all accesses to 640K-1M
 3-1    reserved
 0    allocate new cache lines only on read misses
SeeAlso: #P0032,#P0027,#P0031
----------P00220023--------------------------
PORT 0022-0023 - GoldStar 286 - CHIP SET CONFIGURATION REGISTERS
SeeAlso: PORT 0022h"Cx486SLC",PORT 0022h"486S2",PORT 0022h"6x86"

0022  -W  index for accesses to next port (see #P0034)
0023  RW  configuration control register array (indexed by PORT 0022h)

(Table P0034)
Values for GoldStar 286 chipset configuration register index:
 60h    turbo control
    write 00h to PORT 0023h to turn on turbo, 10h to turn it off
--------X-P00220023--------------------------
PORT 0022-0023 - Intel 82358DT 'Mongoose' EISA CHIPSET - 82359 DRAM CONTROLLER
Notes:    this chip uses a chip ID of 01
    the LIM register herein use a chip ID of 1A
Index: Intel 82351

0022  -W  index for accesses to data port (see #P0036,#P0037,#P0038)
0023  RW  chip set data

(Table P0035)
Values for Intel 82351/82359 chip ID:
 01h    82359 DRAM controller, general registers
 02h    82351 EISA local I/O support
 A1h    82359 DRAM controller, EMS registers
 FFh    no chip accessible (default)
SeeAlso: #P0036,#P0037,#P0038

(Table P0036)
Values for 82359 DRAM controller general register index:
 00h    DRAM bank 0 type
    bit 7    unknown
    bit 6-4    000 DRAM in bank 0 (standard)
        001 bank 1
        010 bank 2
        011 bank 3
        100 banks 0,1
        101 banks 2,3
        110 banks 0,1,2,3
        111 empty (standard for 1,2,3)
    bit 3-2    unknown
    bit 1-0    00 64K chips used
        01 256K
        10 1M
        11 4M
 01h    DRAM bank 1 type
 02h    DRAM bank 2 type
 03h    DRAM bank 3 type
 04h    DRAM speed detection/selection
 05h    DRAM interleave control
 06h    RAS line mode
 07h    cache-enable selection
 08h    mode register A (DRAM, cache)
 09h    mode register B (cache, burst modes, BIOS size)
 0Ah    mode register C (concurrency control, burst/cycle speed)
 10h    host timing
 11h    host-system delay timing
 12h    system timing
 13h    DRAM row precharge time
 14h    DRAM row timing
 15h    DRAM column timing
 16h    CAS pulse width
 17h    CAS-to-MDS delay
 21h    chip ID register -- selects which chip responds on these ports
    (see #P0035)
 28h-2Ch    parity-error trap address
 30h    page hit cycle length (read)
 31h    page miss cycle length (read)
 32h    row miss cycle length (read)
 33h    page hit cycle length (write)
 34h    page miss cycle length (write)
 35h    row miss cycle length (write)
 40h    memory enable 00000h-7FFFFh
 41h    memory enable 80000h-9FFFFh
 42h    memory enable A0000h-AFFFFh
 43h    memory enable B0000h-BFFFFh
 44h    memory enable C0000h-CFFFFh
 45h    memory enable D0000h-DFFFFh
 46h    memory enable E0000h-EFFFFh
 47h    memory enable F0000h-FFFFFh
 4Eh    remap 80000h-FFFFFh to extended memory
 50h-53h    programmable attribute map 1
 54h-57h    programmable attribute map 2
 58h-5Bh    programmable attribute map 3
 5Ch-5Fh    programmable attribute map 4
 83h-84h    split address register (address bits A31-A20)
 85h    cache control
 8Bh    system throttle
 8Ch    host throttle
 8Dh    host memory throttle watchdog
 8Eh    host system throttle
 8Fh    host system throttle watchdog
 90h    RAM enable
 91h    RAM disable
 92h-93h    elapsed-time registers
 94h-95h    host memory ownership request
 96h-97h    system memory ownership request
 98h-99h    host memory ownership
 9Ah-9Bh    system bus ownership
 9Ch-9Dh    host system bus request
 9Eh-9Fh    memory ownership transfer
SeeAlso: #P0037,#P0038

(Table P0037)
Values for Intel 82359 DRAM controller EMS register index:
 00h    EMS cotnrol
 21h    chip ID register -- selects which chip responds on these ports
    (see #P0035)
 80h-8Fh    EMS page registers, pages 0-7
SeeAlso: #P0036,#P0038

(Table P0038)
Values for Intel 82351 EISA Local I/O register index:
 21h    chip ID register -- selects which chip responds on these ports
    (see #P0035)
 C0h    peripheral enable register A
 C1h    peripheral enable register B
 C2h    parallel configuration register
 C3h    serial configuration register A
 C4h    floppy disk controller configuration register
 C5h    serial configuration register B
 C6h    COM3 port address (low)
 C7h    COM3 port address (high)
 C8h    COM4 port address (low)
 C9h    COM4 port address (high)
 D0h-D3h    general chip select lines 0-3 (mask registers)
 D4h-D7h    general chip select line addresses 0-3 (low bytes)
 D8h-DBh    general chip select line addresses 0-3 (high bytes)
 DCh    extended CMOS RAM page port address (low)
 DDh    extended CMOS RAM page port address (high)
 DFh    extended CMOS RAM access select address (high byte)
 E8h-EBh    EISA ID configuration registers (reflect at PORT 0C80h)
SeeAlso: #P0036,#P0037
--------X-P00220023--------------------------
PORT 0022-0023 - Intel 82374EB/SB EISA CHIPSET
Index: Intel 82374EB;Intel 82374SB

0022  -W  index for accesses to data port (see #P0039)
0023  RW  chip set data

!!!29047604.pdf pg. 36
(Table P0039)
Values for Intel 82374 register index:
 02h    ESC identification register
    (82374 will only respond to ports 0022h and 0023h after an 0Fh
     is written to this register)
 08h    revision ID register
 40h    mode select (see #P0040)
 42h    BIOS Chip Select A (see #P0041)
 43h    BIOS Chip Select B (see #P0042)
 4Dh    EISA clock divisor (see #P0043)
 4Eh    peripheral Chip Select A (see #P0044)
 4Fh    peripheral Chip Select B (see #P0045)
 50h-53h EISA ID registers
 57h    scatter/gather relocate base address (see also #01075)
    (specifies bits 15-0 if S/G port addresses [low byte always 10h-3Fh])
 59h    APIC base address relocation
 60h-63h PCI IRQn# route control (see also #01076)
 64h    general-purpose chip select low address 0
 65h    general-purpose chip select high address 0
 66h    general-purpose chip select mask register 0
 68h    general-purpose chip select low address 1
 69h    general-purpose chip select high address 1
 6Ah    general-purpose chip select mask register 1
 6Ch    general-purpose chip select low address 2
 6Dh    general-purpose chip select high address 2
 6Eh    general-purpose chip select mask register 2
 6Fh    general-purpose peripheral X-Bus control
---SB only---
 70h    PCI/APIC control (see #P0046)
 88h    test control
 A0h    SMI control (see #P0047)
 A2h-A3h  SMI enable (see #P0048)
 A4h-A7h  System Event Enable (see #P0049)
 A8h    Fast-Off timer
 AAh-ABh SMI Request (see #P0050)
 ACh    Clock Scale STPCLK# low timer
 AEh    Clock Scale STPCLK# high timer

Bitfields for 82374EB mode select (register 40h):
Bit(s)    Description    (Table P0040)
  7    reserved
  6    enable the selected (MREQ[7:4]#/PIRQ[3:0]# functionality
  5    enable/disable configuration RAM Page Address (CPG[4:0]) generation
    =1 accesses to the configuration RAM space will generate the RAM page
      address on the LA[31:27]# pins (default)
    =0 the CPG[4:0] signals will not be activated
  4    General Purpose Chip Selects: select GPCS[2:0]#/ECS[2:0] pins' function
    =0 GPCS[2:0]# functionality is selected
    =1 ESC[2:0] functionality is selected
  3    System Error: enable generation of NMI based on SERR# signal pulsing
    =0 NMI is negated and SERR# is disabled from generating an NMI
    =1 NMI signal is asserted when NMIs are enabled via the NMIERTC
      Register and SERR# is asserted
    Note: other NMI sources are enabled/disabled via the NMISC register
  2-0    PIRQx Mux/Mapping Control: select muxing/mapping of PIRQ[3:0]# with
      MREQ[7:4] and group of X-Bus signals (DLIGHT#, RTCWR#, RTCRD#).
    Different bit combinations select the number of EISA slots or group of
      X-Bus signals which can be supported with the certain number of
      PIRQx# signals by determining the functionality of pins
      AEN[4:1]/EAEN[4:1], MACK[3:0]#/EMACK[3:0]#, MREQ[7:4]/PIRQ[3:0]#,
      DLIGHT#/PIRQ0#, FDCCS#/PIRQ1#, RTCWR#/PIRQ2#, and RTCRD#/PIRQ3#.
SeeAlso: #P0039

Bitfields for 82374EB BIOS Chip Select A "BIOSCSA" (register 42h):
Bit(s)    Description    (Table P0041)
  7-6    reserved
  5    Enlarged BIOS: assert LBIOSCS# for memory read cycles to locations
      FFF80000h-FFFDFFFFh
  4    High BIOS: assert LBIOSCS# for memory read cycles to locations
      0F0000h-0FFFFFh, FF0000h-FFFFFFh, and FFFF0000h-FFFFFFFFh
  3    Low BIOS 4: assert LBIOSCS# for memory read cycles to locations
      0EC000h-0EFFFFh, FFEEC000h-FFEEFFFFh, and FFFEC000h-FFFEFFFFh
  2    Low BIOS 3: assert LBIOSCS# for memory read cycles to locations
      0E8000h-0EBFFFh, FFEE8000h-FFEEBFFFh, and FFFE8000h-FFFEBFFFh
  1    Low BIOS 2: assert LBIOSCS# for memory read cycles to locations
      0E4000h-0E7FFFh, FFEE4000h-FFEE7FFFh, and FFFE4000h-FFFE7FFFh
  0    Low BIOS 1: assert LBIOSCS# for memory read cycles to locations
      0E0000h-0E3FFFh, FFEE0000h-FFEE3FFFh, and FFFE0000h-FFFE3FFFh
Note:    if bit 3 of register 43h (BIOSCSB) is set, then LBIOSCS# will be
      asserted for write cycles as well as read cycles on any enabled range
SeeAlso: #P0039,#P0042

Bitfields for 82374EB BIOS Chip Select B (register 43h):
Bit(s)    Description    (Table P0042)
  7-4    Reserved
  3    BIOS Write Enable: assert LBIOSCS# for both memory read AND write
      cycles for addresses in the decoded and enabled BIOS range
      (see #P0041)
  2    16 Meg BIOS: assert LBIOSCS# for memory read cycles to locations
      FF0000h-FFFFFFh
  1    High VGA BIOS: assert LBIOSCS# for memory read cycles to locations
      0C4000h-0C7FFFh
  0    Low VGA BIOS: assert LBIOSCS# for memory read cycles to locations
      0C0000h-0C3FFFh
Note:    if bit 3 of register 43h (BIOSCSB) is set, then LBIOSCS# will be
      asserted for write cycles as well as read cycles on any enabled range
      above
SeeAlso: #P0039,#P0041

Bitfields for 82374EB EISA clock divisor (register 4Dh):
Bit(s)    Description    (Table P0043)
  7-6    Reserved
  5    Co-processor Error: specify if the FERR# signal is connected to the
      ESC internal IRQ13 interrupt signal.
    =0 FERR# signal is ignored by the ESC (i.e. this signal is not
      connected to any logic in the ESC).
    =1 assert IRQ13 to the interrupt controller if FERR# signal is asserted
  4    82374EB: Reserved
    82374SB: ABFULL (with IRQ12):
    =0 internal IRQ12 is directed to the interrupt controller and
      transitions on ABFULL have no effect on this interrupt signal
    =1 the assertion of ABFULL is latched and directed to the internal
      IRQ12 signal in the following manner:
        If the interrupt controller is programmed for edge detect mode on
          IRQ12, a low-to-high transition is generated on the internal
          IRQ12 signal. Transitions on the IRQ12 input pin are not
          reflected on the internal IRQ12 signal.
        If the interrupt controller is programmed for level-sensitive mode,
          a high-to-low transition is generated on the internal IRQ12
          signal.  Transitions on the IRQ12 input pin are also reflected
          on the internal IRQ12 signal.
    The latching of the ABFULL signal is cleared by an I/O read of
      address 60h (no aliasing) or by a hard reset.
  3    82374EB: Reserved
    82374SB: Keyboard Full (KBFULL): select edge-detect KBFULL function on
      the IRQ1 input signal
    =0 IRQ1 is directed to the interrupt controller
    =1 (default) IRQ1 is latched and directed to the interrupt controller.
      The latched IRQ1 is cleared by an I/O read of address 60h (no
      aliasing) or by a hard reset.
  2-0    Clock Divisor: select the integer used to divide the PCICLK down to
      generate the BCLK.
    000 4 (33.33 MHz) 8.33 MHz (default after reset)
    001 3 (25 MHz) 8.33 MHz
    01x reserved
    1xx reserved
SeeAlso: #P0039

Bitfields for 82374EB peripheral Chip Select A (register 4Eh):
Bit(s)    Description    (Table P0044)
  7    Reserved
  6    Keyboard Controller Mapping
    =0 the keyboard controller encoded chip select signal and the X-Bus
      transceiver enable (XBUSOE#) are generated for accesses to address
      locations 60h (82374EB/SB), 62h (82374EB only), 64h (82374EB/SB) and
      66h (82374EB only).
    =1 the keyboard controller chip select signals are generated for
      accesses to the above address locations. However XBUSOE# is disabled.
    Note:    bit 1 must be 1 for either value of this configuration bit to
          decode an access to locations 60h, 62h, 64h, or 66h.
  5    Floppy Disk/IDE Controller Address range
    =0 primary (1Fxh and 3Fxh)
    =1 secondary (17xh and 37xh)
  4    IDE DECODE: enable or disable IDE locations 1F0h-1F7h (primary) or
      170h-177h (secondary) and 3F6h,3F7h (primary) or 376h,377h (sec).
    82374EB: When this bit is set to 0, the IDE encoded chip select signals
      and the X-Bus transceiver signal (XBUSOE#) are not generated for
      these addresses.
    82374SB: When this bit is set to 0, the IDE encoded chip select signals
      and the X-Bus transceiver signal (XBUSOE#) are not generated for
      addresses 1F0h-1F7h (primary) or 170h-177h (secondary) and 3F6h or
      376h.     Read/write accesses to addresses 377h and 3F7h are not
      disabled and still generate XBUSOE#.
  3-2    Floppy Disk and IDE/Floppy Disk Decodes: Bits 2 and 3 are used to
      enable or disable the floppy locations as indicated. Bit 2 defaults
      to enabled (1) and bit 3 defaults to disabled (0) when a reset occurs
  1    Keyboard Controller Decode: enable the keyboard controller address
      locations 60h (82374EB/SB), 62h (82374EB only), 64h (82374EB/SB), and
      66h (82374EB only).
    =0 the keyboard controller encoded chip select signals and the X-Bus
      transceiver signal (XBUSOE#) are not generated for these locations
    Note:    the value of this bit affects control function (keyboard
          controlling mapping) provided by bit 6 of this register.
  0    Real Time Clock Decode: enable the RTC address locations 70h-77h.
    =0 the RTC encoded chip    select signals RTCALE, RTCRD, RTCWR#, and
      XBUSOE# signals are not generated for these addresses.
SeeAlso: #P0039,#P0045

Bitfields for 82374EB peripheral Chip Select B (register 4Fh):
Bit(s)    Description    (Table P0045)
  7    CRAM Decode: enable I/O write accesses to location 0C00h and I/O
      read/write accesses to locations 0800h-08FFh. The configuration RAM
      read and write (CRAMRD#, CRAMWR#) strobes are valid for accesses to
      0800h-08FFh.
  6    Port 92 Decode: enable access to Port 92 (default at PCIRST is enabled)
  5-4    select which Parallel Port address range (LPT1, 2, or 3) is decoded.
    00 LPT1 (3BCh-3BFh)
    01 LPT2 (378h-37Fh)
    10 LPT3 (278h-27Fh)
    11 disabled
  3-2    Serial Port B Address Decode: If either COM1 or COM2 address ranges
      are selected, these bits default to disabled upon PCIRST.
    00 3F8h-3FFh (COM1)
    01 2F8h-2FFh (COM2)
    10 Reserved
    11 Port B disabled
  1-0    Serial Port A Address Decode: If either COM1 or COM2 address ranges are
      selected, these bits default to disabled upon PCIRST.
    00 3F8h-3FFh (COM1)
    01 2F8h-2FFh (COM2)
    10 Reserved
    11 Port A disabled
SeeAlso: #P0039,#P0044

Bitfields for 82374SB PCI/APIC control (register 70h):
Bit(s)    Description    (Table P0046)
  7-2    Reserved
  1    SMI Routing Control (SMIRC)
    =1 SMI is routed via the APIC
    =0 SMI is routed via the SMI# signal
    Note:    when SMRCe1, INTR can not be routed through the APIC, since it
          is sharing the APIC interrupt input with SMI#.
  0    INTR Routing Control (INTRC): When APIC is enabled (in mixed or pure
      APIC mode), this bit allows the ESC's external INTR signal to be
      masked (forces INTR to the inactive state but does not tri-states
      the signal). Thus, the CPU's INTR pin can be used (by providing a
      simple -gate) for the APIC Local Interrupt (LINTRx). However, INTR
      must not be masked via this bit when APIC is disabled and INTR is
      the only mechanism to signal the 8259 recognized interrupts to the
      CPU.
    =1 INTR is disabled (APIC must be enabled)
    =0 INTR is enabled
SeeAlso: #P0039

Bitfields for 82374SB SMI control (register A0h):
Bit(s)    Description    (Table P0047)
  7    reserved (0)
  6-4    reserved
  3    Fast Off Timer Freeze (CTMRFRZ): disable the Fast Off Timer
    Disabling the timer prevents time-outs from occurring while executing
      SMM code.
  2    STPCLK# Scaling Enable (CSTPCLKSC)
    =0 (default) scaling control of the STPCLK# signal is disabled.
    =1, the STPCLK# signal scaling control is enabled. When enabled (and
      bit 1=1, enabling the STPCLK# signal), the high and low times for the
      STPCLK# signal are controlled by the Clock Scaling STPCLK# High Timer
      and Clock Scaling STPCLK# Low Timer Registers, respectively.
  1    STPCLK# Signal Enable (CSTPCLKE): permits software to place the CPU
      into a low power state.
    =0 (default) STPCLK# signal is disabled and is negated (high)
    =1 the STPCLK# signal is enabled and a read from the APMC Register
      causes STPCLK# to be asserted
    Software can set this bit to 0 by writing a 0 to it or by any write to
      the APMC Register.
  0    SMI# Gate (CSMIGATE)
    =0 (default) the SMI# signal is masked and negated
    =1 SMI# signal is enabled and a system management interrupt condition
      causes the SMI# signal to be asserted
Note:    bit 0 only affects the SMI# signal and does not affect the
      detection/recording of SMI events (i.e., it does not affect the SMI
      status bits in the SMIREQ Register). Thus, SMI conditions can be
      pending when bit 0 is set to 1; if an SMI is already pending, the
      SMI# signal is asserted.
SeeAlso: #P0039

Bitfields for 82374SB SMI enable (register A2h-A3h):
Bit(s)    Description    (Table P0048)
  15-8    Reserved
  7    APMC Write SMI Enable
    =0 writes to the APMC Register do not generate an SMI
    =1 writes to the APMC Register generate an SMI
  6    EXTSMI# SMI Enable
    =1 asserting the EXTSMI# input signal generates an SMI
  5    Fast Off Timer SMI Enable
    =1 Fast-Off timer generates an SMI when it decrements to zero
  4    IRQ12 SMI Enable (PS/2 Mouse Interrupt)
    =1 asserting the IRQ12 input signal generates an SMI
  3    IRQ8 SMI Enable (RTC Alarm Interrupt)
    =1 asserting the IRQ8 input signal generates an SMI
  2    IRQ4 SMI Enable (COM2/COM4 Interrupt or Mouse)
    =1 asserting the IRQ3 input signal generates an SMI
  1    IRQ3 SMI Enable (COM1/COM3 Interrupt or Mouse)
    =1 asserting the IRQ3 input signal generates an SMI
  0    IRQ1 SMI Enable (Keyboard Interrupt)
    =1 asserting the IRQ1 input signal generates an SMI
SeeAlso: #P0039

Bitfields for 82374SB System Event Enable (register A4h-A7h):
Bit(s)    Description    (Table P0049)
  31    Fast Off SMI Enable (FSMIEN)
    =1 an SMI causes a system event that re-loads the Fast Off Timer and a
      break event that negates the STPCLK# signal
    =0 an SMI does not re-load the Fast Off Timer or negate the STPCLK#
      signal
  30    reserved
  29    Fast Off NMI Enable (FNMIEN)
    =1 an NMI (e.g., parity error) causes a system event that re-loads the
      Fast Off Timer and a break event that negates the STPCLK# signal
    =0 an SMI does not re-load the Fast Off Timer or negate    the STPCLK#
      signal.
  28-16 reserved
  15-3    These bits are used to prevent the system from entering Fast Off and
      break any current powerdown state when the selected hardware
      interrupt (IRQ15-IRQ3) occurs
    =1 the corresponding interrupt causes a    system event that re-loads the
      Fast Off Timer and a break event that    negates the STPCLK# signal
    =0 the corresponding interrupt does not re-load the Fast Off Timer or
      negate the STPCLK# signal
  2    reserved
  1-0    These bits are used to prevent the system from entering Fast Off and
      break any current powerdown state when the selected hardware
      interrupt (IRQ1-IRQ0) occurs
    =1 the corresponding interrupt causes a    system event that re-loads the
      Fast Off Timer and a break event that    negates the STPCLK# signal
    =0 the corresponding interrupt does not re-load the Fast Off Timer or
      negate the STPCLK# signal
SeeAlso: #P0039

Bitfields for 82374SB SMI Request (register AAh-ABh):
Bit(s)    Description    (Table P0050)
  15-8    Reserved
  7    APM SMI Status (RAPMC): set to 1 to indicate that a write to the APM
      Control Register caused an SMI
  6    EXTSMI# SMI Status (REXT): set to 1 when EXTSMI# caused an SMI
  5    Fast Off Timer Expired Status (RFOT): set to 1 to indicate that the
      Fast Off Timer expired and caused an SMI.  The Fast Off  timer
      re-starts counting on the next clock after it expires.
  4    SMI caused by IRQ12
  3    SMI caused by IRQ8
  2    SMI caused by IRQ4
  1    SMI caused by IRQ3
  0    SMI caused by IRQ1
SeeAlso: #P0039
----------P00220023--------------------------
PORT 0022-0023 - CHIPSET FROM ETEC CHEETAH ET6000 (SINGLE CHIP)

0022  RW  chip set data
0023  ?W  index for accesses to data port (see #P0051)

(Table P0051)
Values for Etec Cheetah ET6000 chip set register index:
 10h    system configuration register (see #P0052)
 11h    cache configuration & non-cacheable block size register (see #P0053)
 12h    non-cacheable block address register
    bit 7-1    non-cacheable address, A25-A19
    bit 0    reserved
 13h    DRAM bank & type configuration register (see #P0054)
 14h    DRAM configuration register (see #P0055)
 15h    shadow RAM configuration register (see #P0056)

Bitfields for Etec Cheetah ET6000 system configuration register:
Bit(s)    Description    (Table P0052)
 7-6    00 turbo/non-turbo
    01 local device supported
    10 suspend mode
    11 illegal
 5    reserved
 4    refresh selection
    0 = AT type refresh
    1 = concurrent refresh
 3    slow refresh  95mSec enabled
 2    fast reset delay
    0 = do not use delay
    1 = wait for 2mSec delay
 1    wait for HALT after KBDRST
 0    RAM at A0000-BFFFF
    0 = AT bus cycle
    1 = local bus cycle
SeeAlso: #P0051

Bitfields for Etec Cheetah ET6000 cache configuration register:
Bit(s)    Description    (Table P0053)
 7-5    000 disabled
    001 512K
    010 1M
    011 2M
    100 4M
    101 8M
    110 16M
    111 32M
 4    DRAM banks
    0 = 2-bank DRAM
    1 = 4-bank DRAM
 3-0    reserved
SeeAlso: #P0051

Bitfields for Etec Cheetah ET6000 DRAM bank & type configuration register:
Bit(s)    Description    (Table P0054)
 7-6    bank 3 DRAM type
    00 none
    01 256K
    10 1M
    11 4M
 5-4    bank 2 DRAM type
 3-2    bank 1 DRAM type
 1-0    bank 0 DRAM type
SeeAlso: #P0051

Bitfields for Etec Cheetah ET6000 DRAM configuration register:
Bit(s)    Description    (Table P0055)
 7    on-board memory range 15M to 16M disabled
 6    on-board memory range 512K-640K disabled
 5    ROM chip select at C0000-DFFFF enabled
 4    RAS to CAS time
    0 = 1 SYSCLCK,    not for R0WS
    1 = 2 SYSCLCK
 3    RAS precharge time
    0 = 1.5 SYSCLCK
    1 = 2.5 SYSCLCK
 2-1    read cycle wait state
    00 = 0 wait state
    01 = 1 ws
    10 = 2 ws
    11 = 3 ws
 0    write cycle wait state
    0 = 0 ws
    1 = 1 ws
SeeAlso: #P0051

Bitfields for Etec Cheetah ET6000 shadow RAM configuration register:
Bit(s)    Description    (Table P0056)
 7    shadow at C0000-FFFFF
    0 = non-cacheable
    1 = cacheable and cache-write-proteced
 6    access ROM/RAM at F0000-FFFFF
    0 = read from ROM, write to RAM
    1 = read from shadow, write is protected
 5    access ROM/RAM at E0000-EFFFF
    0 = access on-board ROM, AT bus cycle
    1 = access shadow E0000-EFFFF enabled
 4    RAM at E0000-EFFFF is read-only
 3    access ROM/RAM at D0000-DFFFF
    0 = access on-board ROM, AT bus cycle
    1 = access shadow D0000-DFFFF enabled
 2    RAM at D0000-DFFFF is read-only
 1    access ROM/RAM at C0000-CFFFF
    0 = access on-board ROM, AT bus cycle
    1 = access shadow C0000-CFFFF enabled
 0    RAM at C0000-CFFFF is read-only
SeeAlso: #P0051
----------P00220023--------------------------
PORT 0022-0023 - Hewlett-Packard Hornet chipset (HP 100LX/200LX)

0022  RW  index for accesses to data port (see Table P189)
0023  RW  chip set data

(Table P0057)
Values for HP Hornet chipset register index:
 1Eh    buzzer volume/clock oscillator speed
    bit 7-6: buzzer volume
    bit 5-4: system oscillator speed
        00: 10.738636MHz
        01: 15.836773MHz(HP 100/200LX has oscillator with this speed)
        10: 21.477272MHz
        11: 31.673550MHz
 21h    display timing???
 23h    LCD contrast (see INT15h AH=62h)
    valid values: 00h-1fh (1fh is the darkest)
 51h    power adapter status
    bit 7-1: ???
    bit 0: power adapter status(0=inactive/1=active)
 52h    nicad charge status
    bit 7-3: ???
    bit 2: battery charging status(0=???/1=slow charge)
    bit 1-0: ???
 53h    nicad charge status
    bit 7-1: ???
    bit 0: battery charging status(0=???/1=fast charge)
 80h    memory wait for internal ROM
    valid values: 00h-07h
 81h    memory wait for internal RAM
    valid values: 00h-03h
 82h    memory wait for external RAM
    valid values: 00h-0fh
 87h    battery status???
----------P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C100/110 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)

0022  -W  configuration register index (see #P0058)
0023  RW  configuration register data

(Table P0058)
Values for Chips&Technologies 82C100/110 configuration register index:
 40h    clock mode/size (see #P0059)
 41h    system configuration (see #P0060)
 42h    configuration valid (see #P0061)
 43h    DIP switch emulation (see #P0062)
 44h-47h substitute NMI vector, bytes 0-3
    (these specify the vector to be substituted at the INT 02 vector's
      memory address whenever an NMI occurs, preventing application
      software from modifying the NMI handler)
 48h    refresh timer counter (see #P0063)
 49h    wait state select, refresh enable, keyboard type (see #P0064)
 4Ah    reserved
 4Bh    sleep/memory configuration (see #P0065)
 4Ch    EMS configuration (see #P0066)
 4Dh-4Fh reserved

Bitfields for Chips&Technologies 82C100 clock mode/size register:
Bit(s)    Description    (Table P0059)
 !!!
!!!chips\82c110.pdf p.35
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 system configuration register:
Bit(s)    Description    (Table P0060)
 !!!
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 configuration valid register:
Bit(s)    Description    (Table P0061)
 !!!
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C110 DIP Switch Emulation register:
Bit(s)    Description    (Table P0062)
 !!!chips\82c110.pdf p.36
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 refresh timer count register:
Bit(s)    Description    (Table P0063)
 !!!
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 wait state select register:
Bit(s)    Description    (Table P0064)
 !!!
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 sleep/memory configuration:
Bit(s)    Description    (Table P0065)
 !!!
SeeAlso: #P0058

Bitfields for Chips&Technologies 82C100 EMS configuration register:
Bit(s)    Description    (Table P0066)
 !!!
SeeAlso: #P0058
----------P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C235 "SCAT" - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)

0022  -W  configuration register index (see #P0067)
0023  RW  configuration register data

(Table P0067)
Values for Chips&Technologies 82C235 configuration register index:
 01h    DMA wait-state control
 40h    version (read-only)
 41h    clock control
 42h-43h reserved (but listed as read-write in docs)
 44h    peripheral control
 45h    miscellaneous status
 46h    power management
 47h    reserved
 48h    ROM enable
 49h    RAM write-protect control
 4Ah    shadow RAM enable 1
 4Bh    shadow RAM enable 2
 4Ch    shadow RAM enable 3
 4Dh    DRAM configuration
 4Eh    extended boundary
 4Fh    EMS control
 !!!chips\82c235.pdf p.87, p.140
----------P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C311 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)

0022  -W  configuration register index (see #P0068)
0023  RW  configuration register data

(Table P0068)
Values for Chips&Technologies 82C311 configuration register index:
 04h    version (read-only)   !!!chips\82c311.pdf p.65
 05h    AT-bus command delay
 06h    AT-bus wait-state control
 08h    identification
 09h    low RAM/ROM configuration
 0Ch    memory enable map (80000h-9FFFFh)
 0Dh    memory enable map (A0000h-BFFFFh)
 0Eh    memory enable map (C0000h-DFFFFh)
 0Fh    memory enable map (E0000h-FFFFFh)
 10h    block 0 type and start address
 11h    block 0 DRAM timing
 12h    block 1 type and start address
 13h    block 1 DRAM timing
 14h    block 2 type and start address
 15h    block 2 DRAM timing
 16h    block 3 type and start address
 17h    block 3 DRAM timing
 18h    memory block types
 20h    cache control
 21h    directory RAM control 1
 22h    tag RAM directory address (low)
 23h    reference location
 24h    SRAM configuration/direct access address
 25h    directory RAM control 2
 26h    READY timeout
 28h    error source/address
 29h    error address (bits 23-16)
 2Ah    memory enable map (00000h-7FFFFh)
 2Bh    miscellaneous control
 2Ch    middle RAM/ROM configuration
 2Fh    page mode posted-write control (82C311 rev. C only)
 30h    block 0 non-cacheable address (bits 23-16)
 31h    block 0 non-cacheable address (bits 15-12) and size
 32h    block 1 non-cacheable address (bits 23-16)
 33h    block 1 non-cacheable address (bits 15-12) and size
 34h    block 2 non-cacheable address (bits 23-16)
 35h    block 2 non-cacheable address (bits 15-12) and size
 36h    block 3 non-cacheable address (bits 23-16)
 37h    block 3 non-cacheable address (bits 15-12) and size
 38h    block 0/1 non-cacheable addresses (bits 26-24)
 39h    block 2/3 non-cacheable addresses (bits 26-24)
 60h    fast reset control
!!!chips\82c311.pdf p.76, p.115
----------P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C315 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)
SeeAlso: PORT 0022h"82C311",PORT 0022h"82C316"

0022  -W  configuration register index (see #P0069)
0023  RW  configuration register data

(Table P0069)
Values for Chips&Technologies 82C315 configuration register index:
 07h    processor and bus clock source selection (see #P0070)

Bitfields for C&T 82C315 clock source selection register:
Bit(s)    Description    (Table P0070)
 7-5    reserved (0)
 4    80387 is present
 3    processor clock select
    =0 CLK2IN
    =1 AT bus state machine clock
 2-0    bus clock source select
    000 CLK2IN/5
    001 CLK2IN/4
    010 CLK2IN/3
    011 CLK2IN/2
    100 ATCLK
SeeAlso: #P0069
----------P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C316 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)
SeeAlso: PORT 0022h"82C311",PORT 0022h"82C315",PORT 0022h"82C811"

0022  -W  configuration register index (see #P0071)
0023  RW  configuration register data

(Table P0071)
Values for Chips&Technologies 82C316 configuration register index:
 01h    clock/wait-state control    !!!chips\cs8233.pdf p.178
 26h    RTC/NMI/Coprocessor reset    !!!chips\cs8233.pdf p.231
 71h    programmable I/O port 1 address, bits 15-8
 72h    programmable I/O port 1 address, bits 7-0
 73h    programmable I/O port 1 enable
 74h    programmable I/O port 2 address, bits 15-8
 75h    programmable I/O port 2 address, bits 7-0
 76h    programmable I/O port 2 enable
 77h    programmable I/O port 3 address, bits 15-8
 78h    programmable I/O port 3 address, bits 7-0
 79h    programmable I/O port 3 enable
SeeAlso: #P0069
--------h-P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 82C811/82C812 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)
SeeAlso: PORT 0022h"82C311",PORT 0022h"82C315"

0022  -W  configuration register index (see #P0072)
0023  RW  configuration register data

(Table P0072)
Values for Chips&Technologies 82C811/812 configuration register index:
 60h    (82C811) processor clock select (see #P0073)
 61h    (82C811) command delay (see #P0074)
 62h    (82C811) wait states (see #P0075)
---82C812---
 64h    version (see #P0076)
 65h    ROM configuration
 66h    memory enable 1
 67h    memory enable 2
 68h    memory enable 3
 69h    memory enable 4
 6Ah    bank 0/1 enable
 6Bh    memory configuration
 6Ch    bank 2/3 enable
 6Dh    EMS base address
 6Eh    EMS address extension
 6Fh    miscellaneous
!!!chips\cs8281.pdf p.48

Bitfields for C&T 82C811 processor clock select:
Bit(s)    Description    (Table P0073)
 7-6    82C811 release number (00 = initial release)
 5    fast CPU reset initiated by changing this bit from 0 to 1
 4    processor clock
    0 CLK2IN (default)
    1 BCLK
 3    reserved
 2    enable NMI generate on timeout of local-bus READY# signal
 1    reserved
 0    local-bus READY# signal timed out (128 clock cycles0
SeeAlso: #P0072,#P0074,#P0075

Bitfields for C&T 82C811 command delay register:
Bit(s)    Description    (Table P0074)
 7    enable additional address bus hold time
 6    reserved (1)
 5-4    AT-bus 16-bit memory access delay, in BCLK cycles (default = 0)
 3-2    AT-bus 8-bit memory access delay, in BCLK cycles (default = 1)
 1-0    I/O command delay, in BCLK cycles (default = 1)
SeeAlso: #P0072,#P0073,#P0075

Bitfields for C&T 82C811 wait states register:
Bit(s)    Description    (Table P0075)
 7    80387sx is present
 6    coprocessor is ready
 5-4    AT-bus 16-bit cycle wait states (default = 3)
 3-2    AT-bus 8-bit cycle wait states (00=two ... 11=five [default])
 1-0    bus clock (BCLK)
    00 CLK2IN/2 (default)
    01 CLK2IN/3
    10 ATCLK
    11 reserved
SeeAlso: #P0072,#P0073,#P0074

Bitfields for C&T 82C812 version register:
Bit(s)    Description    (Table P0076)
 7    NEATsx memory controller (0 = 82C812)
 6-5    82C812 revision (00 = initial release)
 4-0    reserved
SeeAlso: #P0072
--------h-P00220023--------------------------
PORT 0022-0023 - Chips&Technologies 84031/84035 - CONFIGURATION REGISTERS
Note:    each access to PORT 0023h must immediately follow a write to
      PORT 0022h (this is to avoid accidental accesses)
SeeAlso: PORT 0022h"82C311",PORT 0022h"82C315"

0022  -W  configuration register index (see #P0077)
0023  RW  configuration register data

(Table P0077)
Values for Chips&Technologies 84031/84035 configuration register index:
 01h    (84035) IPC DMA controller wait states and clock (see #P0078)
!!!chips\82310.pdf p.71
!!!chips\api22.pdf p.33
 05h    (84031) ISA-bus command delays (see #P0079)
 06h    (84031) ISA-bus wait states (see #P0080)
 07h    (84031) ISA-bus clock select (see #P0081)
 08h    (84035) performance control (see #P0082)
 09h    (84035) miscellaneous control (see #P0083)
 0Ah    (84035) DMA clock select (see #P0084)
 10h    (84031) DRAM timing (see #P0085)
!!!chips\api22.pdf p.49
 11h    (84031) DRAM setup
 12h    (84031) block 0/1 DRAM configuration
 13h    (84031) block 2/3 DRAM configuration
 14h    (84031) DRAM block 0 start address
 15h    (84031) DRAM block 1 start address
 16h    (84031) DRAM block 2 start address
 17h    (84031) DRAM block 3 start address
 18h    (84031) video shadow / local bus control
 19h    (84031) shadow RAM read enable
 1Ah    (84031) shadow RAM write enable
 1Bh    (84031) ROMCS enable
 1Ch    (84031) soft reset / GATEA20

Bitfields for C&T 84035 IPC DMA controller configuration:
Bit(s)    Description    (Table P0078)
 7-6    reserved
 5-4    wait states for 16-bit DMA
    00 one (default)
    01 two
    10 three
    11 four
 3-2    wait states for 8-bit DMA (settings same as bits 5-4)
 1    disable one-cycle delay of MEMR# signal    after IOR#
 0    DMA clock (0 = BUSCLK/2 [default], 1 = BUSCLK)
SeeAlso: #P0077,#P0082

Bitfields for C&T 84031 ISA-bus command delays:
Bit(s)    Description    (Table P0079)
 !!!
SeeAlso: #P0077,#P0080,#P0081

Bitfields for C&T 84031 ISA-bus wait states:
Bit(s)    Description    (Table P0080)
 !!!
SeeAlso: #P0077,#P0079,#P0081

Bitfields for C&T 84031 ISA-bus clock select:
Bit(s)    Description    (Table P0081)
 !!!
SeeAlso: #P0077,#P0079,#P0080

Bitfields for C&T 84035 performance control:
Bit(s)    Description    (Table P0082)
 7    flush 486 cache during every slow-mode hold (keeps CPU from running out
      of L1 cache during holds)
 6-0    width of CPU hold pulse in BUSCLKs (0-127)
SeeAlso: #P0077,#P0078,#P0083

Bitfields for C&T 84035 miscellaneous control:
Bit(s)    Description    (Table P0083)
 7    floating-point error mode
    =0 generate IRQ13 internally on FERR#
    =1 use external logic to generate IRQ13
 6    keyboard interrupt mode
    =0 receive IRQ1 directly on IRQ1 pin
    =1 receive IRQ1 over control link
 5    disable GATEA20 emulation
    =0 A20 controlled solely by PORT 0092h
    =1 A20 is OR of PORT 0092h and emulated 8042 A20 control
 4    A20M#/TEST# function
    =0 pin is TEST# input
    =1 pin is A29M# output
 3    reserved
 2    enable 8254 Timer 1 refresh requests
    clearing this bit prevents problems that may be caused by a refresh
      request which occurs during a reset sequence
 1    use VL-bus-compatible preemptive arbitration for LGNT#
 0    deturbo mode (enable CPU holds as specified by performance-control
      register) (see #P0082)
Note:    the documentation says that bit 6 should remain clear
SeeAlso: #P0077,#P0082

Bitfields for C&T 84035 DMA clock select:
Bit(s)    Description    (Table P0084)
 7    disable internal real-time clock
 6-4    reserved (0)
 3-0    DMA clock
    0000 SCLK/10
    0001 SCLK/8
    0010 SCLK/6
    1000 SCLK/5 (use with 40 MHz SCLK)
    1001 SCLK/4 (use with 33 MHz SCLK)
    1010 SCLK/3 (use with 25 MHz SCLK)
    1011 SCLK/2.5 (for 20 MHz SCLK)
    1100 SCLK/2 (for 16 MHz SCLK)
    1101 SCLK/1.5
    else reserved
Note:    bits 3-0 should normally be set the same as register 07h bits 3-0
SeeAlso: #P0077

Bitfields for C&T 84031 DRAM timing:
Bit(s)    Description    (Table P0085)
 7-6    reserved (0)
 5
 4
 3
 2    !!!
 1    reserved (0)
 0    read timing
    0 = 3-2-2-2
    1 = 4-3-3-3
SeeAlso: #P0077,#P0086

Bitfields for C&T 84031 DRAM setup:
Bit(s)    Description    (Table P0086)
 7    enable DRAM parity
    (PORT 0061h bits 7 and 2 must also both be clear to enable parity)
 6-4    reserved (0)
 3-0    enable interleave for banks 3-0
    (enabling interleave doubles address range for bank; banks 0/2 and 1/3
      may be interleaved with each other)
SeeAlso: #P0077,#P0085
----------P00220023--------------------------
PORT 0022-0023 - OPTi 82C206 chipset - CONFIGURATION REGISTERS
Note:    many other OPTi chipsets integrate the functionality of the 82C206, and
      thus support the 82C206's configuration register (e.g. the
      82C558 from the Viper chipset)

0022  ?W  index for accesses to data port (set to 01h)
0023  RW  chip set data

Bitfields for OPTi 82C206 configuration register 01h:
Bit(s)    Description    (Table P0087)
 7-6    82C206 wait states
    00 1 SYSCLK
    01 2 SYSCLKs
    10 3 SYSCLKs
    11 4 SYSCLKs (default)
 5-4    number of wait states for 16-bit DMA cycles
    00 1 wait state (default)
    01 2 wait states
    10 3 wait states
    11 4 wait states
 3-2    number of wait states for 8-bit DMA cycles
    00 1 wait state (default)
    01 2 wait states
    10 3 wait states
    11 4 wait states
 1    enable early DMAMEMR#
 0    DMA speed
    0 SYSCLK/2
    1 SYSCLK
----------P00220023--------------------------
PORT 0022-0023 - Intel 82091AA Advanced Integrated Peripheral
Range:    PORT 0022h (X-Bus), PORT 0024h (X-Bus), PORT 026Eh (ISA), or
      PORT 0398h (ISA)
SeeAlso: PORT 0024h"82091AA",PORT 026Eh"82091AA",PORT 0398h"82091AA"

0022  ?W  configuration register index (see #P0088)
0023  RW  configuration register data

(Table P0088)
Values for Intel 82091AA configuration register index:
 00h    product ID (read-only)
    A0h Intel 82091AA
 01h    product revision (read-only) (see #P0089)
 02h    configuration 1 (see #P0090)
 03h    configuration 2 (see #P0091)
 04h-0Fh reserved
 10h    floppy-disk controller configuration (see #P0092)
 11h    floppy-disk controller power management/status (see #P0093)
 12h-1Fh reserved
 20h    parallel port configuration (see #P0094)
 21h    parallel port power management/status (see #P0095)
 22h-2Fh reserved
 30h    serial port A configuration (see #P0096)
 31h    serial port A power management/status (see #P0097)
 32h-3Fh reserved
 40h    serial port B configuration (see #P0096)
 41h    serial port B power management/status (see #P0097)
 42h-4Fh reserved
 50h    IDE configuration (see #P0098)
 51h-FFh reserved

Bitfields for Intel 82091AA product revision register:
Bit(s)    Description    (Table P0089)
 7-4    stepping number
 3-0    "dash"-number
SeeAlso: #P0088

Bitfields for Intel 82091AA configuration register 1:
Bit(s)    Description    (Table P0090)
 7    unused (0)
 6    supply voltage (read-only) (1 = 3.3V, 0 = 5.0V)
 5-4    configuration mode
    00 software motherboard
    01 software add-in
    10 extended hardware
    11 basic hardware
 3    configuration address (read-only)
    0 primary address (PORT 0022h for X-Bus, PORT 026Eh for ISA)
    1 secondary address (PORT 0024h for X-Bus, PORT 0398h for ISA)
 2-1    reserved
 0    power-down AIP's main clock circuitry
SeeAlso: #P0088,#P0091

Bitfields for Intel 82091AA configuration register 2:
Bit(s)    Description    (Table P0091)
 7-3    IRQ7-IRQ3 mode select
    0 = active high (ISA-compatible tri-state drive)
    1 = active low (EISA-compatible open-collector drive)
 2-0    reserved
SeeAlso: #P0088,#P0090

Bitfields for Intel 82091AA floppy-disk controller configuration register:
Bit(s)    Description    (Table P0092)
 7    four floppy drive support enabled (with external decoder)
 6-2    reserved
 1    FDC address
    0 = primary (03F0h)
    1 = secondary (0370h)
 0    enable FDC
SeeAlso: #P0088,#P0093

Bitfields for Intel 82091AA floppy-disk controller power management register:
Bit(s)    Description    (Table P0093)
 7-4    reserved
 3    enable FDC auto-powerdown on idle
 2    reset FDC
    (this bit must be pulsed, remaining high for at least 1.2 us)
 1    (read-only) FDC is idle
 0    power-down FDC
Note:    to restore FDC from explicit powerdown via bit 0, clear bit 0, then
      reset the FDC using bit 2 (hardware reset) or using a software reset
      (FDC's DOR bit 2 or DSR bit 7)
SeeAlso: #P0088,#P0092

Bitfields for Intel 82091AA parallel port configuration:
Bit(s)    Description    (Table P0094)
 7    FIFO threshold
    0 = 8 slots in each direction
    1 = one slot forward, 15 reverse
 6-5    parallel-port hardware mode
    00 ISA-compatible
    01 PS/2-compatible
    10 EPP
    11 ECP (read only -- ECP mode must be set via ECP Extended Control Reg)
 4    reserved
 3    IRQ select
    0 = IRQ5
    1 = IRQ7
 2-1    address select
    00 PORT 0378h-037Bh
    01 PORT 0278h-027Bh
    10 PORT 03BCh-03BEh (not for EPP mode)
    11 reserved
 0    enable parallel port
SeeAlso: #P0088,#P0095,#P0920,PORT 0678h"ECP"

Bitfields for Intel 82091AA parallel port power managment register:
Bit(s)    Description    (Table P0095)
 7-6    reserved
 5    FIFO overrun or underrun has occurred
    this bit is cleared by resetting the port via bit 2
 4    reserved
 3    enable auto-powerdown
 2    reset parallel port (pulse this bit; must remain high for 1.13 us)
 1    (read-only) parallel port is idle
 0    power-down parallel port
Note:    an explicit power-down may be canceled by either clearing bit 0 or
      pulsing bit 2 to reset the port
SeeAlso: #P0088,#P0094

Bitfields for Intel 82091AA serial port configuration:
Bit(s)    Description    (Table P0096)
 7    enable 2MHz MIDI clock for MIDI baud rate
 6-5    reserved
 4    IRQ select
    0 = IRQ3
    1 = IRQ4
 3-1    address select
    000 PORT 03F8h-03FFh
    001 PORT 02F8h-02FFh
    010 PORT 0220h-0227h
    011 PORT 0228h-022Fh
    100 PORT 0238h-023Fh
    101 PORT 02E8h-02EFh
    110 PORT 0338h-033Fh
    111 PORT 03E8h-03EFh
 0    enable serial port
Note:    although it is possible to configure both serial ports at the same
      address, this is not recommended because the 82091AA disables serial
      port B without placing it into powerdown mode
SeeAlso: #P0088,#P0097

Bitfields for Intel 82091AA serial port power management register:
Bit(s)    Description    (Table P0097)
 7-5    reserved
 4    enable test mode
    when enabled, and DLAB bit in LCR is set, the baud rate clock is output
      on the SOUTA pin
 3    enable auto-powerdown on idle
 2    reset serial port (should be pulsed, high for at least 1.13 us)
 1    (read-only) serial port is idle
 0    power-down serial port
Notes:    setting powerdown mode via bit 0 resets both receiver and transmitter,
      including the FIFOs, so software should check that port is idle
      before powering it down
    the serial port may be brought out of an explicit powerdown by either
      clearing bit 0 or pulsing bit 2
SeeAlso: #P0088,#P0096

Bitfields for Intel 82091AA IDE configuration:
Bit(s)    Description    (Table P0098)
 7-3    reserved
 2    enable both primary and secondary addresses
 1    address select (when bit 2 is clear)
    0 PORT 01F0h-01F7h and 03F6h (primary)
    1 PORT 0170h-0177h and 0376h (secondary)
 0    enable IDE interface
 !!!intel\29048603.pdf p.45
SeeAlso: #P0088,#P0092
----------P00220024--------------------------
PORT 0022-0024 - CHIPSET FROM PICO POWER, UMC or PCChips

0022  ?W  index for accesses to data port
0024  RW  chip set data
----------P00220024--------------------------
PORT 0022-0024 - OPTi 82C281/282/283 CHIPSETS - CONFIGURATION REGISTERS
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0099)
0024  RW  chip set data

(Table P0099)
Values for OPTi 82C281/82C282/82C283 configuration register index:
 10h    DRAM configuration register (see #P0100)
 11h    Shadow RAM control register (see #P0101)
 12h    Shadow RAM control register 2 (see #P0102)
 13h    Shadow RAM control register 3 (see #P0103)
 14h    miscellaneous control register (see #P0104)
 15h    cache control register (see #P0105)
 16h    cache control register 2 (see #P0106)

Bitfields for OPTi 82C281/282/283 DRAM configuration register:
Bit(s)    Description    (Table P0100)
 7-6    82C281/2 revision number (read-only)
 7    82C283 revision (0 = A, 1 = B)
 6    82C283A: reserved
    82C283B: DRAM is pipelined
 5    local DRAM read wait states
    82C281/2: 0=one, 1=two      82C283: 0=none, 1=one
 4    local DRAM write wait states
    82C281/2: 0=one, 1=two      82C283: 0=none, 1=one
 3-0    local DRAM memory configuration
    (val)    Bank0    Bank1    Bank2    Bank3
    0001    256K    256K    256K    256K
    0010    256K    256K    1M    -
    0011    256K    256K    1M    1M
    0100    256K    256K    4M    -
    0101    1M    -    -    -
    0110    1M    1M    -    -
    0111    1M    1M    1M    -
    1000    1M    1M    1M    1M
    1001    1M    4M    -    -
    1010    1M    1M    4M    -
    1011    4M    4M    -    -
    1100    4M    -    -    -  (82C283B only)
    1111    256K    256K    -    -
SeeAlso: #P0099

Bitfields for OPTi 82C281 shadow RAM control register:
Bit(s)    Description    (Table P0101)
 7    BIOS ROM F000-FFFF shadowing
    0 read-only from shadow RAM
    1 read from ROM, write to shadow RAM
 6    adapter ROM at E000-EFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by configuration register 12h
      (see #P0102)
 5    adapter ROM at D000-DFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by configuration register 12h
 4    adapter ROM at C000-CFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by configuration register 13h
      (see #P0103)
 3    shadow RAM Copy Enable control (C000-EFFF)
    0 write to expansion bus
    1 write to local DRAM
 2    shadow RAM E000-EFFF writeability
    0 read/write
    1 read-only
 1    shadow RAM D000-DFFF writeability
    0 read/write
    1 read-only
 0    shadow RAM C000-CFFF writeability
    0 read/write
    1 read-only
SeeAlso: #P0099,#P0102

Bitfields for OPTi 82C281 shadow RAM control register 2:
Bit(s)    Description    (Table P0102)
 7    enable EC00-EFFF
 6    enable E800-EBFF
 5    enable E400-E7FF
 4    enable E000-E3FF
 3    enable DC00-DFFF
 2    enable D800-DBFF
 1    enable D400-D7FF
 0    enable D000-D3FF
Note:    bits 7-4 are only in effect when register 11h bit 6 is set; bits 3-0
      are only in effect when register 11h bit 5 is set
SeeAlso: #P0099,#P0101,#P0103

Bitfields for OPTi 82C281 shadow RAM control register 3:
Bit(s)    Description    (Table P0103)
 7    enable CC00-CFFF
 6    enable C800-CBFF
 5    enable C400-C7FF
 4    enable C000-C3FF
 3-0    unused shadow RAM remap address; supplies bits 23-20 of
      address at which to map A000-BFFFF and D000-EFFF is not used
      for shadowing (except if this field is set to 0, the remapping
      is disabled)
SeeAlso: #P0099,#P0101,#P0102

Bitfields for OPTi 82C281 miscellaneous control register:
Bit(s)    Description    (Table P0104)
 7    allow F0000-F0FFF to be written even while F0000-FFFFF is
      write-protected ("Zenith mode")
 6    keyboard reset control
    =1 HLT must be executed before 82C281 generates CPU reset from
        keyboard controller Reset command
 5    master byte swap enable
 4    82C281/2: fast NMI request
    82C283A: reserved (0)
    82C283B: ATCLK setting (=0 from register 14h bit 0; =1 CLK/8)
 3    82C281/2/3A: reserved
    82C283B: on-board DRAM parity error enable
 2    enable slow refresh mode
    (every 95.5 us (281/282) or 63.6 us (283) instead of 15.9 us)
 1    enable turbo switch function
 0    clock select
    =0 ATCLK2 = CPUCLK2 / 6
    =1 ATCLK2 = CPUCLK2 / 4
SeeAlso: #P0099

Bitfields for OPTi 82C281/82C282 cache control register:
Bit(s)    Description    (Table P0105)
 7    enable cache
 6    reserved (0)
 5    enable posted write (82C281 only)
 4    ALL accesses are non-cacheable
 3    reserved (0)
 2-0    non-cacheable region size (see also #P0106)
    000  64K
    001 128K
    ...
    101  4M
    110  8M
    111 disabled
SeeAlso: #P0099,#P0106

Bitfields for OPTi 82C281/82C282 cache control register 2:
Bit(s)    Description    (Table P0106)
 7-0    starting address bits 23-16 of non-cacheable region
Note:    the specified starting address must be a multiple of the region size
SeeAlso: #P0099,#P0105
----------P00220024--------------------------
PORT 0022-0024 - OPTi 82C291/82C295 CHIPSETS - CONFIGURATION REGISTERS
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0107)
0024  RW  chip set data

(Table P0107)
Values for OPTi 82C291/82C295 configuration register index:
 20h    Revision/AT Bus configuration register (see #P0108)
 21h    System Control register (see #P0109)
 22h    DRAM configuration register (see #P0110)
 23h    ROM Chip Select Control register (see #P0111)
 24h    Shadow RAM control register E (see #P0112)
 25h    Shadow RAM control register D (see #P0113)
 26h    Shadow RAM control register C (see #P0114)
 27h    Shadow RAM Write Protect/Remap Area (see #P0115)
 28h    Cache Control register (see #P0116)
 29h    Cacheable Upper Bound register (see #P0117)
 2Ah    Non-Cacheable Segments register 1 (see #P0118)
 2Bh    Non-Cacheable Segments register 2 (see #P0119)
 2Ch    Non-Cacheable Segments register 3 (see #P0120)

Bitfields for OPTi 82C291/82C295 AT Bus configuration register:
Bit(s)    Description    (Table P0108)
 7-6    82C291/295 revision (read-only)
 5-4    back-to-back I/O recovery time
    00-11 = 3-6 ATCLKs between I/O accesses
 3    enable slow refresh mode
 2    enable hidden refresh
 1-0    AT clock selection
    00 ATCLK = CLK2 / 10
    01 ATCLK = CLK2 / 8
    10 ATCLK = CLK2 / 6
    11 ATCLK = CLK2 / 4
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 System Control register:
Bit(s)    Description    (Table P0109)
 7    AT bus master byte swap enabled
 6    ALE generation for each AT cycle
    0 a new ALE will be generated during bus conversion cycles
    1 multiple ALEs will be generated during bus conversion cycles
 5    keyboard fast reset emulation control
    0 enable, a "Halt" is required before a fast CPU reset is generated
    1 disable, fast CPU reset is generated directly after the "FE" I/O
      command to port 64h is decoded
 4    AT cycle additional wait state
    0 disable, standard AT cycle
    1 enable, inserts one extra wait state in standard AT bus cycle
 3-2    reserved
 1    local device ready control
    0 RDYI# input to the 82C291 will be synchronized and set as RDY# to
      the CPU one T-state delayed
    1 RDYI# input to the 82C291 will not be output to the CPU. RDY# from
      the local device must be directed to the 82C291 and the CPU
 0    system memory parity checking
    0 disable, no parity checking
    1 enable, will check parity
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 DRAM Configuration register:
Bit(s)    Description    (Table P0110)
 7-6    number of DRAM read cycle wait states
 5-4    number of DRAM write cycle wait states
 3-0    Banks 0 thru 3 DRAM configuration
    (val)    Bank0    Bank1    Bank2    Bank3
    0000    256K    256KB    -    -
    0001    256K    256K    256K    256K
    0010    256K    256K    1M    -
    0011    256K    256K    1M    1M
    0100    256K    256K    4M    -
    0101    1M    -    -    -
    0110    1M    1M    -    -
    0111    1M    1M    1M    -
    1000    1M    1M    1M    1M
    1001    1M    4M    -    -
    1010    1M    1M    4M    -
    1011    4M    -    -    -
    1100    4M    4M    -    -
    1101    reserved
    1110    reserved
    1111    reserved
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 ROM Chip Select Control register:
Bit(s)    Description    (Table P0111)
 7    enable ROM Chip Select for write cycles (to support flash ROMs)
 6    enable ROMCS# for 0F0000-0FFFFF segments
 5    enable ROMCS# for 0E8000-0EFFFF segments
 4    enable ROMCS# for 0E0000-0E7FFF segments
 3    enable ROMCS# for 0D8000-0DFFFF segments
 2    enable ROMCS# for 0D0000-0D7FFF segments
 1    enable ROMCS# for 0C8000-0CFFFF segments
 0    enable ROMCS# for 0C0000-0C7FFF segments
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Shadow RAM control register E:
Bit(s)    Description    (Table P0112)
 7    enable shadow RAM reads for EC000-EFFFF segments
 6    enable shadow RAM reads for E8000-EBFFF segments
 5    enable shadow RAM reads for E4000-E7FFF segments
 4    enable shadow RAM reads for E0000-E3FFF segments
 3    enable shadow RAM writes for EC000-EFFFF segments
 2    enable shadow RAM writes for E8000-EBFFF segments
 1    enable shadow RAM writes for E4000-E7FFF segments
 0    enable shadow RAM writes for E0000-E3FFF segments
Note:    OPTi documentation incorrectly states the segment range for bits 5
      and 1 as E4000-E7000.
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Shadow RAM control register D:
Bit(s)    Description    (Table P0113)
 7    enable shadow RAM reads for DC000-DFFFF segments
 6    enable shadow RAM reads for D8000-DBFFF segments
 5    enable shadow RAM reads for D4000-D7FFF segments
 4    enable shadow RAM reads for D0000-D3FFF segments
 3    enable shadow RAM writes for DC000-DFFFF segments
 2    enable shadow RAM writes for D8000-DBFFF segments
 1    enable shadow RAM writes for D4000-D7FFF segments
 0    enable shadow RAM writes for D0000-D3FFF segments
Note:    OPTi documentation incorrectly states the segment range for bits 5
      and 1 as D4000-D7000.
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Shadow RAM control register C:
Bit(s)    Description    (Table P0114)
 7    enable shadow RAM reads for CC000-CFFFF segments
 6    enable shadow RAM reads for C8000-CBFFF segments
 5    enable shadow RAM reads for C4000-C7FFF segments
 4    enable shadow RAM reads for C0000-C3FFF segments
 3    enable shadow RAM writes for CC000-CFFFF segments
 2    enable shadow RAM writes for C8000-CBFFF segments
 1    enable shadow RAM writes for C4000-C7FFF segments
 0    enable shadow RAM writes for C0000-C3FFF segments
Note:    OPTi documentation incorrectly states the segment range for bits 5
      and 1 as C4000-C7000.
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Shadow RAM Write Protect/Remap Area:
Bit(s)    Description    (Table P0115)
 7    enable Write Protect for F0000-FFFFF segments
 6    enable Write Protect for E0000-EFFFF segments
 5    enable Write Protect for D0000-DFFFF segments
 4    enable Write Protect for C0000-CFFFF segments
 3-0    DRAM remap starting address, bits 23-20
    0000  disabled, no mapping
    0001  1M
    0010  2M
    ...
    1111 15M
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Cache Control register:
Bit(s)    Description    (Table P0116)
 7    enable write-back cache controller operation
 6    enable DRAM performance mode
    this bit should not be enabled unless external cache is disabled
      (intended to optimize DRAM performance)
 5    enable all memory accesses no-cacheable mode
 4    enable 640K-1M area no-cacheable mode
 3-2    cache timing control bits
    00 invalid
    01 0 wait state cache write w/o CAWE# extended, use when 8K*8 SRAMs
    10 1 wait state cache write hit
    11 0 wait state cache write hit with CAWE# extended when 32K*8 SRAMs
 1-0    cache size/cacheable DRAM
    00  16K /  2M
    01  32K /  4M
    10  64K /  8M
    11 128K / 16M
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Cacheable Upper Bound register:
Bit(s)    Description    (Table P0117)
 7-4    reserved
 3-0    cacheable upper bound address, bits 23-20
    0000  feature disabled
    0001  1M
    0010  2M
    ...
    1111 15M
SeeAlso: #P0107

Bitfields for OPTi 82C291/82C295 Non-Cacheable Segments register 1:
Bit(s)    Description    (Table P0118)
 7    enable non-cacheable segment A
 6-4    size of no-cacheable memory segment A
    000  64K
    001 128K
    010 256K
    011 512K
    100   1M
    101   2M
    110   4M
    111   8M
 3    enable non-cacheable segment B
 2-0    size of no-cacheable memory segment B (same values as bits 6-4)
SeeAlso: #P0107,#P0119

Bitfields for OPTi 82C291/82C295 Non-Cacheable Segments register 2:
Bit(s)    Description    (Table P0119)
 7-0    address bits 23-16 for starting address of non-cacheable memory
      segment A
SeeAlso: #P0107,#P0118,#P0120

Bitfields for OPTi 82C291/82C295 Non-Cacheable Segments register 3:
Bit(s)    Description    (Table P0120)
 7-0    address bits 23-16 for starting address of non-cacheable memory
      segment B
SeeAlso: #P0107,#P0118,#P0119
----------P00220024--------------------------
PORT 0022-0024 - OPTi 82C381/82C382 CHIPSETS - CONFIGURATION REGISTERS
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0121)
0024  RW  chip set data

(Table P0121)
Values for OPTi 82C381/82C382 configuration register index:
 00h    clock selects (see #P0122)
 01h    reset control (see #P0123)
 10h    remapping address (see #P0124)
 11h    shadow RAM (see #P0125)
 12h    memory enable (see #P0126)
 13h    bank configuration (see #P0127)
 14h    DRAM configuration (see #P0128)
 15h    video adapter shadow (see #P0129)
 16h    fast GateA20 (see #P0130)
 17h    cache configuration (see #P0131)
 18h    non-cacheable block 1 size (see #P0132)
 19h    non-cacheable block 1 address (see #P0133)
 1Ah    non-cacheable block 2 size (see #P0132)
 1Bh    non-cacheable block 2 address (see #P0133)
 1Ch    cacheable area (see #P0134)
Note:    registers 00h and 01h address the 82C381, the remaining registers
      address the 82C382
SeeAlso: #P0189

Bitfields for OPTi 82C381/82C382 clock selects:
Bit(s)    Description    (Table P0122)
 7-6    cache controller enable
    00 cache controller disabled (default)
    01 cache controller disabled; PPCS#, SPCS#, NPCS# signals are
          active if selected
    10 external cache controller installed
    11 on-chip cache controller installed
 5    hot CPU reset (low->high transition generates reset)
 4    enable ATCLK stretch
 3    turbo clock
    =0 CLKIN is CPU clock
    =1 HIGH pin selected clock (HIGH=0: CLKIN, HIGH=1: ICLK)
 2-1    ICLK clock select
    00 CLKIN/4 (default)
    01 CLKIN/3
    10 CLKIN/2
    11 reserved
 0    master byte swap enable (default = 0)
SeeAlso: #P0121,#P0123

Bitfields for OPTi 82C381/82C382 reset control:
Bit(s)    Description    (Table P0123)
 7-2    reserved
 1    RESET3 control
    =1 generate RESET3 on RESET2 only after a HLT instruction
    =0 generate RESET3 immediately on RESET2 (default)
 0    activate cache controller FLUSH# pin (default = 1)
SeeAlso: #P0121,#P0122,#P0124

Bitfields for OPTi 82C381/82C382 remapping address:
Bit(s)    Description    (Table P0124)
 7-5    reserved
 4    enable remapping
 3-0    remap address range, bits 23-20
    0000  no mapping
    0001  1M
    0010  2M
    ...
    1111 15M
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 shadow RAM control:
Bit(s)    Description    (Table P0125)
 7    BIOS ROM at F0000-FFFFF Shadowing
    0 read only from shadow RAM
    1 read from ROM, write to shadow RAM
 6    ROM at D0000-DFFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by configuration register 12h
 5    Adaptor ROM at E0000-EFFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by configuration register 12h
 4    write-protect shadow RAM at D0000h-DFFFFh (default = not protected)
 3    write-protect shadow RAM at E0000h-EFFFFh
 2    enable Timeout precharge counter
 1-0    reserved
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 memory enable:
Bit(s)    Description    (Table P0126)
 7    enable EC000-EFFFF
 6    enable E8000-EBFFF
 5    enable E4000-E7FFF
 4    enable E0000-E3FFF
 3    enable DC000-DFFFF
 2    enable D8000-DBFFF
 1    enable D4000-D7FFF
 0    enable D0000-D3FFF
Note:    0 = disable Shadow RAM (default), 1 = enable Shadow RAM
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 memory bank configuration:
Bit(s)    Description    (Table P0127)
 7    Reserved
 6-4    Bank0 and Bank1 configuration
    (val)    Bank0     Bank1
    000    256K     -
    001    256K     256K
    010    256K     1M
    011    1M     256K
    100    1M     -
    101    1M     1M
    110    -     -
    111    256K     -
 3    reserved
 2-0    Bank2 and Bank3 configuration
    (val)    Bank2     Bank3
    000    256K     -
    001    256K     256K
    010    -     -
    011    1M     256K
    100    1M     -
    101    1M     1M
    11X    -     -
SeeAlso: #P0121,#P0128

Bitfields for OPTi 82C381/82C382 DRAM configuration:
Bit(s)    Description    (Table P0128)
 7,6    number of read cycle wait states (default = 01)
 5    write cycle wait state
    0 = 0 wait
    1 = 1 wait (default)
 4-0    reserved
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 video adapter shadow:
Bit(s)    Description    (Table P0129)
 7    reserved
 6    copy enable for C0000-EFFFF
    0 write to AT Channel (default)
    1 write to local DRAM
 5    Shadow RAM at C0000-CFFFF writability
    0 read/write (default)
    1 read only
 4    ROM at C0000-CFFFF
    0 disable shadow RAM
    1 shadow RAM selectively enabled by Bits<0:3> (default)
 3    enable Shadow RAM at CC000-CFFFF
 2    enable Shadow RAM at C8000-CbFFF
 1    enable Shadow RAM at C4000-C7FFF
 0    enable Shadow RAM at C0000-C3FFF
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 fast GateA20 control:
Bit(s)    Description    (Table P0130)
 7-4    Reserved
 3    Fast GateA20 Control
    0 Signal controled by GATEA20 signal from Keyboard Controler
    1 CPUA20 enabled onto GA20
 2-0    reserved
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 cache configuration:
Bit(s)    Description    (Table P0131)
 7    force NCA* Output Pin low
    if this bit is clear, it has no effect on NCA* Output Pin
 6    enable Cache
 5    write-through cache (Note: this bit must be set)
 4-3    line size
    00  4 bytes
    01  8 bytes
    10  16 bytes
    11  reserved
 2-0    reserved
SeeAlso: #P0121

Bitfields for OPTi 82C381/82C382 non-cacheable block size:
Bit(s)    Description    (Table P0132)
 7-5    block size
    000 64K
    001 128K
    010 256K
    011 512K
    100 1M
    101 4M (block 1 only)
    101 reserved (block 2 only)
    110 8M (block 1 only)
    110 reserved (block 2 only)
    111 disabled (default)
 4-0    reserved (0)
SeeAlso: #P0121,#P0131,#P0133

Bitfields for OPTi 82C381/82C382 non-cacheable block address:
Bit(s)    Description    (Table P0133)
 7-0    bits 23-16 of non-cacheable block's address
Note:    the selected address must be a multiple of the block size
      selected by register 18h/1Ah
SeeAlso: #P0121,#P0132,#P0134

Bitfields for OPTi 82C381/82C382 cacheable area:
Bit(s)    Description    (Table P0134)
 7-4    cacheable address range
    0000 16M
    0001 1M
    0010 2M
    0011 3M
    ...
    1111 15M
 3    256K remapped area is cacheable
 2-0    reserved
SeeAlso: #P0121
----------P00220024--------------------------
PORT 0022-0024 - OPTi 82C463MV CHIPSET - CONFIGURATION REGISTERS
Desc:    the 82C463MV contains a memory control unit (MCU), an AT Bus
      Control Unit (BCU), a Power Management Unit (PMU), data
      buffers and a 82C206 type IPC (without real time clock)
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0135)
0024  RW  chip set data

(Table P0135)
Values for OPTi 82C463MV configuration register index:
 30h    general control 1 (see #P0136)
 31h    general control 2 (see #P0137)
 32h    shadow RAM control 1 (see #P0138)
 33h    shadow RAM control 2 (see #P0139)
 34h    DRAM size (see #P0140)
 35h    DRAM timing and caching control (see #P0141)
 36h    shadow RAM control 3 (see #P0142)
 37h    D000h and E000h segment access control (see #P0143)
 38h    non-cacheable block 1 size, controls and address bit A24 (see #P0144)
 39h    non-cacheable block 1 address bits A23-A16
 3Ah    non-cacheable block 2 size and address bit A24 (see #P0145)
 3Bh    non-cacheable block 2 address bits A23-A16
 3Ch-3Fh    reserved
 40h    PMU control 1 (see #P0146)
 41h    PMU control 2: doze timer (see #P0147)
 42h    PMU control 3: other timers (see #P0148)
 43h    PMU control 4 (see #P0149)
 44h    LCD timer count (should not be loaded with a value <5)
 45h    disk timer count (should not be loaded with a value <5)
 46h    keyboard timer count (should not be loaded with a value <5)
 47h    GNR_ACCESS timer count (should not be loaded with a value <5)
 48h    GNR_ACCESS I/O base address (lines A8-A1, A0 is a "don't care")
 49h    GNR_ACCESS control and I/O base address line A9 (see #P0150)
 4Ah    CSG0# base address (lines A8-A1, A0 is a "don't care")
 4Bh    CSG0# control and base address line A9 (see #P0151)
 4Ch    CSG1# base address (lines A8-A1, A0 is a "don't care")
 4Dh    CSG1# control and base address line A9 (see #P0152)
 4Eh    idle timer control (see #P0153)
 4Fh    idle timer count (should not be loaded with a value <5)
 50h    suspend/resume control (see #P0154)
 51h    beeper/sequencer control (see #P0155)
 52h    PMU general-purpose storage 1
 53h    PMU general-purpose storage 2
 54h    PMU Periferal Power (PPWR) control 1 (see #P0156)
 55h    PMU Periferal Power (PPWR) control 2 (see #P0157)
 56h    PIO control 1 (see #P0158)
 57h    PIO control 2 (see #P0159)
 58h    PMU event control 1 (see #P0160)
 59h    PMU event control 2 (see #P0161)
 5Ah    PMU event control 3 (see #P0162)
 5Bh    PMU event control 4 (see #P0163)
 5Ch    SMI source (low) (see #P0164)
 5Dh    SMI source (high) (see #P0165)
 5Eh    clock stretching control (see #P0166)
 5Fh    resume interrupt control (see #P0167)
 60h    software sequencer address (write only)
 61h    debounce control (see #P0168)
 62h    doze-mode IRQ selects (see #P0169)
 63h    idle timer IRQ selects (see #P0170)
 64h    PMI#6 IRQ select (see #P0171)
 65h    doze-mode configuration (see #P0172)
 66h    suspend control (see #P0173)
 67h    CPU frequency (see #P0174)
 68h    timer clock source (see #P0175)
 69h    R_TIMER count (should not be loaded with a value <5)
 6Ah    resume IRQ selects (see #P0176)
 6Bh    resume sources (see #P0177)
 6Ch-6Fh    TMP0 - TMP3

Bitfields for 82C463MV general control 1 (register 30h):
Bit(s)    Description    (Table P0136)
 7-6    chipset revision number (read only)
 5    MASTER#/RI pin function (RI = modem Ring Indicator)
    =1 RI (default)
    =0 MASTER#
 4    enable turbo VGA
 3    enable global relocation/translation for SMI addresses (see also
      register 31h bit 4 at #P0137)
 2    enable extra wait state in AT cycle
 1    fast reset control
      =1 does not require Halt instruction
      =0 requires Halt instruction before generation of CPURST (SRESET
           if Intel SL Enhanced or Cyrix Cx486S/S2 CPUs
 0    reserved (0)
SeeAlso: #P0135

Bitfields for 82C463MV general control 2 (register 31h):
Bit(s)    Description    (Table P0137)
 7    enable master byte swap
 6    reserved, read-only (1)
 5    disable parity check
 4    Dynamic SMI relocation
      if no SMI sequence is running
        =1 allow relocation of addresses from the CPU in the 3000h/4000h
           segment to the B000h/A000h SMI memory space
        =0 disable relocation
      if SMI sequence is running (qualified by SMIACT#)
        =1 allow data accesses to the 3000h and 4000h segments
        =0 relocate all accesses in the 3000h/4000h segment to the
           B000h/A000h SMI segment (normal operation)
      if SMI sequence is running (qualified by SMIADS#)
        =1 not allowed
        =0 for a SMIADS# cycle, relocate all accesses in the 6000h/7000h
           segment to the A000h/B000h SMI segment
           for a normal ADS# operation, there is no relocation
 3    EC000h-EFFFFh access control
    if register 36h bit 6=0
      =1 R/W from ROMCS#
      =0 R/W from AT-Bus
    if register 36h bit 6=1
      =1 Read from ROMCS# if not shadowed (see register 33h bits 7-4),
        write to DRAM
      =0 Read from AT-Bus if not shadowed (see register 33h bits 7-4),
        write to DRAM
 2    E8000h-EBFFFh access control (see bit 3)
 1    E4000h-E7FFFh access control (see bit 3)
 0    E0000h-E3FFFh access control (see bit 3)
SeeAlso: #P0135,#P0139,#P0142

Bitfields for 82C463MV shadow RAM control 1 (register 32h):
Bit(s)    Description    (Table P0138)
 7    segment F000h access control
      =1 read from ROMCS#, write to ROMCS# (if register 36h bit 7=1)
         or DRAM (if register 36h bit 7=0)
      =0 read from DRAM and write protect (enable shadowing)
 6-5    reserved (1)
 4    write protect segment D000h
 3    write protect segment E000h
 2    reserved, read-only (1)
 1    reserved (0)
 0    ALE control
      =1 single ALE during bus conversion
      =0 multiple ALE
SeeAlso: #P0135,#P0142,#P0139

Bitfields for 82C463MV shadow RAM control 2 (register 33h):
Bit(s)    Description    (Table P0139)
 7    enable shadowing for EC000h-EFFFFh
 6    enable shadowing for E8000h-EBFFFh
 5    enable shadowing for E4000h-E7FFFh
 4    enable shadowing for E0000h-E3FFFh
 3    enable shadowing for DC000h-DFFFFh
 2    enable shadowing for D8000h-DBFFFh
 1    enable shadowing for D4000h-D7FFFh
 0    enable shadowing for D0000h-D3FFFh
SeeAlso: #P0135,#P0138

Bitfields for 82C463MV DRAM size (register 34h):
Bit(s)    Description    (Table P0140)
 7-4    DRAM Bank 0 and 1 Size
    0000 256K, unused
    0001 256K, 256K
    0010 256K, 1M
    0011 256K, 4M
    0100 512K, unused
    0101 512K, 512K
    0110 512K, 1M
    0111 512K, 4M
    1000 1M, unused
    1001 1M, 1M
    1010 1M, 4M
    1011 4M, 1M
    1100 4M, unused
    1101 4M, 4M
    1110 1M, 2M
    1111 both unused
 3-0    DRAM Bank 2 and 3 Size
    0000 1M, unused
    0001 1M, 1M
    0010 1M, 4M
    0011 4M, 4M
    0100 4M, unused
    0101 both unused
    0110 1M, 2M
    0111 512K, 512K
    10xx both unused
    110x both unused
    1110 2M, unused
    1111 2M, 2M (default)
SeeAlso: #P0135

Bitfields for 82C463MV DRAM timing and caching control (register 35h):
Bit(s)    Description    (Table P0141)
 7-6    DRAM read wait states
    00 = 0 wait states, burst mode 2-1-1-1
    01 = 1 wait state, burst mode 3-1-1-1
    10 = 1 wait state, burst mode 3-2-2-2
    11 = 2 wait states, burst mode 4-3-3-3 (default)
 5-4    DRAM write wait states
    00 = 0 wait states
    01 = 1 wait state
    10 = 2 wait states
    11 = reserved (default)
 3    MP2/STRAP2 status (read-only)
    =1 1X Clock
    =0 2X Clock
 2    disable caching of F000h segment (this bit is effective only when
      register 32h bit 7 =0)
 1    global DRAM cache control (1=disable, default)
 0    disable caching of C0000h-C7FFFh (default)
SeeAlso: #P0135,#P0138

Bitfields for 82C463MV shadow RAM control 3 (register 36h):
Bit    Description    (Table P0142)
 7    segment F000h write control
    =1 write to ROMCS#
    =0 write to DRAM
    don't care if register 32h bit 7=0
 6    C0000h-EFFFFh control
    =1 read from AT-Bus or ROMCS# (if ROMCS# is enabled to that block),
      write to DRAM
    =0 R/W from AT bus or ROMCS# (if ROMCS# is enabled to that block)
 5    write protect segment C000h
 4    reserved (1)
 3    enable shadowing for CC000h-CFFFFh
 2    enable shadowing for C8000h-CBFFFh
 1    enable shadowing for C4000h-C7FFFh
 0    enable shadowing for C0000h-C3FFFh
SeeAlso: #P0135,#P0138

Bitfields for 82C463MV D000h and E000h segments access control (register 37h):
Bit    Description    (Table P0143)
 7    DC000h-DFFFFh access control
    if register 36h bit 6=1
        =1 read from ROMCS# if not shadowed, write to DRAM
        =0 read from AT-Bus if not shadowed, write to DRAM
    if register 36h bit 6=0
        =1 R/W from ROMCS#
        =0 R/W from AT-Bus
 6    D8000h-DBFFFh access control (see bit 7)
 5    D4000h-D7FFFh access control (see bit 7)
 4    D0000h-D3FFFh access control (see bit 7)
 3    disable caching for EC000h-EFFFFh (default)
 2    disable caching for E8000h-EBFFFh (default)
 1    disable caching for E4000h-E7FFFh (default)
 0    disable caching for E0000h-E3FFFh (default)
SeeAlso: #P0135,#P0142

Bitfields for non-cacheable block 1 size, control and A24 (register 38h):
Bit(s)    Description    (Table P0144)
 7-5    size of non-cacheable memory block 1
    000 64K
    001 128K
    010 256K
    011 1M
    1xx disabled (default)
 4    CC000h-CFFFFh access control
    if register 36h bit 6=1
        =1 read from ROMCS# if not shadowed, write to DRAM
        =0 read from AT-Bus if not shadowed, write to DRAM
    if register 36h bit 6=0
        =1 R/W from ROMCS#
        =0 R/W from AT-Bus
 3    C8000h-CBFFFh access control (see bit 4)
 2    C4000h-C7FFFh access control (see bit 4)
 1    C0000h-C3FFFh access control (see bit 4)
 0    address bit A24 of non-cacheable memory block 1
SeeAlso: #P0135,#P0142

Bitfields for non-cacheable block 2 size and A24 (register 3Ah):
Bit(s)    Description    (Table P0145)
 7-5    size of non-cacheable memory block 2
    000 64K
    001 128K
    010 256K
    011 1M
    1xx disabled (default)
 4    unused
 3    enable internal HLDA latch during stop clock (must be disabled
      before DMA transfers are performed)
 2    reserved (1)
 1    unused
 0    address bit A24 of non-cacheable memory block 2
SeeAlso: #P0135

Bitfields for 82C463MV PMU control 1 (register 40h):
Bit    Description    (Table P0146)
 7    Reset/SMI indication (read-only)
    =1 the last read or fetch from address XXXFFFF0h was a SMIADS#
         cycle
    =0 the last read or fetch from address XXXFFFF0h was a regular
         ADS# cycle
 6    divide global timer by 4
 5    LLOWBAT polarity selector
    =1 low active
    =0 high active
 4    LOWBAT polarity selector (see bit 5)
 3    SQWIN input clock frequency
    =1 128KHz
    =0 32KHz
 2    external EPMI2 pin polarity
    =1 active low
    =0 active high
 1    external EPMI1 pin polarity (see bit 2)
 0    send reset pulse during resume
Note:    for 1X clock with Intel SL Enhanced CPU, bit 6 must be =1
SeeAlso: #P0135,#P0147,#P0148

Bitfields for 82C463MV PMU control 2 (doze timer, register 41h):
Bit(s)    Description    (Table P0147)
 7-5    hardware doze time-out selector
    101 512 ms
    110 2 sec
    111 8 sec
 4-2    hardware doze-mode CPU clock selector
    000 CPUCLK/1
    001 CPUCLK/2
    010 CPUCLK/4
    011 CPUCLK/8 (should be used during CPU stop clock only)
    100 CPUCLK/16 (should be used during CPU stop clock only)
    101 CPUCLK/3
    110 reserved
    111 reserved
 1    enable LCD_ACCESS, KBD_ACCESS, DSK_ACCESS access to auto trigger
      the hardware doze timer
 0    disable hardware doze-mode (enable APM doze-mode support)
SeeAlso: #P0135,#P0146,#P0148

Bitfields for 82C463MV PMU control 3 (timers other than doze, register 42h):
Bit(s)    Description    (Table P0148)
 7-6    clock source for general-purpose timer
    00 SQW0
    01 SQW1
    10 SQW2
    11 SQW3
 5-4    clock source for keyboard timer (see bits 7-6)
 3-2    clock source for disk timer (see bits 7-6)
 1-0    clock source for LCD timer (see bits 7-6)
SeeAlso: #P0135,#P0147,#P0149

Bitfields for 82C463MV PMU control 4 (register 43h):
Bit(s)    Description    (Table P0149)
 7    disable monitoring of PORT 3B0h-3DFh
 6    disable monitoring of memory range A0000h-BFFFFh
 5-4    LOWBAT pin sample rate
    if register 40h bit 6 =1
        00 32 seconds
        01 64 seconds
        10 128 seconds
        11 reserved
    if register 40h bit 6     =0
        00 8 seconds
        01 16 seconds
        10 32 seconds
        11 reserved
 3    reserved (0)
 2-0    AT clock select
    000 OSCCLK2/8
    001 OSCCLK2/6
    010 OSCCLK2/4
    011 OSCCLK2/3
    100 OSC14/2 (7.2 MHz)
    111 stop
SeeAlso: #P0135,#P0146,#P0149,#P0150

Bitfields for 82C463MV GNR_ACCESS control, I/O base address line A9 (reg. 49h):
Bit(s)    Description    (Table P0150)
 7    GNR_ACCESS I/O base address bit A9
 6    enable compare in WRITE cycle
 5    enable compare in READ cycle
 4-0    I/O address A5-A1 mask bits. For each bit =1, the corresponding bit
      in register 48h is not compared (this is used to determine I/O
      address block size)
SeeAlso: #P0135,#P0149

Bitfields for 82C463MV CSG0# control and base address line A9 (register 4Bh):
Bit(s)    Description    (Table P0151)
 7    Programmable Chip Select 0 (CSG0#) - I/O base address line A9
 6    enable CSG0# for I/O write cycles
 5    enable CSG0# for I/O read cycles
 4    =1 CSG0# active before ALE
    =0 CSG0# active just like I/O command pulse
 3-0    I/O address A4-A1 mask bits. For each bit =1, the corresponding bit
      in register 4Ah (bits 4-1) is not compared (this is used to
      determine I/O address block size)
SeeAlso: #P0135,#P0152

Bitfields for 82C463MV CSG1# control and base address line A9 (register 4Dh):
Bit(s)    Description    (Table P0152)
 7    Programmable Chip Select 1 (CSG1#) - I/O base address line A9
 6    enable CSG1# for I/O write cycles
 5    enable CSG1# for I/O read cycles
 4    =1 CSG1# active before ALE
    =0 CSG1# active just like I/O command pulse
 3-0    I/O address A4-A1 mask bits. For each bit =1, the corresponding bit
    in register 4Ch (bits 4-1) is not compared (this is used to
    determine I/O address block size)
SeeAlso: #P0135,#P0151

Bitfields for OPTi 82C463MV idle timer control (register 4Eh):
Bit    Description    (Table P0153)
 7    CSG1 access
 6    CSG0 access
 5    LPT access (it refers to PORT 378h-37Fh, PORT 278h-27Fh and
      PORT 3BCh-3BFh)
 4    COM access (it refers to PORT 3F8h-3FFh and PORT 2F8h-2FFh)
 3    GNR_ACCESS
 2    KBD_ACCESS
 1    DSK_ACCESS
 0    LCD_ACCESS
Note:    If a bit is =1, the corresponding access will reload IDLE_TIMER
      otherwise not.
SeeAlso: #P0135

Bitfields for 82C463MV suspend/resume control (register 50h):
Bit    Description    (Table P0154)
 7    software generation of SMI (enabled by bit 7 of register 59h)
      writing 1 asserts SMI to CPU to start SMM operation
      writing 0 clears the SMI (the SMI routine must clear this bit)
 6    reserved (0)
 5    IRQ8 active level
    =1 high active
    =0 low active
 4    disable the internal 14.3MHz clock (to conserve power)
 3    start doze-mode / read DOZE_TIMER status
    write: start APM doze-mode
        =1 start doze-mode (if register 40h bit 0 =1)
        =0 no effect
    read: hardware DOZE_TIMER time-out status bit
        =1 hardware DOZE_TIMER has timed out
        =0 hardware DOZE_TIMER still counting
 2    Ready To Resume (RTR), read-only
 1    PMU mode (read-only)
    =1 suspend-mode still active
    =0 all other modes
 0    start suspend-mode (write only)
    =1 start suspend-mode
    =0 no effect
SeeAlso: #P0135,#P0146,#P0161

Bitfields for 82C463MV beeper/sequencer control (register 51h):
Bit(s)    Description    (Table P0155)
 7-2    sequencer base address translated-to A17-A12 (A19-A18 are always 1
      during this operation)
 1-0    beeper control (independent from PORT 61h)
    if register 40h bit 6 =1
        00 no action
        01 1KHz
        10 off
        11 2KHz
    if register 40h bit 6 =0
        00 no action
        01 4KHz
        10 off
        11 8KHz
SeeAlso: #P0135,#P0146

Bitfields for 82C463MV PMU Periferal Power (PPWR) control 1 (register 54h):
Bit(s)    Description    (Table P0156)
 7-4    write mask of PPWR low nibble
    =1 enable write on corresponding bit
    =0 write disable
 3-0    read/write data bits for PPWR (low nibble)
SeeAlso: #P0135,#P0157

Bitfields for 82C463MV PMU Periferal Power (PPWR) control 2 (register 55h):
Bit(s)    Description    (Table P0157)
 7-4    write mask of PPWR high nibble
    =1 enable write on corresponding bit
    =0 write disable
 3-0    read/write data bits for PPWR (high nibble) (default =1)
SeeAlso: #P0135,#P0156

Bitfields for OPTi 82C463MV PIO control 1 (register 56h):
Bit(s)    Description    (Table P0158)
 7-4    write mask of PIO bits 3-0
    =1 enable write on corresponding bit
    =0 write disable
 3-0    read/write data bits for PIO
SeeAlso: #P0135,#P0159,#P0173

Bitfields for OPTi 82C463MV PIO control 2 (register 57h):
Bit    Description    (Table P0159)
 7    enable refresh (BIOS must set this bit to 1 after power up)
 6    enable interrupts to generate PMI #6 (see also #P0167,#P0171)
 5    disable monitoring floppy drive accesses
 4    disable monitoring hard drive accesses
 3    PIO3/STPGNT# pin direction
    =1 output
    =0 input
 2    PIO2/CPUSPD pin direction (see bit 3)
 1    PIO1/NOWS# pin direction (see bit 3)
 0    PIO0 pin direction (see bit 3)
SeeAlso: #P0135,#P0158

Bitfields for OPTi 82C463MV PMU event control 1 (register 58h):
Bit(s)    Description    (Table P0160)
 7-6    LOWBAT PMI #3 configuration
    00 disable
    01 sequencer
    10 reserved
    11 SMI
 5-4    EPMI2 PMI #2 configuration (see bits 7-6)
 3-2    EPMI1 PMI #1 configuration (see bits 7-6)
 1-0    LLOWBAT PMI #0 configuration (see bits 7-6)
SeeAlso: #P0135

Bitfields for OPTi 82C463MV PMU event control 2 (register 59h):
Bit(s)    Description    (Table P0161)
 7    global software SMI enable (see also bit 7 of register 50h at #P0154)
 6    reload timers during a resume sequence
 5-4    resume or INTR PMI #6 and Suspend PMI #7 configuration
    00 disable
    01 sequencer
    10 reserved
    11 SMI
 3-2    R_TIMER PMI #5 configuration (see bits 5-4)
 1-0    IDLE_TIMER PMI #4 configuration (see bits 5-4)
SeeAlso: #P0135

Bitfields for OPTi 82C463MV PMU event control 3 (register 5Ah):
Bit(s)    Description    (Table P0162)
 7-6    GNR_TIMER time out PMI #11 and access PMI #15 configuration
    00 disable
    01 sequencer
    10 reserved
    11 SMI
 5-4    KBD_TIMER time out PMI #10 and access PMI #14 cfg (see bits 7-6)
 3-2    DSK_TIMER time out PMI #9 and access PMI #13 cfg (see bits 7-6)
 1-0    LCD_TIMER time out PMI #8 and access PMI #12 cfg (see bits 7-6)
SeeAlso: #P0135,#P0163

Bitfields for OPTi 82C463MV PMU event control 4 (register 5Bh):
Bit    Description    (Table P0163)
 7    IRQ15 SMI select
    =1 enable SMI select (SMI internally connected to IRQ15) and
      disable IRQ15 hardware pin function
    =0 disable SMI select (enable IRQ15 pin function as normal)
 6    disable all SMI
 5    enable sequencer
 4    SMI Type
    =0 Intel style SMI (SMM identified by SMIACT#)
    =1 AMD DXLV or Cyrix style SMI (SMM identified by SMIADS#)
    Note:    for Intel-style SMI, the 3000h/4000h segments will relocate to
          B000h/A000h when in SMM; for AMD/Cyrix, the 7000h/6000h
          segments will relocate to B000h/A000h when in SMM
 3    enable PMI source #15
 2    enable PMI source #14
 1    enable PMI source #13
 0    enable PMI source #12
SeeAlso: #P0135,#P0162,#P0164

Bitfields for OPTi 82C463MV SMI source (low) (register 5Ch):
Bit    Description    (Table P0164)
 7    PMI #7 - SUSPEND
 6    PMI #6 - RESUME or INTR
 5    PMI #5 - R_TIMER time out
 4    PMI #4 - IDLE_TIMER time out
 3    PMI #3 - LOWBAT pin
 2    PMI #2 - EPMI2 pin (external PMI source)
 1    PMI #1 - EPMI1 pin (external PMI source)
 0    PMI #0 - LLOWBAT pin
SeeAlso: #P0135,#P0165

Bitfields for OPTi 82C463MV SMI source (high) (register 5Dh):
Bit    Description    (Table P0165)
 7    PMI #15 - GNR_ACCESS
 6    PMI #14 - KBD_ACCESS
 5    PMI #13 - DSK_ACCESS
 4    PMI #12 - LCD_ACCESS
 3    PMI #11 - GNR_TIMER
 2    PMI #10 - KBD_TIMER
 1    PMI #9 - DSK_TIMER
 0    PMI #8 - LCD_TIMER
SeeAlso: #P0135,#P0164

Bitfields for OPTi 82C463MV clock stretching control (register 5Eh):
Bit    Description    (Table P0166)
 7    enable CPU clock stretch memory code cycle
 6    enable CPU clock stretch write cycle
 5    enable CPU clock stretch read cycle
 4    enable CPU clock stretch I/O cycle
 3    enable CPU clock stretch memory data cycle
 2    enable stop ATCLK when not in AT bus cycle
 1    ATCLK stretch
    =1 synchronous
    =0 asynchronous
 0    reserved (0)
SeeAlso: #P0135

Bitfields for OPTi 82C463MV resume interrupt control (register 5Fh):
Bit(s)    Description    (Table P0167)
 7    LCD_ACCESS includes AT bus video access
 6    LCD_ACCESS includes Local bus video access
 5    enable all resume sources of register 6Ah (see also #P0176,#P0159)
 4    RI counter count out will generate resume
 3-0    number of RI counts
SeeAlso: #P0135

Bitfields for OPTi 82C463MV debounce control (register 61h):
Bit(s)    Description    (Table P0168)
 7-6    LOWBAT and LLOWBAT pin debounce rate select
    if register 40h bit 6 =1
        00 no debounce
        01 250 microseconds
        10 8ms
        11 500ms
    if register 40h bit 6 =0
        00 no debounce
        01 62.5 microseconds
        10 2 ms
        11 125 ms
 5-4    SUSP/RSM pin debounce rate select
    if register 40h bit 6 =1
        00 reserved
        01 latch high to low edge
        10 4 ms (low to high)
        11 8 ms (low to high)
    if register 40h bit 6 =0
        00 reserved
        01 latch high to low edge
        10 1 ms (low to high)
        11 2 ms (low to high)
 3    reserved (0)
 2    enable STPCLK protocol for switching CPU clock frequencies
 1-0    STPCLK# delay (for use when STPCLK protocol is enabled)
    00 no delay
    01 120 microseconds
    10 240 microseconds
    11 1ms, if register 40h bit 6 set; 240 microseconds if clear
SeeAlso: #P0135,#P0146

Bitfields for OPTi 82C463MV doze-mode IRQ selects (register 62h):
Bit    Description    (Table P0169)
 7    enable IRQ13
 6    enable IRQ8
 5    enable IRQ7
 4    enable IRQ12
 3    enable IRQ5
 2    enable IRQ4
 1    enable IRQ3
 0    enable IRQ0
Notes:    in hardware doze-mode the selected interrupts will be used to re-load
      the hardware DOZE_TIMER and/or trigger the system out of doze-mode
    in APM doze-mode the selected interrupts will be used to trigger the
      system out of doze-mode only
SeeAlso: #P0135,#P0172,#P0170

Bitfields for OPTi 82C463MV idle timer IRQ selects (register 63h):
Bit    Description    (Table P0170)
 7    enable EPMI1 (level trigger)
 6    enable IRQ13
 5    enable IRQ8
 4    enable IRQ7
 3    enable IRQ5
 2    enable IRQ4
 1    enable IRQ3
 0    enable IRQ0
SeeAlso: #P0135,#P0169,#P0171

Bitfields for OPTi 82C463MV PMI#6 IRQ selects (register 64h):
Bit    Description    (Table P0171)
 7    enable IRQ14
 6    enable IRQ8
 5    enable IRQ7
 4    enable IRQ6
 3    enable IRQ5
 2    enable IRQ4
 1    enable IRQ3
 0    enable IRQ1
Note:    the value written into this register selects which IRQs generate
      PMI#6 in normal mode, the value read from this register indicates
      active IRQs at the time of the read
SeeAlso: #P0135,#P0159,#P0170

Bitfields for OPTi 82C463MV doze-mode configuration (register 65h):
Bit    Description    (Table P0172)
 7    enable monitoring all interrupt signals during hw or sw doze-mode
 6    doze-mode STPCLK protocol selector (see also #P0168)
    =1 STPCLK will latch for stopping the CPU clock (APM)
         The delay is determined by register 61h bits 1-0
    =0 STPCLK will pulse for changing the frequency of the CPU clock
      (hw doze-mode).
         The pulse width is determined by register 61h bits 1-0
 5    enable EPMI1 to reload hardware DOZE_TIMER and exit from hardware or
      software doze-mode
 4    enable recognition of SMI during APM stop clock
 3    allow IRQ1 to exit from hw or sw doze-mode (write-only)
    (see also #P0169)
 2-0    reserved (0)
SeeAlso: #P0135,#P0173

Bitfields for OPTi 82C463MV suspend control (register 66h):
Bit    Description    (Table P0173)
 7    refresh type during suspend
    =1 self refresh
    =0 normal refresh (refresh rate selected by register 67h bit 6)
 6    KBCLK during suspend
    =1 16 KHz
    =0 7.16 MHz (14.318 MHz /2)
 5    software (APM) CPU stop-clock control
    =1 the CPU clock can be stopped by entering APM doze-mode (that is
      setting register 50h bit 3 to 1)
    =0 APM doze-mode will use the hw doze-mode clock selected by
      bits 4-2 of register 41h
 4    avoid asserting HOLD before stopping the clock
 3    PIO3/STPGNT# pin selector
    =1 STPGNT# function (set register 57h bit 3 to input mode)
        This is for use with CPUs that use the hw stop grant signal
          to acknowledge stop request
    =0 PIO3 function (set register 57h bit 3 to determine input or
      output mode)
 2    PIO2/CPUSPD pin selector
    =1 CPUSPD function, CPU speed indicator output (set register 57h
      bit 2 to output mode)
    =0 PIO2 function (set register 57h bit 2 to determine input or
      output mode)
 1    PIO1/NOWS# pin selector
    =1 NOWS# function (set register 57h bit 1 to input mode)
    =0 PIO1 function (set register 57h bit 1 to determine input or
      output mode)
 0    enable CPU clock change request protocol
Note:    for hardware doze mode, bit 5 must be 0
SeeAlso: #P0135,#P0147,#P0154,#P0159,#P0174

Bitfields for OPTi 82C463MV CPU frequency (register 67h):
Bit(s)    Description    (Table P0174)
 7    CPU clock control during suspend
    =1 dynamic CPU (in suspend-mode, bits 2-0 select the CPU clock)
    =0 static CPU (in suspend-mode, 82C463MV stops the CPU clock)
 6    refresh control
    =1 slow refresh (128 ms)
    =0 normal refresh (15 ms for normal operation, 30 ms for suspend mode)
 5    PMU global enabler
 4    reserved (1)
 3    reserved (0)
 2-0    CPU clock frequency
    000 CPUCLK/1
    001 CPUCLK/2
    010 CPUCLK/4
    101 CPUCLK/3
    else reserved
SeeAlso: #P0135

Bitfields for OPTi 82C463MV timer clock source (register 68h):
Bit(s)    Description    (Table P0175)
 7-6    R_TIMER clock source selector
    00 SQW0
    01 SQW1
    10 SQW2
    11 SQW3
 5-4    IDLE_TIMER clock source selector (see bits 7-6)
 3-2    resume recovery time
    if register 40h bit 6 =1
        00 8 ms
        01 32 ms
        10 128 ms
        11 256 ms
    if register 40h bit 6 =0
        00 2 ms
        01 8 ms
        10 32 ms
        11 64 ms
 1    enable PPWR bit 1 suspend auto toggle (see also #P0156)
 0    enable PPWR bit 0 suspend auto toggle (see also #P0156)
Note:    bits 1 and 0 are not influenced by mask bits 5 and 4 of register 54h
SeeAlso: #P0135,#P0146

Bitfields for OPTi 82C463MV resume IRQ selects (register 6Ah):
Bit    Description    (Table P0176)
 7    enable EPMI2 (resume on a rising edge)
 6    enable EPMI1 (resume on a rising edge)
 5    enable IRQ8 (resume on a falling edge)
 4    enable IRQ7 (resume on a rising edge)
 3    enable IRQ5 (resume on a rising edge)
 2    enable IRQ4 (resume on a rising edge)
 1    enable IRQ3 (resume on a rising edge)
 0    enable IRQ1 (resume on a rising edge)
SeeAlso: #P0135

Bitfields for OPTi 82C463MV resume sources (register 6Bh):
Bit(s)    Description    (Table P0177)
 7    refresh pulse width during sequencer operation
    =1 6 AT clocks
    =0 4 AT clocks
 6-3    reserved (0)
 2-0    resume sources (read-only)
    001 RI
    010 INTR (as selected in register 6Ah)
    100 SUSP/RSM pin
    else reserved
SeeAlso: #P0135,#P0176
----------P00220024--------------------------
PORT 0022-0024 - OPTi 82C493 System Controller (SYSC) - CONFIGURATION REGISTERS
Desc:    The OPTi 486SXWB contains three chips and is designed for systems
      running at 20, 25 and 33MHz.    The chipset includes an 82C493 System
      Controller (SYSC), the 82C392 Data Buffer Controller, and the
      82C206 Integrated peripheral Controller (IPC).
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  configuration register index (see #P0178)
0024  RW  configuration register data

(Table P0178)
Values for OPTi 82C493 System Controller configuration register index:
 20h    Control Register 1 (see #P0179)
 21h    Control Register 2 (see #P0180)
 22h    Shadow RAM Control Register 1 (see #P0181)
 23h    Shadow RAM Control Register 2 (see #P0182)
 24h    DRAM Control Register 1 (see #P0183)
 25h    DRAM Control Register 2 (see #P0184)
 26h    Shadow RAM Control Register 3 (see #P0185)
 27h    Control Register 3 (see #P0186)
 28h    Non-cachable Block 1 Register 1 (see #P0187)
 29h    Non-cachable Block 1 Register 2 (see #P0188)
 2Ah    Non-cachable Block 2 Register 1 (see #P0187)
 2Bh    Non-cachable Block 2 Register 2 (see #P0188)

Bitfields for OPTi-82C493 Control Register 1:
Bit(s)    Description    (Table P0179)
 7-6    Revision of 82C493 (readonly) (default=01)
 5    Burst wait state control
    1 = Secondary cache read hit cycle is 3-2-2-2 or 2-2-2-2
    0 = Secondary cache read hit cycle is 3-1-1-1 or 2-1-1-1 (default)
    (if bit 5 is set to 1, bit 4 must be set to 0)
 4    Cache memory data buffer output enable control
    0 = disable (default)
    1 = enable
    (must be disabled for frequency <= 33Mhz)
 3    Single Address Latch Enable (ALE)
    0 = disable (default)
    1 = enable
    (if enabled, SYSC will activate single ALE rather than multiples
      during bus conversion cycles)
 2    enable Extra AT Cycle Wait State (default is 0 = disabled)
 1    Emulation keyboard Reset Control
    0 = disable (default)
    1 = enable
    Note:    This bit must be enabled in BIOS default value; enabling this
          bit requires HALT instruction to be executed before SYSC
          generates processor reset (CPURST)
 0    enable Alternative Fast Reset (default is 0 = disabled)
SeeAlso: #P0180,#P0186

Bitfields for OPTi-82C493 Control Register 2:
Bit(s)    Description    (Table P0180)
 7    Master Mode Byte Swap Enable
    0 = disable (default)
    1 = enable
 6    Emulation Keyboard Reset Delay Control
    0 = Generate reset pulse 2us later (default)
    1 = Generate reset pulse immediately
 5    disable Parity Check (default is 0 = enabled)
 4    Cache Enable
    0 = Cache disabled and DRAM burst mode enabled (default)
    1 = Cache enabled and DRAM burst mode disabled
 3-2    Cache Size
    00  64KB (default)
    01  128KB
    10  256KB
    11  512KB
 1    Secondary Cache Read Burst Cycles Control
    0 = 3-1-1-1 cycle (default)
    1 = 2-1-1-1 cycle
 0    Cache Write Wait State Control
    0 = 1 wait state (default)
    1 = 0 wait state
SeeAlso: #P0179,#P0186

Bitfields for OPTi-82C493 Shadow RAM Control Register 1:
Bit(s)    Description    (Table P0181)
 7    ROM(F0000h - FFFFFh) Enable
    0 = read/write on write-protected DRAM
    1 = read from ROM, write to DRAM (default)
 6    Shadow RAM at D0000h - EFFFFh Area
    0 = disable (default)
    1 = enable
 5    Shadow RAM at E0000h - EFFFFh Area
    0 = disable shadow RAM (default)
        E0000h - EFFFFh ROM is defaulted to reside on XD bus
    1 = enable shadow RAM
 4    enable write-protect for Shadow RAM at D0000h - DFFFFh Area
    0 = disable (default)
    1 = enable
 3    enable write-protect for Shadow RAM at E0000h - EFFFFh Area
    0 = disable (default)
    1 = enable
 2    Hidden refresh enable (with holding CPU)
    (Hidden refresh must be disabled if 4Mx1 or 1M x4 bit DRAM are used)
    1 = disable (default)
    0 = enable
 1    unused
 0    enable Slow Refresh (four times slower than normal refresh)
    (default is 0 = disable)
SeeAlso: #P0182

Bitfields for OPTi-82C493 Shadow RAM Control Register 2:
Bit(s)    Description    (Table P0182)
 7    enable Shadow RAM at EC000h - EFFFFh area
 6    enable Shadow RAM at E8000h - EBFFFh area
 5    enable Shadow RAM at E4000h - E7FFFh area
 4    enable Shadow RAM at E0000h - E3FFFh area
 3    enable Shadow RAM at DC000h - DFFFFh area
 2    enable Shadow RAM at D8000h - DBFFFh area
 1    enable Shadow RAM at D4000h - D7FFFh area
 0    enable Shadow RAM at D0000h - D3FFFh area
Note:    the default is disabled (0) for all areas

Bitfields for OPTi-82C493 DRAM Control Register 1:
Bit(s)    Description    (Table P0183)
 7    DRAM size
    0 = 256K DRAM mode
    1 = 1M and 4M DRAM mode
 6-4    DRAM types used for bank0 and bank1
    bits 7-4  Bank0      Bank1
    0000      256K         x
    0001      256K      256K
    0010      256K        1M
    0011         x         x
    01xx         x         x
    1000        1M         x    (default)
    1001        1M        1M
    1010        1M        4M
    1011        4M        1M
    1100        4M         x
    1101        4M        4M
    111x         x         x
 3    unused
 2-0    DRAM types used for bank2 and bank3
    bits 7,2-0  Bank2  Bank3
    x000       1M        x
    x001       1M       1M
    x010        x        x
    x011       4M       1M
    x100       4M        x
    x101       4M       4M
    x11x        x        x  (default)
SeeAlso: #P0184

Bitfields for OPTi-82C493 DRAM Control Register 2:
Bit(s)    Description    (Table P0184)
 7-6    Read cycle additional wait states
    00 not used
    01 = 0
    10 = 1
    11 = 2 (default)
 5-4    Write cycle additional wait states
    00 = 0
    01 = 1
    10 = 2
    11 = 3 (default)
 3    Fast decode enable
    0 = disable fast decode. DRAM base wait states not changed (default)
    1 = enable fast decode. DRAM base wait state is decreased by 1
    Note:    This function may be enabled in 20/25Mhz operation to speed up
          DRAM access.    If bit 4 of index register 21h (cache enable
          bit) is enabled, this bit is automatically disabled--even if
          set to 1
 2    unused
 1-0    ATCLK selection
    00  ATCLK = CLKI/6 (default)
    01  ATCLK = CLKI/4 (default)
    10  ATCLK = CLKI/3
    11  ATCLK = CLK2I/5  (CLKI * 2 /5)
    Note:    bit 0 will reflect the BCLKS (pin 142) status and bit 1 will be
          set to 0 when 82C493 is reset.
SeeAlso: #P0183,#P0185

Bitfields for OPTi-82C493 Shadow RAM Control Register 3:
Bit(s)    Description    (Table P0185)
 7    unused
 6    Shadow RAM copy enable for address C0000h - CFFFFh
    0 = Read/write at AT bus (default)
    1 = Read from AT bus and write into shadow RAM
 5    Shadow write protect at address C0000h - CFFFFh
    0 = Write protect disable (default)
    1 = Write protect enable
 4    enable Shadow RAM at C0000h - CFFFFh
 3    enable Shadow RAM at CC000h - CFFFFh
 2    enable Shadow RAM at C8000h - CBFFFh
 1    enable Shadow RAM at C4000h - C7FFFh
 0    enable Shadow RAM at C0000h - C3FFFh
Note:    the default is disabled (0) for bits 4-0
SeeAlso: #P0183,#P0184

Bitfields for OPTi-82C493 Control Register 3:
Bit(s)    Description    (Table P0186)
 7    enable NCA# pin to low state (default is 1 = enabled)
 6-5    unused
 4    Video BIOS at C0000h - C8000h non-cacheable
    0 = cacheable
    1 = non-cacheable (default)
 3-0    Cacheable address range for local memory
    0000  0 - 64MB
    0001  0 - 4MB (default)
    0010  0 - 8MB
    0011  0 - 12MB
    0100  0 - 16MB
    0101  0 - 20MB
    0110  0 - 24MB
    0111  0 - 28MB
    1000  0 - 32MB
    1001  0 - 36MB
    1010  0 - 40MB
    1011  0 - 44MB
    1100  0 - 48MB
    1101  0 - 52MB
    1110  0 - 56MB
    1111  0 - 60MB
    Note:    If total memory is 1MB or 2MB the cacheable range is 0-1 MB or
          0-2 MB and independent of the value of bits 3-0
SeeAlso: #P0179,#P0180

Bitfields for OPTi-82C493 Non-cacheable Block Register 1:
Bit(s)    Description    (Table P0187)
 7-5    Size of non-cachable memory block
    000  64K
    001  128K
    010  256K
    011  512K
    1xx  disabled (default)
 4-2    unused
 1-0    Address bits 25 and 24 of non-cachable memory block (default = 00)
Note:    this register is used together with configuration register 29h
      (non-cacheable block 1) or register 2Bh (block 2) (see #P0188) to
      define a non-cacheable block.     The starting address must be a
      multiple of the block size
SeeAlso: #P0178,#P0188

Bitfields for OPTi-82C493 Non-cacheable Block Register 2:
Bit(s)    Description    (Table P0188)
 7-0    Address bits 23-16 of non-cachable memory block (default = 0001xxxx)
Note:    the block address is forced to be a multiple of the block size by
      ignoring the appropriate number of the least-significant bits
SeeAlso: #P0178,#P0187
----------P00220024--------------------------
PORT 0022-0024 - OPTi "Viper" (82C557) CHIPSET - SYSTEM CONTROL REGISTERS
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0189)
0023  RW  DMA clock select (see #P0087)
0024  RW  chip set data

(Table P0189)
Values for OPTi "Viper" (82C557) system control registers:
 00h    Byte Merge/Prefetch and Sony Cache Module Control register (see #P0190)
 00h    Compatible DRAM Configuration register 1 (see #P0191) (refer to note)
 01h    DRAM Control register 1 (see #P0192)
 02h    Cache Control register 1 (see #P0193)
 03h    Cache Control register 2 (see #P0194)
 04h    Shadow RAM Control register 1 (see #P0195)
 05h    Shadow RAM Control register 2 (see #P0197)
 06h    Shadow RAM Control register 3 (see #P0198)
 07h    Tag Test register (see #P0199)
 08h    CPU Cache Control register (see #P0200)
 09h    System Memory Function register (see #P0201)
 0Ah    DRAM Hole A Address Decode register 1 (see #P0202)
 0Bh    DRAM Hole B Address Decode register 2 (see #P0203)
 0Ch    Extended DMA register (see #P0204)
 0Dh    Clock Control register (see #P0205)
 0Eh    Cycle Control register 1 (see #P0206)
 0Fh    Cycle Control register 2 (see #P0207)
 10h    Miscellaneous Control register 1 (see #P0208)
 11h    Miscellaneous Control register 2 (see #P0209)
 12h    Refresh Control register (see #P0210)
 13h    Memory Decode Control register 1 (see #P0211)
 14h    Memory Decode Control register 2 (see #P0213)
 15h    PCI Cycle Control register 1 (see #P0214)
 16h    Dirty/Tag RAM Control register (see #P0215)
 17h    PCI Cycle Control register 2 (see #P0216)
 18h    Tristate Control register (see #P0217)
 19h    Memory Decode Control register 3 (see #P0218)
 1Ah-1Fh reserved
Note:    Byte Merge/Prefetch and Sony Cache Module Control register is accessed
      through register 00h when bit 7 of register 13h is set, otherwise
      Compatible DRAM Configuration register 1 is accessed as register 00h
    reserved registers 1Ah-1Fh must be written to 0
SeeAlso: #P0121,#P0211

Bitfields for OPTi "Viper" Byte Merge / Sony Cache Module Control register:
Bit(s)    Description    (Table P0190)
 7    enable pipelining of single CPU cycles to memory
 6    enable video memory byte/word read prefetch. Enables the prefetching
      of bytes/words from PCI video memory to the CPU
 5    enable Sony SONIC-2WP support. If set, the ensure that the L2 cache
      has been disabled (register 02h bits 3-2)
 4    enable byte/word merge support
 3    enable byte/word merging with CPU pipelining (NA# generation) support
 2-1    time-out counter for byte/word merge. Determines the maximum time
      difference between two consecutive PCI bye/word writes to allow
      merging
    00  4 CPU CLKs
    01  8 CPU CLKs
    10 12 CPU CLKs
    11 16 CPU CLKs
 0    enable internal hold requests to be blocked while performing byte merge
SeeAlso: #P0189

Bitfields for OPTi "Viper" Compatible DRAM Configuration register 1:
Bit(s)    Description    (Table P0191)
 7    enable pipelining of single CPU cycles to memory
 6    second bank SIMM selection. SIMMs need to be single sided
    0 single sided SIMM not installed in bank 0
    1 single sided SIMM installed in bank 0
 5    first bank SIMM selection. SIMMs need to be single sided
    0 single sided SIMM not installed in bank 0
    1 single sided SIMM installed in bank 0
 4-0    banks 0 thru 3 DRAM configuration
    (val)    Bank0    Bank1    Bank2    Bank3
    00000    256K    256KB    -    -
    00001    512K    512K    -    -
    00010    1M    1M    -    -
    00011    2M    2M    -    -
    00100    4M    4M    -    -
    00101    8M    8M    -    -
    00110    256K    256K    256K    256K
    00111    256K    256K    512K    512K
    01000    512K    512K    512K    512K
    01001    256K    256K    1M    1M
    01010    512K    512K    1M    1M
    01011    1M    1M    1M    1M
    01100    256K    256K    2M    2M
    01101    512K    512K    2M    2M
    01110    1M    1M    2M    2M
    01111    2M    2M    2M    2M
    10000    256K    256K    4M    4M
    10001    512K    512K    4M    4M
    10010    1M    1M    4M    4M
    10011    2M    2M    4M    4M
    10100    4M    4M    4M    4M
    10101    256K    256K    8M    8M
    10110    512K    512K    8M    8M
    10111    1M    1M    8M    8M
    11000    2M    2M    8M    8M
    11001    4M    4M    8M    8M
    11010    8M    8M    8M    8M
Note:    these settings maintain backward compatibility with the "Python"
      (82C546/82C547) chipset, and they do not allow for much flexibility
SeeAlso: #P0189

Bitfields for OPTi "Viper" (82C557) DRAM Control register 1:
Bit(s)    Description    (Table P0192)
 7    row address hold after RAS# active in CLKs
    0 2 CLKs
    1 1 CLK
 6    RAS# active/inactive on entering master mode
    0 normal page mode when starting a master cycle, RAS# will remain
    1 RAS# inactive when starting a master cycle
 5-4    RAS pulse width used during refresh
    00 7 CLKs
    01 6 CLKs
    10 5 CLKs
    11 4 CLKs
 3    CAS pulse width during reads
    0 3 CLKs
    1 2 CLKs
 2    CAS pulse width during writes
    0 3 CLKs
    1 2 CLKs
 1-0    RAS precharge time
    00 6 CLKs
    01 5 CLKs
    10 4 CLKs
    11 3 CLKs
SeeAlso: #P0189,#P0193,#P0219

Bitfields for OPTi "Viper" (82C557) Cache Control register 1:
Bit(s)    Description    (Table P0193)
 7-6    cache size selection; determines size of the L2 cache, along with
      register 0Fh bit 0. When set, it works as a *16 multiplier
    00 (Viper)  64K (1M when register 0Fh bit 0 set)
       (Vendetta) reserved
    01 (Viper) 128K (2M when register 0Fh bit 0 set)
       (Vendetta) reserved
    10 256K (reserved when register 0Fh bit 0 set)
    11 512K (reserved when register 0Fh bit 0 set)
 5-4    cache write policy; determines the write policy for the L2 cache
    00 L2 cache write-through
    01 Adaptive Write-back Mode 1
    10 Adaptive Write-back Mode 2
    11 L2 cache write-back
 3-2    cache mode select; determines the operating mode of the L2 cache
    00 disable
    01 Test Mode 1, External Tag Write (Tag data write-through reg. 07h)
    10 Test Mode 2, External Tag Read (Tag data read from register 07h)
    11 enable L2 cache
 1    enable DRAM posted write
 0    CAS precharge time
    0 2 CLKs
    1 1 CLK
SeeAlso: #P0189,#P0199,#P0207,#P0194,#P0219

Bitfields for OPTi "Viper" (82C557) Cache Control register 2:
Bit(s)    Description    (Table P0194)
 7-6    L2 cache write burst mode timings
    00 X-4-4-4
    01 X-3-3-3
    10 X-2-2-2
    11 X-1-1-1
 5-4    L2 cache write lead-off cycle timings
    00 5-X-X-X
    01 4-X-X-X
    10 3-X-X-X
    11 2-X-X-X
 3-2    L2 cache read burst mode timings
    00 X-4-4-4
    01 X-3-3-3
    10 X-2-2-2
    11 X-1-1-1
 1-0    L2 cache read lead-off cycle timings
    00 5-X-X-X
    01 4-X-X-X
    10 3-X-X-X
    11 2-X-X-X
Note:    SRAM double bank implementation does not support lead-off timing
SeeAlso: #P0189,#P0193,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Shadow RAM Control register 1:
Bit(s)    Description    (Table P0195)
 7-6    CC000-CFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 5-4    C8000-CBFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 3    enable synchronous SRAM pipelined read cycle 1-1-1-1
 2    E0000-EFFFF range selection
    0 area will always be non-cacheable
    1 are will be treated like the F0000h BIOS area
 1-0    C0000-C7FFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
Note:    bit 3 will act only when register 11h bit 3 and register 03h bits 3-2
      are all set
    when bit 2 is set, register 06h bits 3-0 should be set identically
SeeAlso: #P0189,#P0197,#P0219

(Table P0196)
Values for OPTi "Viper"/"Vendetta" Shadow RAM Control setting:
 00    read/write PCI bus
 01    read from DRAM/write to PCI
 10    read from PCI/write to DRAM
 11    read from/write to DRAM
SeeAlso: #P0195,#P0197,#P0198,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Shadow RAM Control register 2:
Bit(s)    Description    (Table P0197)
 7-6    DC000-DFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 5-4    D8000-DBFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 3-2    D4000-D7FFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 1-0    D0000-D3FFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
SeeAlso: #P0189,#P0195,#P0198,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Shadow RAM Control register 3:
Bit(s)    Description    (Table P0198)
 7    DRAM hole in system memory from 80000-9FFFF; gives the user the option
      to have some other device in this address range instead of system
      memory. When set, the SYSC will not start the system DRAM controller
      for accesses to this particular address range
    0 no memory hole
    1 enable memory hole
 6    wait state addition for PCI master snooping
    0 do not add a wait state
    1 add a wait state for the cycle access to finish and then do snooping
 5    enable C0000-C7FFF cacheability in L1 and L2 cache memory
 4    enable F0000-FFFFF cacheability in L1 and L2 cache memory
 3-2    F0000-FFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
 1-0    E0000-EFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM (see #P0196)
Note:    L1 cacheability can be disabled thru register 08h bit 0
    If register 04h bit 2 is set, then F0000-FFFFF and E0000-EFFFF R/W
    control settings should have similar values
SeeAlso: #P0189,#P0197,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Tag Test register:
Bit(s)    Description    (Table P0199)
 7-0    Tag Test register; when in cache Test Mode, data is read from/written
      to this register
SeeAlso: #P0189,#P0193,#P0219

Bitfields for OPTi "Viper"/"Vendetta" CPU Cache Control register:
Bit(s)    Description    (Table P0200)
 7    L2 cache single/double bank select
    0 (Viper) two banks of L2 cache
      (Vendetta) reserved
    1 single bank of L2 cache (non-interleaved)
 6    enable snoop filtering for bus masters
 5    CPU HITM# pin sample timing
    0 (Viper) delay one clock, therefore HITM# sampled on the third rising
        edge of LCLK after EADS# has been asserted
      (Vendetta) reserved
    1 do not delay, therefore HITM# sampled on the second rising edge
 4    enable parity checking
 3    Tag/Dirty RAM implementation
    0 (Viper) Tag and Dirty are on separate chips
      (Vendetta) reserved
    1 Tag and Dirty are on the same chip
 2    enable CPU address pipelining
 1    enable L1 cache write-back and write-through control
    0 write-through only
    1 write-back enabled
 0    disable BIOS and Video BIOS areas cacheability in L1 cache
Notes:    If asynchronous SRAM, then cache memory banks (when two are present)
      are interleaved, otherwise, they are not
    When register 04h bit 2 is set, bit 0 affects BIOS area
      E0000-EFFFF; when clear, bit 0 affects area F0000-FFFFF
SeeAlso: #P0189,#P0201,#P0219

Bitfields for OPTi "Viper" (82C557) System Memory Function register:
Bit(s)    Description    (Table P0201)
 7-6    DRAM Hole B size
    (address specified by register 0Bh, and register 0Ch bits 3-2)
    00 512K
    01   1M
    10   2M
    11   4M
 5-4    DRAM Hole B control mode
    00 disable
    01 write-through for L1 and L2 cache
    10 non-cacheable for L1 and L2 cache
    11 enable hole in DRAM
 3-2    DRAM Hole A size (settings same as bits 7-6)
    (address specified by register 0Ah, and register 0Ch bits 1-0)
 1-0    DRAM Hole A control mode (settings same as bits 5-4)
SeeAlso: #P0189,#P0203,#P0204,#P0219

Bitfields for OPTi "Viper" (82C557) DRAM Hole A Address Decode register 1:
Bit(s)    Description    (Table P0202)
 7-0    DRAM Hole A address, bits 26-19
    (bits 1-0 of register 0Ch map onto bits 28-27 of HA lines)
SeeAlso: #P0189,#P0204,#P0203,#P0219

Bitfields for OPTi "Viper" (82C557) DRAM Hole B Address Decode register 2:
Bit(s)    Description    (Table P0203)
 7-0    DRAM Hole B address, bits 26-19
    (bits 3-2 of register 0Ch map onto bits 28-27 of HA lines)
SeeAlso: #P0189,#P0204,#P0202,#P0219

Bitfields for OPTi "Viper" (82C557) Extended DMA register:
Bit(s)    Description    (Table P0204)
 7    reserved (0)
 6    Fast BRDY# generation for DRAM write page hits
    0 BRDY# for DRAM writes generated on the fourth clock
    1 BRDY# for DRAM writes generated on the third clock
 5    (Viper) HACALE one-half a clock cycle earlier
        0 HACALE normal timing
        1 HACALE one-half a clock cycle early enabled
    (Vendetta) reserved
 4    (Viper) wider cache WE# pulse
        0 cache WE# pulse width is normal (~15ns)
        1 cache WE# pulse is wider (~17.5ns)
    (Vendetta) reserved
 3-2    DRAM Hole B starting address, bits 28-27 (see also #P0202)
 1-0    DRAM Hole A starting address, bits 28-27 (see also #P0203)
Note:    bits 26-19 of memory holes A and B are mapped from Indices 0Ah and 0Bh
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Clock Control register:
Bit(s)    Description    (Table P0205)
 7    (Viper) clock source for generation the syncronous SRAM timing
        0 CPU clock is the source for the timing and control signals
        1 ECLK is the source for the timing and control signals
    (Vendetta) reserved (1)
 6    (Viper) this bit is set if the skew between ECLK and CPU clock is too
      large (read-only bit, set by the 82C557 chip)
    (Vendetta) reserved (read-only)
 5    (Viper) enable auto skew detect; when this bit is set, bit 4 will be
      set automatically if the skew between CLK and ECLK is too large
    (Vendetta) BRDY# PCI-to-ISA bridge request remove BOFF# disable
 4    (Viper) ECLK - CLK skew, activated when synchronou SRAMs are being used
        0 skew between CLK and ECLK is not too large
        1 skew is too large
    (Vendetta)
        0 preemption when CPU needs memory
        1 reserved
 3    enable A0000-BFFFF as system memory
 2    wait state addition for PCI master doing address toggling as a 486
    0 linear burst mode style address toggling - no wait state addition
    1 i486 burst style address toggling - one wait state needs to be added
 1    (Viper) PCI cycle claimed by the 82C557 during PCI pre-snoop cycle
        0 82C557 does not claim the PCI cycle after it asserts STOP#
        1 82C557 claims the PCI cycle after it asserts STOP#
    (Vendetta) reserved
 0    slow CPU clock; should be set if the CPU clock frequency has been
      reduced
        0 CPU clock frequency is normal
        1 CPU clock has been slowed down
    (Vendetta) reserved
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Cycle Control register 1:
Bit(s)    Description    (Table P0206)
 7-6    (Viper) PCI master read burst wait state control
        00 4 cycles
        01 3 cycles
        10 2 cycles
        11 reserved
    (Vendetta) reserved
 5-4    (Viper) PCI master write burst wait state control (same settings as
      bits 7-6)
    (Vendetta) reserved
 3    master cycle parity enable; this bit becomes applicable when bit 4 of
      register 08h is set
    0 enable parity check during master cycles
    1 disable parity check during master cycles
 2    (Viper) HACALE timing control
        0 HACALE high during HITM# before CPU ADS#
        1 HACALE low and CA4 always enabled during HITM cycle
    (Vendetta) fast NA# generation enable
 1    enable write protection for L1 BIOS
 0    PCI line comparator; this bit is only valid when bit 6 of register 08h
      is set
    0 use line comparator in PCI master
    1 generate inquire cycle for every new FRAME#
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Cycle Control register 2:
Bit(s)    Description    (Table P0207)
 7    enable PCI pre-snooping feature
 6    (Viper) AT master wait state control
        0 do not add any wait states for AT master cycles
        1 add wait wait states for AT master cycles
    (Vendetta) ISA master access wait states enable (use if PCICLK <33MHz)
 5    (Viper) wait state addition for synchronous SRAM even byte access
        0 do not add a wait state for a synchronous SRAM even byte access
        1 add one wait state for a synchronous SRAM even byte access
    (Vendetta) L2 write-through mode CPU-to-DRAM deep buffer enable
 4    PCI wait state addition for synchronous SRAM L2 cache implementation
    0 master does not wait for end of current cycle + CPU-PCI clock to
      become synchronous
    1 master waits for end of current cycle + wait for CPU-PCI clock to
      become synchronous
 3    (Viper) reserved
    (Vendetta) L2 single cycle write hit when line already dirty
        0 = 5 CLKs
        1 = 3 CLKs
 2    (Viper) ADSC# generation for synchronous SRAM read cycle
        0 generate ADSC# immediately after CPU ADS# goes active
        1 generate ADSC# one clock after CPU ADS# goes active
    (Vendetta) CPU to L2 cache hit cycle chipset ADSC# generation disable
 1    (Viper) reserved
    (Vendetta) two-PCI master fix
        0 revision 2.0
 0    L2 cache size selector; works along with bits 1-0 of register 02h
    0 below 1M
    1 1M and above (Viper only)
SeeAlso: #P0189,#P0193,#P0219

Bitfields for OPTi "Viper" (82C557) Miscellaneous Control register 1:
Bit(s)    Description    (Table P0208)
 7    (Viper) early decode of PCI/VL/AT cycle
    (Vendetta) early decode of PCI/ISA cycle
    0 CPU to <bus> slave cycle triggered after second T2
    1 CPU to <bus> slave cycle triggered after first T2
 6    (Viper) cache modified write cycle timing
        0 use the old address changing method, as in the 82C546/82C547
        1 two bank cache, CA4 delayed one-half a clock for write cycles
    (Vendetta) reserved
 5    pipelined read cycle timing; determines the lead-off cycle
    0 3-X-X-X read followed by a 3-X-X-X piped read cycle
    1 3-X-X-X read followed by a 2-X-X-X piped read cycle
 4    (Viper) enable write hit pipelined
        0 do not enable 2-X-X-X pipelined write hit cycles
        1 enable 2-X-X-X pipelined write hit cycles
    (Vendetta) reserved
 3    (Viper) write pulse timing control for cache write hit cycles
        0 do not change the write pulse timing during X-2-2-2 write hit
          cycles
        1 move the write pulse one-half a clock later in X-2-2-2 write hit
          cycles
    (Vendetta) reserved
 2    (Viper) write pulse timing control for cache write hit cycles
        0 do not change the write pulse timing during 3-X-X-X write hit
          cycles
        1 move the write pulse one-half a clock later in 3-X-X-X write hit
          cycles
    (Vendetta) reserved
 1    (Viper) external 74F126 select
        0 an external 74F126 is installed for CA3 and CA4
        1 an external 74F126 is not installed for CA3 and CA4
    (Vendetta) reserved (1)
 0    LCLK select control; when this bit is set, the timing constraints
      between the LCLK and the CPUCLK inputs to the SYSC need to be met.
      This constraints are: LCLK <= 1/2 CPUCLK period before CPUCLK, and
      LCLK <= 0.5ns after CPUCLK
    0 LCLK is asynchronous to the CPUCLK
    1 LCLK is synchronous to the CPUCLK; LCLK = CPUCLK/2
Note:    bit 1 should always be set to 1
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Miscellaneous Control register 2:
Bit(s)    Description    (Table P0209)
 7-6    reserved; must be set to 0
 5    cache inactive during Idle state control
    0 SRAM always active
    1 SRAM inactive during Idle state (Viper only)
 4    next address (NA#) mode control
    0 normal NA# timing used with asynchronous SRAMs
    1 new NA# timing for synchronous SRAMs; used only when CPU operating
      at 50MHz
 3    SRAM type
    0 asynchronous SRAM (Viper only)
    1 synchronous SRAM
 2    (Viper) enable page miss posted write
    (Vendetta) reserved
 1    (Viper) ISA/DMA IOCHRDY control
        0 old mode, no IOCHRDY during line hit
        1 drive IOCHRDY low until cycle is finished
    (Vendetta) reserved
 0    (Viper) delay start
        0 old mode, do not delay internal master cycle after an inquire
          cycle
        1 delay internal master cycles by one LCLK after an inquire cycle
    (Vendetta) reserved
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Refresh Control register:
Bit(s)    Description    (Table P0210)
 7    REFRESH#/32KHz source selection
    0 REFRESH# source is REFRESH# pulse from the 82C558 or the ISA master
    1 REFRESH# pulse source is a 32KHz clock
 6    reserved; must be written to 0
 5-4    suspend mode refresh
    00 from CLK state machine
    01 slef refresh based on 32KHz only
    10 normal refresh based on 32KHz only
    11 undefined
 3-2    slow refresh
    00 refresh on every REFRESH#/32KHz falling edge
    01 refresh on alternate REFRESH#/32KHz falling edge
    10 refresh on one in four REFRESH#/32KHz falling edge
    1 refresh on every REFRESH#/32KHz toggle
 1    enable bits 23-17 of LA from Refresh Page register (8Fh) during refresh
 0    enable output of bits 7-4 of DBC MP during master write
    0 disable the DBC from generation the MP[7:4] lines during PCI master
      writes; there must be a pull-up on MP0
    1 enable the DBC to generate the MP[7:4] lines during PIC master
      writes; there must be a pull-down on MP0
SeeAlso: #P0189,#P0211

Bitfields for OPTi "Viper" (82C557) Memory Decode Control register 1:
Bit(s)    Description    (Table P0211)
 7    (Viper) memory decode select
    0 Byte Merge/Prefetch and Sony Cache Module Control register is
      available in register 00h; compatible to 82C547 DRAM configurations
    1 Compatible DRAM Configuration register is available in register 00h;
      full decode option; this gives the user maximum flexibility in
      choosing different DRAM configurations
    (Vendetta) reserved (1)
 6-4    full decode for logical bank 1 (RAS#1), if bit 7 set. This settings
      apply to 36-pin banks only (see #P0212)
 3    enable SMRAM
 2-0    full decode for logical bank 0 (RAS#0), if bit 7 set. This settings
      apply to 36-pin banks only (see #P0212)
SeeAlso: #P0189,#P0190,#P0191,#P0219

(Table P0212)
Values for OPTi "Viper" (82C557) Memory Bank Decode Control registers:
 000      0K
 001    256K
 010    512K
 011      1M
 100      2M
 101      4M
 110      8M
 111     16M
SeeAlso: #P0211,#P0213,#P0216

Bitfields for OPTi "Viper" (82C557) Memory Decode Control register 2:
Bit(s)    Description    (Table P0213)
 7    (Viper) reserved; must be written to 0
    (Vendetta) reserved (1)
 6-4    full decode for logical bank 3 (RAS#3), if register 13h bit 7 is set
      (see #P0212)
 3    SMRAM control
    0 disable SMRAM (enable SMRAM for both Code and Data if SMIACT# is
      active and register 13h bit 3 is set)
    1 enable SMRAM (enable SMRAM for Code only if SMIACT# is active and
      register 13h bit 3 is set)
 2-0    full decode for logical bank 2 (RAS#2), if register 13h bit 7 is set
      (see #P0212)
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) PCI Cycle Control register 1:
Bit(s)    Description    (Table P0214)
 7-6    CPU master to PCI memory slave, write IRDY# control
    00 3 LCLKs after end of address phase
    01 2 LCLKs after end of address phase
    10 1 LCLK after end of address phase
    11 0 LCLK after end of address phase
 5-4    CPU master to PCI slave write posting, bursting control
    00 PCI slave write, no posting, no bursting
    01 PCI slave write, posting enabled, no bursting
    10 PCI slave write, posting enabled, conservative bursting
    11 PCI slave write, posting enabled, aggressive bursting
 3-2    master retry timer
    00 retries unmasked after 10 PCICLKs
    01 retries unmasked after 18 PCICLKs
    10 retries unmasked after 34 PCICLKs
    11 retries unmasked after 66 PCICLKs
 1    reserved; must be written to 0
 0    PCI cycle, FRAME# timing control for pipelined cycles
    0 PCI cycle FRAME# assertion is done in the conservative mode style
    1 PCI cycle FRAME# assertion is done in the aggressive mode style
SeeAlso: #P0189,#P0216,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Dirty/Tag RAM Control register:
Bit(s)    Description    (Table P0215)
 7    (Viper) Dirty pin selection; reflects the kind of SRAM chosen to
      implement the Dirty RAM; it also determines the functionality of the
      DIRTYI pin of the 82C557
        0 DIRTYI pin is input-only
        1 DIRTYI pin is bidirectional
    (Vendetta) reserved (1)
 6    reserved; must be written to 0
 5    Tag RAM size
    0 = 8-bit Tag (Viper only)
    1 = 7-bit Tag
 4    write hit cycle lead-off time when combining Dirty/Tag RAM
    0 single write hit lead-off cycle = 5 cycles
    1 single write hit lead-off cycle = 4 cycles
 3    pre-snoop control
    0 pre-snoop for starting address 0 only
    1 pre-snoop for all addresses except those on the line boundary
 2    (Viper) reserved; must be written to 0
    (Vendetta) synchronization between LCLK and CLK
        0 LCLK is asynchronous to CLK
        1 LCLK is synchronous to CLK
 1    (Viper) CPU to VL read access, DBC DLE# bits 1-0 timing
        0 LCLK high
        1 LCLK low
    (Vendetta) reserved
 0    (Viper) HDOE# timing control
        0 HDOE# is negated normally
        1 HDOE# is negated one clock before the cycle finishes
    (Vendetta) reserved
Note:    (Vendetta) bit 4 should be set same as register 22h bit 0
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper"/"Vendetta" PCI Cycle Control register 2:
Bit(s)    Description    (Table P0216)
 7    (Vipder) NA# assertion control for PCI slave accesses when synchronous
      PCI clock is used
        0 no pipelining for accesses to PCI slave
        1 pipelining enabled for accesses to PCI slave for both synchronous
          and asynchronous PCI solutions; if set, overrides bit 6
    (Vendetta) MD drive strength
        0 =     8 mA
        1 = 12 mA
 6    NA# assertion control for PCI slave accesses when asynchronous PCI
      clock is used
    0 no pipelining for accesses to PCI slave
    1 pipelining enabled for accesses to PCI slave for an asynchronous PCI
      implementation; this bit is overridden if bit 7 is set
 5    (Viper) enable support for Intel standard BSRAM
        0 no support for Intel standard BSRAM
        1 support for Intel standard BSRAM; should be set only if using two
          banks of synchronous SRAM
    (Vendetta) reserved
 4    (Viper only) enable fast BRDY# generation for PCI cycles
 3    (Viper only) enable fast FRAME# generation for PCI cycles
 2    (Viper only) byte merging/piping control
    0 no pipelining when byte merging is on
    1 pipelining enabled along with byte merging
 1    pipelined synchronous SRAM support; this bit is applicable only if
      register 11h bit 3 is set
    0 standard synchronous SRAM installed (Viper only)
    1 pipelined synchronous SRAM installed
 0    Cyrix linear burst mode support
    0 normal Intel standard burst mode
    1 support for Cyrix linear burst mode
SeeAlso: #P0189,#P0214,#P0219

Bitfields for OPTi "Viper"/"Vendetta" Tristate Control register:
Bit(s)    Description    (Table P0217)
  7    (Viper) reserved; must be written to 0
    (Vendetta) ISA retry (1)
 6    (Viper) reserved; must be written to 0
    (Vendetta) RAS line drive strength
        0 = 16 mA
        1 =     4 mA
 5    (Viper) voltage selection for the CAS# lines 7-0
        0 CAS# lines 7-0 are driven out at 5.0V logic level
        1 CAS# lines 7-0 are driven out at 3.3V logic level
    (Vendetta) CAS1# and CAS5# drive strength
        0 =     8 mA
        1 = 16 mA
 4    (Viper) programmable current drive for the MA[X], RAS[X]# and the DWE#
      lines
    (Vendetta) memory address lines and write enable line drive strength
    0 driving capability on these lines is 4mA
    1 driving capability on these lines is 16mA
 3    enable tristate CPU interface during Suspend and during CPU power-off
 2    enable tristate PCI interface during Suspend and during PCI power-off
 1    enable tristate cache interface during Suspend and cache power-off
 0    enable the pull-up/pull-down resistors during Suspend and power-off
SeeAlso: #P0189,#P0219

Bitfields for OPTi "Viper" (82C557) Memory Decode Control register 3:
Bit(s)    Description    (Table P0218)
 7    DIRTYWE# RAS5# selection; if six DRAM banks are chosen, then the line
      will become RAS#5, if this bit is set
    0 DIRTYWE# functions as DIRTYWE# (six banks of DRAM are not chosen)
    1 DIRTYWE# functions as RAS#5 (six banks of DRAM are chosen)
    (Vendetta must be set to RAS5# function (1))
 6-4    (Viper) full decode for logical bank 5 (RAS#5) if register 13h bit 7
      and register 19h bit 7 are set (see #P0212)
    (Vendetta) full decode for logical bank 5 (RAS5#) if register 13h
      bit 7 set (see #P0212)
 3    MA11/RAS#4 selection; if five DRAM banks are chosen, then the MA11 line
      will become RAS#4, if this bit is set
    0 MA11 functions as MA11 (the fifth bank of DRAM is not chosen)
    1 MA11 functions as RAS#4 (five banks of DRAM have been chosen)
    (Vendetta must be set to RAS4# function (1))
 2-0    (Viper) full decode for logical bank 4 (RAS#4) if register 13h bit 7
      and register 19h bit 3 are set (see #P0212)
    (Vendetta) full decode for logical bank 4 (RAS4#) if register 13h
      bit 7 set (see #P0212)
Notes:    (Viper) if bit 7 is set, then a combined Dirty/Tag SRAM solution must
       be implemented or else it will not have a Dirty RAM
    (Viper) if bit 3 is set, then none of the DRAM banks will support the
      8M*36 or 16M*36 options
SeeAlso: #P0189,#P0219
----------P00220024--------------------------
PORT 0022-0024 - OPTi "Vendetta" (82C750) CHIPSET - SYSTEM CONTROL REGISTERS
Note:    every access to PORT 0024h must be preceded by a write to PORT 0022h,
      even if the same register is being accessed a second time
SeeAlso: PORT 0022h"82C206"

0022  ?W  index for accesses to data port (see #P0219)
0023  RW  DMA clock select (see #P0087)
0024  RW  chip set data

(Table P0219)
Values for OPTi "Vendetta" (82C750) system control registers:
 00h    DRAM control register 1 (see #P0220)
 01h    DRAM control register 2 (see #P0192)
 02h    cache control register 1 (see #P0193)
 03h    cache control 2 (see #P0194)
 04h    shadow RAM control register 1 (see #P0195)
 05h    shadow RAM control register 2 (see #P0197)
 06h    shadow RAM control register 3 (see #P0198)
 07h    tag test register (see #P0199)
 08h    CPU cache control register (see #P0200)
 09h    system memory function register (see #P0201)
 0Ah    DRAM hole A address decode register 1 (see #P0202)
 0Bh    DRAM hole B address decode register 2 (see #P0203)
 0Ch    DRAM hole higher address (see #P0204)
 0Dh    clock control register (see #P0205)
 0Eh    PCI master burst control register 1 (see #P0206)
 0Fh    PCI master burst control register 2 (see #P0207)
 10h    miscellaneous control register 1 (see #P0208)
 11h    miscellaneous control register 2 (see #P0209)
 12h    miscellaneous control register 3 (see #P0221)
 13h    memory decode control register 1 (see #P0211)
 14h    memory decode control register 2 (see #P0213)
 15h    PCI cycle control register 1 (see #P0214)
 16h    dirty/tag RAM control register (see #P0215)
 17h    PCI cycle control register 2 (see #P0216)
 18h    tristate control register (see #P0217)
 19h    memory decode control register 3 (see #P0218)
 1Ah    memory shadow control register 1 (see #P0222)
 1Bh    memory shadow control register 2 (see #P0223)
 1Ch    EDO SDRAM control register (see #P0224)
 1Dh    miscellaneous control register 4 (see #P0225)
 1Eh    BOFF# control register (see #P0226)
 1Fh    EDO timing control register (see #P0227)
 20h    DRAM burst control register (see #P0228)
 21h    PCI concurrence control register (see #P0229)
 22h    inquire cycle control register (see #P0230)
 23h    pre-snoop control register (see #P0231)
 24h    asymmetric DRAM configuration register (see #P0232)
 25h    GUI memory location register (see #P0233)
 26h    UMA control register (see #P0234)
 27h    self refresh timing register (see #P0235)
 28h    SDRAM burst and latency control register (see #P0236)
 29h    SDRAM selection register (see #P0237)
 2Ah    PCI-to-DRAM deep buffer size register (see #P0238)
 2Bh    EDO/SDRAM time-out register (see #P0239)
 2Ch    CPU-to-DRAM buffer control register (see #P0240)
 2Dh    bank-wise EDO timing selection register (see #P0241)
 2Eh    PCI master - GUI retry control register (see #P0242)
 2Fh    CAS address setup time control register (see #P0243)
 30h-7Fh reserved
 80h    PIC 1 ICW1 read-back register (read-only)
 81h    PIC 1 ICW2 read-back register (read-only)
 82h    PIC 1 ICW3 read-back register (read-only)
 83h    PIC 1 ICW4 read-back register (read-only)
 84h    reserved
 85h    PIC 1 OCW2 read-back register (read-only)
 86h    PIC 1 OCW3 read-back register (read-only)
 87h    reserved
 88h    PIC 2 ICW1 read-back register (read-only)
 89h    PIC 2 ICW2 read-back register (read-only)
 8Ah    PIC 2 ICW3 read-back register (read-only)
 8Bh    PIC 2 ICW4 read-back register (read-only)
 8Ch    reserved
 8Dh    PIC 2 OCW2 read-back register (read-only)
 8Eh    PIC 2 OCW3 read-back register (read-only)
 8Fh    refresh address register (see #P0244)
 90h    CTSC0LB (PIT counter 0 low byte) read-back register (read-only)
 91h    CTSC0HB (PIT counter 0 high byte) read-back register (read-only)
 92h    CTSC1LB (PIT counter 1 low byte) read-back register (read-only)
 93h    CTSC1HB (PIT counter 1 high byte) read-back register (read-only)
 94h    CTSC2LB (PIT counter 2 low byte) read-back register (read-only)
 95h    CTSC2HB (PIT counter 2 high byte) read-back register (read-only)
 96h    byte pointer register (read-only)
    (byte 2 pointer value)
 97h-ACh reserved
 ADh    general purpose chip select control register (see #P0270)
 AEh-DFh reserved
 E0h    GREEN mode control/enable status (see #P0245)
 E1h    EPMI control/GREEN event timer (see #P0246)
 E2h    GREEN event timer initial count register (see #P0247)
 E3h    IRQ event enable register 1 (see #P0248)
 E4h    IRQ event enable register 2 (see #P0249)
 E5h    DREQ event enable register (see #P0250)
 E6h    device cycle monitor enable register (see #P0251)
 E7h    wake-up source/programmable IO/memory address mask register (see #P0252)
 E8h    programmable I/O/MEM address range register (see #P0253)
 E9h    programmable I/O/MEM address range register (see #P0254)
 EAh    enter GREEN state port register (see #P0255)
 EBh    return to NORMAL state configuration port register (see #P0256)
 ECh    shadow register for external power control latch register (see #P0257)
 EDh    device cycle detection enable/status register (see #P0258)
 EEh    STPCLK# modulation register (see #P0259)
 EFh    miscellaneous register (see #P0260)
 F0h    device timer CLK select/enable status register (see #P0261)
 F1h    device timer 0 initial count register
 F2h    device timer 1 initial count register
 F3h    device timer IO/MEM select, mask bits register (see #P0262)
 F4h    device 0 IO/MEM address register (see #P0263)
 F5h    device 0 IO/MEM address register (see #P0264)
 F6h    device 1 IO/MEM address register (see #P0265)
 F7h    device 1 IO/MEM address register (see #P0266)
 FAh-FBh reserved
 FCh    power management control register 1 (see #P0267)
 FDh    power management control register 2 (see #P0268)
 FEh    power management control register 3 (see #P0269)
 FFh    general purpose chip select control register (see #P0270)

Bitfields for OPTi "Vendetta" DRAM control register 1:
Bit(s)    Description    (Table P0220)
 7    reserved
 6    SDRAM pipeline fix (1)
 5-0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" miscellaneous control register 3:
Bit(s)    Description    (Table P0221)
 7    buffered DMA register 8Fh latch to bits 23-16 of SA lines disable
 6-0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" memory shadow control register 1:
Bit(s)    Description    (Table P0222)
 7    reserved
 6-5    CPU bus utilization time guarantee
    00 = no guarantee
    01 = 1 of every 15 microseconds
    10 = 2 of every 15 microseconds
    11 = 4 of every 15 microseconds
 4    C8000-DFFFF shadow granularity
    0 = 16 KB
    1 =  8 KB
 3-2    CE000-CFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if bit 4 is set (see #P0196)
 1-0    CA000-CBFFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if bit 4 is set (see #P0196)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" memory shadow control register 2:
Bit(s)    Description    (Table P0223)
 7-6    DE000-DFFFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if register 1Ah bit 4 is set
      (see #P0196)
 5-4    DA000-DBFFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if register 1Ah bit 4 is set
      (see #P0196)
 3-2    D6000-D7FFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if register 1Ah bit 4 is set
      (see #P0196)
 1-0    D2000-D3FFF read/write control; determines the R/W control for these
      segments of the shadow RAM; applicable if register 1Ah bit 4 is set
      (see #P0196)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" EDO SDRAM control register:
Bit(s)    Description    (Table P0224)
 7-2    bank 5-0 EDO SDRAM usage
    0 = standard page mode DRAM
    1 = EDO SDRAM
 1    reserved
 0    DRAM access CAS pulse width
    0 = determined by register 01h bit 3
    1 = 1 CPUCLK
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" miscellaneous control register 4:
Bit(s)    Description    (Table P0225)
 7-6    reserved
 5    DWE# timing
    0 = normal
    1 = removed 1 CLK earlier
 4    DRAM read leadoff cycle
    0 = normal
    1 = 1 CLK reduced
 3    system memory DMA access disable
 2    reserved
 1    SMM mode B0000-BFFFF access
    0 = main memory
    1 = PCI bus
 0    SMM mode A0000-AFFFF access
    0 = main memory
    1 = PCI bus
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" BOFF# control register:
Bit(s)    Description    (Table P0226)
 7    PCI master read cycle
    0 = wait IRDY# assert before TRDY# assert
    1 = generate TRDY# when checking IRDY# status
 6    reserved (1)
 5    reserved
 4    A0000-BFFFF PCI retry cycle BOFF# generation
    0 = not generated if bit 3 set
    1 = generated if bit 3 set
 3    deadlock situation avert
    0 = no avert
    1 = assert BOFF#
 2    reserved (1)
 1-0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" EDO timing control register:
Bit(s)    Description    (Table P0227)
 7    0 = normal
    1 = EDO detection conflict generation (bit 6 set)
 6    0 = normal fast page mode
    1 = detect EDO
 5    NA# generation
    0 = aggresive
    1 = normal
 4    DRAM read cycle lead-off 1 CLK reduce enable
 3-2    reserved
 1    hidden refresh block AHOLD disable
 0    D0000-DFFFF cacheable in L1 and L2
    0 = not cacheable
    1 = cacheable; area has to be read/writable and shadowed
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" DRAM burst control register:
Bit(s)    Description    (Table P0228)
 7    reserved (1)
 6    PCI master access HITM# cycle DRAM write post enable
 5    reserved
 4    PCI master parity enable
 3-2    PCI master cycle DRAM write burst cycle
    00 = reserved
    01 = X-3-3-3
    10 = X-2-2-2
    11 = X-1-1-1
 1-0    PCI master cycle DRAM read burst cycle
    00 = reserved
    01 = X-3-3-3
    10 = X-2-2-2
    11 = X-1-1-1
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" PCI concurrence control register:
Bit(s)    Description    (Table P0229)
 7    concurrence timer
    0 = conservative
    1 = aggressive
 6-5    PCI master and CPU/L2 concurrence
    00 = no concurrence
    x1 = PCI write invalid cycles
    1x = PCI read multiple and read line cycles
 4-3    reserved
 2    0 = if tag = 11011111b => invalid combination
    1 = if cache = 256K, tag = 00001100b => invalid combination (CF0000h).
        if cache > 256K, tag = 10111111b => invalid combination
      (valid only when bit 1 set)
 1-0    reserved (1)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" inquire cycle control register:
Bit(s)    Description    (Table P0230)
 7    reserved
 6-5    new mode pre-snoop function
    00 = disable
    11 = enable
 4    HRQ synchronous to LCLK enable (must be 1 for ISA retry)
 3-1    reserved
 0    write hit cycle lead-off time when combining Dirty/Tag RAM
    0 = single write hit lead-off cycle = 5 cycles
    1 = single write hit lead-off cycle = 4 cycles
Note:    bit 0 should be set same as register 16h bit 4
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" pre-snoop control register:
Bit(s)    Description    (Table P0231)
 7    reserved
 6    0 = bank 0 selected as first bank
    1 = bank 0 selected as last bank
 5    PCI X-1-1-1 write invalidate pre-snoop enable
 4    PCI X-1-1-1 read multiple and read line pre-snoop enable
 3    fast NA cache hit half clock shift enable
 2-1    reserved (1)
 0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" asymmetric DRAM configuration register:
Bit(s)    Description    (Table P0232)
 7-6    logical bank 3 DRAM type
    00 = symmetric
    01 = asymmetric x8
    10 = asymmetric x9
    11 = asymmetric x10
 5-4    logical bank 2 DRAM type
 3-2    logical bank 1 DRAM type
 1-0    logical bank 0 DRAM type
Note:    banks 4 and 5 do not support asymmetric DRAM
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" GUI memory location register:
Bit(s)    Description    (Table P0233)
 7-3    GUI memory location bits 31-27
 2    UMA size
    0 = decided by register 26h bits 5-4
    1 = 0.5MB (register 26h bits 5-4 = 00)
 1-0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" UMA control register:
Bit(s)    Description    (Table P0234)
 7    ISA master to DRAM cycle CAS width
    0 = controlled by ISA read/write command pulse width
    1 = 2 LCLKs
 6    ISA SA address latch
    0 = pass-through
    1 = on only for retry
 5-4    GUI memory size
    00 = 1MB (0.5MB if register 25h bit 2 set)
    01 = 2MB
    10 = 3MB
    11 = 4MB
 3    66MHz 5-2-2-2 EDO DRAM read timing enable
 2-1    GUI priority
    00 = normal
    01 = wait 2 CLKs for low priority GUI request
    11 = high
 0    UMA support enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" self refresh timing register:
Bit(s)    Description    (Table P0235)
 7-6    reserved
 5    PCI master write line invalid cycle HITM# or L2 dirty no stop enable
 4    CPU single write hit not dirty cycle second T2 AHOLD generate enable
 3    fast NA# with L2 cache enable
 2-0    self refresh
    000 = disable, use external refresh pin
    001-011 = reserved
    100 = 66MHz external CPU clock
    101 = 60MHz external CPU clock
    110 = 50MHz external CPU clock
    111 = 40MHz external CPU clock
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" SDRAM burst and latency control register:
Bit(s)    Description    (Table P0236)
 7    CS# delay enable
 6-4    SDRAM CAS# latency
    000 = reserved
    001 = 1
    010 = 2
    011 = 3
    100-111 = reserved
 3    0 = sequential write-through
    1 = interleaved write-through
 2-0    SDRAM burst length
    000 = 1
    001 = reserved
    010 = 4
    011-111 = reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" SDRAM selection register:
Bit(s)    Description    (Table P0237)
 7    pipeline read
    0 = 7-1-1-1-5-1-1-1-1
    1 = 7-1-1-1-2-1-1-1-1
 6    reserved
 5    timing
         tRP     tRAS    tMRS
    00 = 2 CLKs  4 CLKs  3 CLKs
    01 = 4 CLKs  5 CLKs  3 CLKs
    10 = 3 CLKs  6 CLKs  2 CLKs
    11 = rsvd    7 CLKs  rsvd
    tRP: command activate precharge time
    tRAS: command precharge RAS active time
    tMRS: mode register set cycle time
 4-0    bank 4-0 SDRAM enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" PCI-to-DRAM deep buffer size register:
Bit(s)    Description    (Table P0238)
 7    reserved
 6-5    PCI master read cycle GUI request time-out
    00 = FP mode, grant DRAM bus when possible
    01 = SDRAM or EDO time-out
    10-11 = FP mode, SDRAM, or EDO time-out
 4    PCI-to-DRAM deep buffer PCI TRDY# wait state
    0 = 0 wait state (X-1-1-1)
    1 = 1 wait state (X-2-2-2)
 3    PCI-to-DRAM deep buffer write burst enable
 2    PCI-to-DRAM deep buffer read burst enable
 1-0    PCI-to-DRAM deep buffer size
    00 = 16 dwords
    01 = 24 dwords
    10-11 = reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" EDO/SDRAM time-out register:
Bit(s)    Description    (Table P0239)
 7-4    SDRAM time-out count on GUI request - 9 CLKs
      (delay count +9 CLKs)
 3-0    EDO time-out count on GUI request
      (delay count +6 CLKs)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" CPU-to-DRAM buffer control register:
Bit(s)    Description    (Table P0240)
 7    concurrent CPU-to-PCI read and CPU-to-DRAM write enable
 6    reserved
 5    cache miss dirty cycle CPU-to-DRAM buffer control
    1 = supply data to CPU before previous data write-back
      (CPU-to-DRAM buffer must be enabled)
 4-3    reserved
 2    DRAM read cycle BOFF# assert enable
 1    CPU DRAM bus ownership data merge enable
 0    write data while buffer flush enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" bank-wise EDO timing selection register:
Bit(s)    Description    (Table P0241)
 7    reserved
 6    predictive reading enable
 5-0    bank 5-0 EDO DRAM read cycle
    0 = default
    1 = 5-X-X-X (66MHz)/4-X-X-X (50MHz) enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" PCI master - GUI retry control register:
Bit(s)    Description    (Table P0242)
 7-6    reserved
 5    USB module enable
 4    reserved
 3    CPU-to-PCI FIFO control module enable
 2    reserved
 1    PCI master HITM# cycle, GUI high priority request before first BRDY#
    0 = retry all
    1 = retry only PCI master read
 0    GUI cycle PCI master request retry
    0 = retry all
    1 = retry reads, accept writes
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" CAS address setup time control register:
Bit(s)    Description    (Table P0243)
 7    page miss cycle CAS column address delay
    0 = default
    1 = 1 CLK
 6    burst mode and length
 5    reserved
 4-3    burst mode and length
    bits 6 and 4-3:
    000 = mode 0, RWM 5
    001 = mode 1, RWM 5, BLEN 2
    010 = BLEN 3
    011 = BLEN 4
    100 = mode 0, RWM 4
    101 = mode 2, RWM 4, BLEN 1
    110 = BLEN 2
    111 = BLEN 3
    RWM: refresh request water mark
    BLEN: minimum number of burst refresh cycles
    mode 0: generate refresh request on RWM reach/cross; if high priority
        GUI request pending, preempt refresh burst at end of current
        cycle; if CPU/PCI request pending, preempt refresh burst when
        count<RWM; else refresh until count=0, then refresh ahead up
        to 3/7
    mode 1: generate refresh request on RWM reach/cross; if high priority
        GUI request pending, preempt refresh burst at end of current
        cycle; if CPU/PCI request pending, preempt refresh burst when
        count<RWM and performed refresh cycles>=BLEN; else refresh
        until count=0, then refresh ahead up to 3/7
    mode 2: generate refresh request on RWM reach/cross; if high priority
        GUI request pending, preempt refresh burst at end of current
        cycle; if CPU request pending, preempt refresh burst when
        performed refresh cycles>=BLEN; if PCI request pending,
        preempt refresh burst when count<RWM and performed refresh
        cycles>=BLEN; else refresh until count=0, then refresh ahead
        up to 3/7
 2-0    refresh ahead
    000 = burst refresh disable
    001 = starting bank 0, no refresh ahead
    010 = starting bank 0, refresh ahead up to 3
    011 = starting bank 0, refresh ahead up to 7
    100 = burst refresh disable
    101 = starting bank dynamic, no refresh ahead
    110 = starting bank dynamic, refresh ahead up to 3
    111 = starting bank dynamic, refresh ahead up to 7
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" refresh address register:
Bit(s)    Description    (Table P0244)
 7-0    during buffered DMA cycle reflected on bits 23-16 of SA lines,
      bits 15-10 of SA lines cleared
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" GREEN mode control/enable status:
Bit(s)    Description    (Table P0245)
 7    power management SMI# generation enable
 6    GREEN event SMI# generation
    (read)
    0 = GREEN event did not generate SMI#
    1 = GREEN event generated SMI#
    (write)
    0 = disable GREEN event SMI# generation
    1 = enable GREEN event SMI# generation (if bit 7 set)
 5    reload GREEN event timer/wake-up event SMI# generation
    (read)
    0 = wake-up event did not generate SMI#
    1 = wake-up event generated SMI#
    (write)
    0 = disable wake-up event SMI# generation
    1 = enable wake-up event SMI# generation (if bit 7 set)
 4    power management status (read-only)
    0 = NORMAL
    1 = GREEN
 3    power management PPWRL# generation enable
 2    GREEN event PPWRL# generation enable (if bit 3 set)
 1    reload GREEN event timer/wake-up event PPWRL# generation enable
      (if bit 3 set)
 0    software generation of GREEN event
    0 = no action
    1 = generate GREEN event (if register E1h bit 0 set)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" EPMI control/GREEN event timer:
Bit(s)    Description    (Table P0246)
 7-6    GREEN event timer CLK period
    00 = 119 microseconds
    01 = 12.25 ms
    10 = 1.94 s
    11 = 62.5 s
 5    EPMI0# polarity
    0 = EPMI0# triggered on falling edge
    1 = EPMI0# triggered on rising edge
 4    EPMI0# debounce enable
 3    EPMI0# polarity
    0 = determined by bit 5
    1 = EPMI0# triggered on transition
 2    GREEN event timer time-out GREEN event generation
    (read)
    0 = GREEN event timer time-out did not cause GREEN event
    1 = GREEN event timer time-out did cause GREEN event
    (write)
    0 = disable GREEN event timer time-out GREEN event generation
    1 = enable GREEN event timer time-out GREEN event generation
 1    EPMI0# trigger GREEN event generation
    (read)
    0 = EPMI0# trigger did not cause GREEN event
    1 = EPMI0# trigger did cause GREEN event
    (write)
    0 = disable EPMI0# trigger GREEN event generation
    1 = enable EPMI0# trigger GREEN event generation
 0    software trigger GREEN event generation
    (read)
    0 = software trigger did not cause GREEN event
    1 = software trigger did cause GREEN event
    (write)
    0 = disable software trigger GREEN event generation
    1 = enable software trigger GREEN event generation
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" GREEN event timer initial count register:
Bit(s)    Description    (Table P0247)
 7-0    time-out timer count - 2
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" IRQ event enable register 1:
Bit(s)    Description    (Table P0248)
 7-3    IRQ7-IRQ3 monitoring enable
 2    IRQ15-IRQ0 deglitch enable
 1-0    IRQ1-IRQ0 monitoring enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" IRQ event enable register 2:
Bit(s)    Description    (Table P0249)
 7-0    IRQ15-IRQ8 monitoring enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" DREQ event enable register:
Bit(s)    Description    (Table P0250)
 7-5    DREQ7-DREQ5 monitoring enable (if register EFh bit 6 set)
 4    reserved
 3-0    DREQ3-DREQ0 monitoring enable (if register EFh bit 6 set)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device cycle monitor enable register:
Bit(s)    Description    (Table P0251)
 7    programmable IO/MEM monitoring enable
 6    parallel ports monitoring enable
 5    video monitoring enable
 4    hard disk monitoring enable
 3    floppy disk monitoring enable
 2    keyboard monitoring enable
 1    COM1/COM3 monitoring enable
 0    COM2/COM4 monitoring enable
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" wake-up source/programmable IO/memory address:
Bit(s)    Description    (Table P0252)
 7    PREQ# monitoring enable (if register EFh bit 7 set)
 6    LDEV#/DEVSEL# monitoring enable
 5    EPMI0# trigger monitoring enable
 4    reserved
 3    programmable IO/MEM address type
    0 = I/O
    1 = non-system memory
 2-0    programmable IO/MEM address mask bits 2-0 (bit 3 = register FFh bit 0)
      (mask lowest n bits)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" programmable I/O/MEM address range register:
Bit(s)    Description    (Table P0253)
 7-0    I/O address bits 7-0 or non-system memory address bits 23-16
      (use register E7h bit 3 to select I/O or non-system memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" programmable I/O/MEM address range register:
Bit(s)    Description    (Table P0254)
 7-0    I/O address bits 15-8 or non-system memory address bits 31-24
      (use register E7h bit 3 to select I/O or non-system memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" enter GREEN state port register:
Bit(s)    Description    (Table P0255)
 7-0    GREEN state values for external power control latch
      (transfered to register ECh on enter GREEN state PPWRL#)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" return to NORMAL state configuration port:
Bit(s)    Description    (Table P0256)
 7-0    NORMAL state values for external power control latch
      (transfered to register ECh on return to NORMAL state PPWRL#)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" shadow register for external power control latch:
Bit(s)    Description    (Table P0257)
 7-0    external power control latch value
      (write generates PPWRL#)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device cycle detection enable/status register:
Bit(s)    Description    (Table P0258)
 7    programmed range access SMI# generation
    (read)
    0 = programmed range access did not generate SMI#
    1 = programmed range access generated SMI#
    (write)
    0 = disable programmed range access SMI# generation
    1 = enable programmed range access SMI# generation
 6    LPT access SMI# generation
    (read)
    0 = LPT access did not generate SMI#
    1 = LPT access generated SMI#
    (write)
    0 = disable LPT access SMI# generation
    1 = enable LPT access SMI# generation
 5    video access SMI# generation
    (read)
    0 = video access did not generate SMI#
    1 = video access generated SMI#
    (write)
    0 = disable video access SMI# generation
    1 = enable video access SMI# generation
 4    hard disk access SMI# generation
    (read)
    0 = hard disk access did not generate SMI#
    1 = hard disk access to generated SMI#
    (write)
    0 = disable hard disk access SMI# generation
    1 = enable hard disk access SMI# generation
 3    floppy disk access SMI# generation
    (read)
    0 = floppy disk access did not generate SMI#
    1 = floppy disk access generated SMI#
    (write)
    0 = disable floppy disk access SMI# generation
    1 = enable floppy disk access SMI# generation
 2    keyboard access SMI# generation
    (read)
    0 = keyboard access did not generate SMI#
    1 = keyboard access generated SMI#
    (write)
    0 = disable keyboard access SMI# generation
    1 = enable keyboard access SMI# generation
 1    COM1/COM3 access SMI# generation
    (read)
    0 = COM1/COM3 access did not generate SMI#
    1 = COM1/COM3 access generated SMI#
    (write)
    0 = disable COM1/COM3 access SMI# generation
    1 = enable COM1/COM3 access SMI# generation
 0    COM2/COM4 access SMI# generation
    (read)
    0 = COM2/COM4 access did not generate SMI#
    1 = COM2/COM4 access generated SMI#
    (write)
    0 = disable COM2/COM4 access SMI# generation
    1 = enable COM2/COM4 access SMI# generation
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" STPCLK# modulation register:
Bit(s)    Description    (Table P0259)
 7    CPU STOPCLK state support enable
 6    STOPCLK state CPU hold enable
 5-4    reserved
 3    STPCLK# modulation enable
 2-0    STPCLK# modulation duty cycle; in effect if bit 3 set
    000 = STPCLK# = 1 always (no modulation)
    001 = STPCLK# = 1 for 1/2 period
    010 = STPCLK# = 1 for 1/4 period
    011 = STPCLK# = 1 for 1/8 period
    100 = STPCLK# = 1 for 1/16 period
    101-111 = reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" miscellaneous register:
Bit(s)    Description    (Table P0260)
 7    PREQ# wake-up enable
 6    DREQ# wake-up enable
 5    reserved
 4    GPCS1# and GPCS#2 generation for addresses in registers F4h-F7h enable
 3    reserved
 2    PPWRL# inititiate clock
    0 = 14 MHz
    1 = 33 KHz
 1    timer count read (registers E0h-E2h, EDh, F0h-F2h, FCh-FEh)
    0 = return current value
    1 = return original value
 0    reserved
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device timer CLK select/enable status register:
Bit(s)    Description    (Table P0261)
 7-6    device timer 1 CLK period
    00 = 119 microseconds
    01 = 12.25 ms
    10 = 1.94 s
    11 = 62.5 s
 5-4    device timer 0 CLK period
    00 = 119 microseconds
    01 = 12.25 ms
    10 = 1.94 s
    11 = 62.5 s
 3    device timer 1 time-out GREEN event generation
    (read)
    0 = device timer 1 time-out did not cause GREEN event
    1 = device timer 1 time-out did cause GREEN event
    (write)
    0 = disable device timer 1 time-out GREEN event generation
    1 = enable device timer 1 time-out GREEN event generation
 2    device timer 0 time-out GREEN event generation
    (read)
    0 = device timer 0 time-out did not cause GREEN event
    1 = device timer 0 time-out did cause GREEN event
    (write)
    0 = disable device timer 0 time-out GREEN event generation
    1 = enable device timer 0 time-out GREEN event generation
 1    device 1 access wake-up event generation
    (read)
    0 = device 1 access did not cause wake-up event
    1 = device 1 access did cause wake-up event
    (write)
    0 = disable device 1 access wake-up event generation
    1 = enable device 1 access wake-up event generation
 0    device 0 access wake-up event generation
    (read)
    0 = device 0 access did not cause wake-up event
    1 = device 0 access did cause wake-up event
    (write)
    0 = disable device 0 access wake-up event generation
    1 = enable device 0 access wake-up event generation
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device timer IO/MEM select, mask bits register:
Bit(s)    Description    (Table P0262)
 7    device 1 address type
    0 = I/O
    1 = memory
 6-4    device 1 IO/MEM address mask bits 2-0 (bit 3 = register FFh bit 2)
      (mask lowest n bits)
 3    device 0 address type
    0 = I/O
    1 = memory
 2-0    device 0 IO/MEM address mask bits 2-0 (bit 3 = register FFh bit 2)
      (mask lowest n bits)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device 0 IO/MEM address register:
Bit(s)    Description    (Table P0263)
 7-0    I/O address bits 7-0 or memory address bits 23-16
      (use register F3h bit 3 to select I/O or memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device 0 IO/MEM address register:
Bit(s)    Description    (Table P0264)
 7-0    I/O address bits 15-8 or memory address bits 31-24
      (use register F3h bit 3 to select I/O or memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device 1 IO/MEM address register:
Bit(s)    Description    (Table P0265)
 7-0    I/O address bits 7-0 or memory address bits 23-16
      (use register F3h bit 7 to select I/O or memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" device 1 IO/MEM address register:
Bit(s)    Description    (Table P0266)
 7-0    I/O address bits 15-8 or memory address bits 31-24
      (use register F3h bit 7 to select I/O or memory address)
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" power management control register 1:
Bit(s)    Description    (Table P0267)
 7    EPMI1# GREEN event generation
    (read)
    0 = EPMI1# did not cause GREEN event
    1 = EPMI1# caused GREEN event
    (write)
    0 = disable EPMI1# GREEN event generation
    1 = enable EPMI1# GREEN event generation
 6    EPMI1# reload wake-up GREEN state timer enable
 5    EPMI1# polarity
    0 = determined by bit 4
    1 = EPMI1# triggered on transition
 4    EPMI1# polarity
    0 = EPMI1# triggered on falling edge
    1 = EPMI1# triggered on rising edge
 3    EPMI1# debounce enable
 2-0    reserved
Note:    bits 7 and 6 cannot both be set at the same time
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" power management control register 2:
Bit(s)    Description    (Table P0268)
 7    EPMI2# GREEN event generation
    (read)
    0 = EPMI2# did not cause GREEN event
    1 = EPMI2# caused GREEN event
    (write)
    0 = disable EPMI2# GREEN event generation
    1 = enable EPMI2# GREEN event generation
 6    EPMI2# reload wake-up GREEN state timer enable
 5    EPMI2# polarity
    0 = determined by bit 4
    1 = EPMI2# triggered on transition
 4    EPMI2# polarity
    0 = EPMI2# triggered on falling edge
    1 = EPMI2# triggered on rising edge
 3    EPMI2# debounce enable
 2-0    reserved
Note:    bits 7 and 6 cannot both be set at the same time
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" power management control register 3:
Bit(s)    Description    (Table P0269)
 7    EPMI3# GREEN event generation
    (read)
    0 = EPMI3# did not cause GREEN event
    1 = EPMI3# caused GREEN event
    (write)
    0 = disable EPMI3# GREEN event generation
    1 = enable EPMI3# GREEN event generation
 6    EPMI3# reload wake-up GREEN state timer enable
 5    EPMI3# polarity
    0 = determined by bit 4
    1 = EPMI3# triggered on transition
 4    EPMI3# polarity
    0 = EPMI3# triggered on falling edge
    1 = EPMI3# triggered on rising edge
 3    EPMI3# debounce enable
 2-0    reserved
Note:    bits 7 and 6 cannot both be set at the same time
SeeAlso: #P0219

Bitfields for OPTi "Vendetta" general purpose chip select control register:
Bit(s)    Description    (Table P0270)
 7    CPU type
    0 = Intel/AMD
    1 = Cyrix M1
 6    reserved
 5-4    IDE module device ID
    00 = C621h
    01 = D568h
    10 = D768h (ultra DMA)
    11 = reserved
 3    reserved
 2    GPCS2# address bit masking (fourth bit to register F3h bits 6-4)
 1    GPCS1# address bit masking (fourth bit to register F3h bits 2-0)
 0    GPCS0# address bit masking (fourth bit to register E7h bits 2-0)
Note:    indexes ADh and FFh address same register
SeeAlso: #P0219
----------P00220025--------------------------
PORT 0022-0025 - INTEL 82360SL CHIPSET (FOR 386SL)

0022  -W  CPU write mode register
0023  R-  configuration status register
        bit 7: 82360 configuration is open
0024  -W  82360 configuration index
0025  RW  82360 configuration data

Bitfields for Intel 82360SL CPU write mode register:
Bit(s)    Description    (Table P0271)
 0    unlock configuration space
 1    enable selected unit
 3-2    unit
    00 memory configuration
    01 cache
    10 internal bus
    11 external bus
----------P0022002B--------------------------
PORT 0022-002B - INTEL 82355, PART OF CHIPSET FOR 386sx
Note:    initialisation in POST will disable these addresses, only a hard
      reset will enable them again.

0022w RW  82335 MCR memory configuration register (if LOCK=0) (see #P0272)
0024w RW  82335 RC1 roll compare register (if LOCK=0) (see #P0273)
0026w RW  82335 RC2 roll compare register (if LOCK=0) (see #P0273)
0028w RW  82335 CC0 address range compare register (if LOCK=0) (see #P0274)
002Aw RW  82335 CC1 address range compare register (if LOCK=0) (see #P0274)

Bitfields for 82335 MCR memory configuration register:
Bit(s)    Description    (Table P0272)
 15-12    reserved
 11    "VRO"    video read only (0=r/w, 1=r/o)
 10    "EN#"
    0=enable video RAM accesses (A0000h-8FFFFh)
    1=disable accesses
 9    "ENADP#"
    0=enable adapter ROM accesses (C0000h-8FFFFh)
    1=disable adapter ROM accesses, shadow enabled
 8    "ROMSIZE" 0=256KB ROM, 1=512KB ROM
 7-6    "INTERL" memory interleaving
    00 = 1 memory bank installed (no interleave)
    01 = 2 memory banks installed
    10 = 3 memory banks installed
    11 = 4 memory banks installed
 5    reserved
 4    "DSIZE"     0=1MBx1DRAMs, 1=256KBx1 or 256KBx4 DRAMs
 3    "S640"     base memory size is 0=512KB, 1=640KB
 2-1    reserved
 0    "ROMEN#" ROM enable
    0 enable BIOS ROM accesses (E0000h-FFFFFh)
    1 disable BIOS ROM accesses, enable shadow
Note:    One of the remaining reserved bits is the LOCK bit, which will be set
      during power on, disabling access to the 82335s registers.

Bitfields for 82335 roll compare register:
Bit(s)    Description    (Table P0273)
 15-9    selects address range to be remapped (C23-C17)
 8    reserved
 7-1    selects address bits to be included in re-mapping comparision (M23-M17)
 0    "EN" enables roll address mapping

Bitfields for 82335 address range compare register:
Bit(s)    Description    (Table P0274)
 15-11    specifies top of address range (C23-C19)
 10-8    reserved
 7-3    selects address bits to be included in address range comparision
      (M23-M19)
 2-1    reserved
 0    "EN" enable address range comparision
----------P00240025--------------------------
PORT 0024-0025 - Intel 82091AA Advanced Integrated Peripheral
Range:    PORT 0022h (X-Bus), PORT 0024h (X-Bus), PORT 026Eh (ISA), or
      PORT 0398h (ISA)
SeeAlso: PORT 0022h"82091AA",PORT 026Eh"82091AA",PORT 0398h"82091AA"

0024  ?W  configuration register index
0025  RW  configuration register data
----------P00240026--------------------------
PORT 0024-0026 - PicoPower Vesuvius - V3-LS
Note:    software must use 8-bit accesses to these ports; 16-bit accesses will
      be directed to the V1-LS chip in the chipset instead of the V3-LS
SeeAlso: PORT 0024h"V1-LS"

0024b  ?W  V3-LS register index (see #P0275)
0026b  RW  V3-LS register data

(Table P0275)
Values for PicoPower Vesuvius V3-LS register index:
 00h    revision ID register (see #P0276)
 01h    AT control register 1 (see #P0277)
 02h    AT control register 2 (see #P0278)
 03h    BIOS CS# control register (see #P0279)
 05h    port 92h control register (see #P0280)
 06h    GPEXT low byte register (write high byte into register 07h before
      writing low byte)
 07h    GPEXT high byte register (write high byte before writing low byte into
      register 06h)
 08h    miscellaneous configuration register (see #P0281)
 10h    PCI interrupt mapping register 1 (see #P0282)
 11h    PCI interrupt mapping register 2 (see #P0283)
 12h    PCI INT# configuration register (see #P0284)
 13h    serial IRQ control register (see #P0285)
 14h    serial IRQ control register 2 (see #P0286)
 20h    power management control register (see #P0287)
 21h    primary activity IRQ mask register 1 (see #P0288)
 22h    primary activity IRQ mask register 2 (see #P0289)
 23h    PMI trigger IRQ mask register 1 (see #P0290)
 24h    PMI trigger IRQ mask register 2 (see #P0291)
 25h    PMI trigger source register 1 (see #P0292)
 26h    PMI trigger source register 2 (see #P0293)
 30h    8254 counter 0 initial count low byte shadow
 31h    8254 counter 0 initial count high byte shadow
 32h    8254 counter 1 initial count low byte shadow
 33h    8254 counter 1 initial count high byte shadow
 34h    8254 counter 2 initial count low byte shadow
 35h    8254 counter 2 initial count high byte shadow
 36h    8254 counter 0 control word shadow
 37h    8254 counter 1 control word shadow
 38h    8254 counter 2 control word shadow
 39h    8237 DMA controller mode register for channel 0 shadow
 3Ah    8237 DMA controller mode register for channel 1 shadow
 3Bh    8237 DMA controller mode register for channel 2 shadow
 3Ch    8237 DMA controller mode register for channel 3 shadow
 3Dh    8237 DMA controller mode register for channel 4 shadow
 3Eh    8237 DMA controller mode register for channel 5 shadow
 3Fh    8237 DMA controller mode register for channel 6 shadow
 40h    8237 DMA controller mode register for channel 7 shadow
 41h    8259 PIC 1 ICW 1 shadow
 42h    8259 PIC 1 ICW 2 shadow
 43h    8259 PIC 1 ICW 3 shadow
 44h    8259 PIC 1 ICW 4 shadow
 45h    8259 PIC 1 OCW 2 shadow
 46h    8259 PIC 1 OCW 3 shadow
 47h    8259 PIC 2 ICW 1 shadow
 48h    8259 PIC 2 ICW 2 shadow
 49h    8259 PIC 2 ICW 3 shadow
 4Ah    8259 PIC 2 ICW 4 shadow
 4Bh    8259 PIC 2 OCW 2 shadow
 4Ch    8259 PIC 2 OCW 3 shadow
 4Dh    RTC index register shadow
 4Eh    reserved
 4Fh    fixed disk register (port 3F6h) shadow
 50h    hard disk write precompression register (port 1F1h) shadow
 51h    DMA controller 1 status register shadow
 52h    DMA controller 2 status register shadow
 53h    DMAC mask register shadow
 54h    DMA channel 0 base address low byte shadow
 55h    DMA channel 0 base address high byte shadow
 56h    DMA channel 0 base count low byte shadow
 57h    DMA channel 0 base count high byte shadow
 58h    DMA channel 1 base address low byte shadow
 59h    DMA channel 1 base address high byte shadow
 5Ah    DMA channel 1 base count low byte shadow
 5Bh    DMA channel 1 base count high byte shadow
 5Ch    DMA channel 2 base address low byte shadow
 5Dh    DMA channel 2 base address high byte shadow
 5Eh    DMA channel 2 base count low byte shadow
 5Fh    DMA channel 2 base count high byte shadow
 60h    DMA channel 3 base address low byte shadow
 61h    DMA channel 3 base address high byte shadow
 62h    DMA channel 3 base count low byte shadow
 63h    DMA channel 3 base count high byte shadow
 64h    DMA channel 5 base address low byte shadow
 65h    DMA channel 5 base address high byte shadow
 66h    DMA channel 5 base count low byte shadow
 67h    DMA channel 5 base count high byte shadow
 68h    DMA channel 6 base address low byte shadow
 69h    DMA channel 6 base address high byte shadow
 6Ah    DMA channel 6 base count low byte shadow
 6Bh    DMA channel 6 base count high byte shadow
 6Ch    DMA channel 7 base address low byte shadow
 6Dh    DMA channel 7 base address high byte shadow
 6Eh    DMA channel 7 base count low byte shadow
 6Fh    DMA channel 7 base count high byte shadow
 70h    DMA controller 1 command register shadow
 71h    DMA controller 2 command register shadow
Note:    shadow registers (30h-71h) are read-only
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V3-LS revision ID register:
Bit(s)    Description    (Table P0276)
 7-4    V3-LS revision ID
    1h = revision A
    2h = revision B
    3h = revision C
 3-0    V3-LS metal-mask version ID
    0h = version A
    1h = version B
    3h = version C
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS AT control register 1:
Bit(s)    Description    (Table P0277)
 7-6    (revision BB and later) back-to-back delay for 8-bit I/O cycle
    00 = 0.5 SYSCLKs
    01 = 2.5 SYSCLKs
    10 = 4.5 SYSCLKs
    11 = 6.5 SYSCLKs
 5-4    (revision BB and later) back-to-back delay for 16-bit I/O cycle
    00 = 0.5 SYSCLKs
    01 = 1.5 SYSCLKs
    10 = 2.5 SYSCLKs
    11 = 3.5 SYSCLKs
 3    reserved
 2-0    SYSCLK divisor select
    000 = BSERCLK/2
    001 = BSERCLK/3
    010 = BSERCLK/4
    011 = BSERCLK/5
    100 = BSERCLK/6
    101-110 = reserved
    111 = 14MHZCLK/2
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS AT control register 2:
Bit(s)    Description    (Table P0278)
 7    reserved
 6    (revision BB and later) external keyboard chip select
    0 = ROM_KBCS# decodes ports 60h/64h as keyboard ports
    1 = ROM_KBCS# decodes ports 60h/62h/64h/66h as keyboard ports
 5-4    reserved
 3    (revision BB and later) EISA type CMOS RAM interface control enable
 2    (revision BB and later) V3-LS internal I/O port option
    0 = normal V3-LS internal I/O port access
    1 = speed up V3-LS internal I/O port access
 1    extended AT address
 0    AT bus refresh enable
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS BIOS CS# control register:
Bit(s)    Description    (Table P0279)
 7    reserved
 6    flash enable
 5    E8000h-EFFFFh ROMCS# enable
 4    E0000h-E7FFFh ROMCS# enable
 3    D8000h-DFFFFh ROMCS# enable
 2    D0000h-D7FFFh ROMCS# enable
 1    C8000h-CFFFFh ROMCS# enable
 0    C0000h-C7FFFh ROMCS# enable
Notes:    FE000000h-FFFFFFFFh access always generates ROMCS#
    F0000h-FFFFFh access generates ROMCS# if not shadowed
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS port 92h control register:
Bit(s)    Description    (Table P0280)
 7-2    reserved
 1    security lock 1 (port 92h bit 3) function enable
 0    port 92h enable
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS miscellaneous configuration register:
Bit(s)    Description    (Table P0281)
 7    reserved
 6    reserved (ISA master I/O command synchronizer disable)
 5    reserved (timer synchronous IOW# fix disable)
 4    reserved
 3    (revision BB and later) DDMA grant
    0 = V3-LS uses REQ#/GNT# for DDMA retry cycle
    1 = V3-LS does not use REQ#/GNT# for DDMA retry cycle
 2    BSER interrupt enable
 1    (revision BB and later) DDMARETRY
    0 = pin 44 (176-pin) / pin 48 (208-pin) is DDMA_RETRY
    1 = pin 44 (176-pin) / pin 48 (208-pin) is ISA_WAKE
 0    BSER arbitration enable
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS PCI interrupt mapping register 1:
Bit(s)    Description    (Table P0282)
 7-4    map INTB# to IRQ
    0000 = disabled
    0001-0010 = reserved
    0011-0111 = IRQ3-IRQ7
    1000 = reserved
    1001-1100 = IRQ9-IRQ12
    1101 = reserved
    1110-1111 = IRQ14-IRQ15
 3-0    map INTA# to IRQ (same values as bits 7-4)
SeeAlso: #P0275,#P0283

Bitfields for PicoPower Vesuvius V3-LS PCI interrupt mapping register 2:
Bit(s)    Description    (Table P0283)
 7-4    map INTD# to IRQ
    0000 = disabled
    0001-0010 = reserved
    0011-0111 = IRQ3-IRQ7
    1000 = reserved
    1001-1100 = IRQ9-IRQ12
    1101 = reserved
    1110-1111 = IRQ14-IRQ15
 3-0    map INTC# to IRQ (same values as bits 7-4)
SeeAlso: #P0275,#P0282,#P0284

Bitfields for PicoPower Vesuvius V3-LS PCI INT# configuration register:
Bit(s)    Description    (Table P0284)
 7-4    reserved
 3    interrupt D / mappable IRQ 3 configuration
    0 = INTD#, go through level-to-edge conversion
    1 = MIRQ3, bypass level-to-edge conversion
 2    interrupt C / mappable IRQ 2 configuration
    0 = INTC#, go through level-to-edge conversion
    1 = MIRQ2, bypass level-to-edge conversion
 1    interrupt B / mappable IRQ 1 configuration
    0 = INTB#, go through level-to-edge conversion
    1 = MIRQ1, bypass level-to-edge conversion
 0    interrupt A / mappable IRQ 0 configuration
    0 = INTA#, go through level-to-edge conversion
    1 = MIRQ0, bypass level-to-edge conversion
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS serial IRQ control register:
Bit(s)    Description    (Table P0285)
 7    reserved
 6    serial IRQ mode
    0 = host (primary V3-LS)
    1 = source (secondary V3-LS)
 5-4    reserved
 3-2    start cycle length = 2N+4 clocks
 1    host poll
 0    serial IRQ bus enable
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS serial IRQ control register 2:
Bit(s)    Description    (Table P0286)
 7-4    reserved
 3-0    (revision BB and later) serial IRQ sampling slot length
    1111 = 32 slots
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS power management control register:
Bit(s)    Description    (Table P0287)
 7    secondary activity triggered by IRQ1 (write 0 to clear)
 6    secondary activity triggered by IRQ0 (write 0 to clear)
 5    mask IRQ1 from secondary activity
 4    mask IRQ0 from secondary activity
 3    (revision BB and later) IMR disable
 2    primary activity enables PMI
 1    reserved
 0    burst serial bus enable
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS primary activity IRQ mask register 1:
Bit(s)    Description    (Table P0288)
 7-3    mask IRQ7 - IRQ3 from primary activity
 2    mask NMI from primary activity
 1    mask IRQ1 from primary activity
 0    reserved
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS primary activity IRQ mask register 2:
Bit(s)    Description    (Table P0289)
 7-1    mask IRQ15 - IRQ9 from primary activity
 0    mask IRQ8 from primary activity
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS PMI trigger IRQ mask register 1:
Bit(s)    Description    (Table P0290)
 7-3    mask IRQ7 - IRQ3 from PMI
 2    reserved
 1    mask IRQ1 from PMI
 0    mask DDMA slave lock from PMI
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS PMI trigger IRQ mask register 2:
Bit(s)    Description    (Table P0291)
 7-1    mask IRQ15 - IRQ9 from PMI
 0    mask IRQ8 from PMI
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS PMI trigger source register 1:
Bit(s)    Description    (Table P0292)
 7-3    PMI trigger source IRQ7 - IRQ3 active (write 0 to clear)
 2    reserved
 1    PMI trigger source IRQ1 active (write 0 to clear)
 0    PMI trigger source DDMA slave lock active (write 0 to clear)
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V3-LS PMI trigger source register 2:
Bit(s)    Description    (Table P0293)
 7-1    PMI trigger source IRQ15 - IRQ9 active (write 0 to clear)
 0    PMI trigger source IRQ8 active (write 0 to clear)
SeeAlso: #P0275
----------P00240027--------------------------
PORT 0024-0027 - PicoPower Vesuvius - V1-LS
Note:    software must use 16-bit accesses to these ports; 8-bit accesses will
      be directed to the V3-LS chip in the chipset instead of the V1-LS
SeeAlso: PORT 0024h"V3-LS"

0024w  ?W  V1-LS register index (see #P0294)
0026w  RW  V1-LS register data

(Table P0294)
Values for PicoPower Vesuvius V1-LS register index:
 01xxh    (reset sampling and miscellaneous)
 0100h    revision ID register (see #P0295)
 0101h    V1 power on register (see #P0296)
 0108h    V2 version ID register (see #P0297)
 0109h    V2 configuration register (see #P0298)
 010Ah    V2 miscellaneous status register (see #P0299)
 0110h    programmable region 1 register (see #P0300)
 0111h    programmable region 2 register (see #P0300)
 0112h    programmable region 3 register (see #P0300)
 0113h    programmable region 4 register (see #P0300)
 0114h    programmable region control register (see #P0301)
 0118h    SMM control register (see #P0302)
 0119h    processor control register (see #P0303)
 011Ah    write FIFO control register (see #P0304)
 011Bh    PCI control register (see #P0305)
 011Ch    clock skew adjust register (see #P0306)
 011Dh    bus master and snooping control register (see #P0307)
 011Eh    arbiter control register (see #P0308)
 011Fh    docking control register (see #P0309)
 02xxh    (DRAM registers)
 0200h    shadow RAM read enable control register (see #P0310)
 0201h    shadow RAM write enable control register (see #P0311)
 0202h    bank 0 control register (see #P0312)
 0203h    bank 1 control register (see #P0312)
 0204h    bank 0/1 timing control register (see #P0313)
 0205h    bank 2 control register (see #P0312)
 0206h    bank 3 control register (see #P0312)
 0207h    bank 2/3 timing control register (see #P0313)
 0208h    bank 4 control register (see #P0312)
 0209h    bank 5 control register (see #P0312)
 020Ah    bank 4/5 timing control register (see #P0313)
 020Bh    bank 6 control register (see #P0312)
 020Ch    bank 7 control register (see #P0312)
 020Dh    bank 6/7 timing control register (see #P0313)
 020Eh    DRAM configuration register 1 (see #P0314)
 020Fh    DRAM configuration register 2 (see #P0315)
 0210h    DRAM configuration register 3 (see #P0316)
 0211h    DRAM refresh control register (see #P0317)
 0212h    burst EDO control register (see #P0318)
 03xxh    (Power Management control)
 0300h    clock control register (see #P0319)
 0301h    clock throttling period control register (see #P0320)
 0302h    conserve clock throttling ratio/control register (see #P0321)
 0303h    heat regulator clock throttling ratio/control register (see #P0322)
 0304h    doze/sleep mode clock throttling ratio/control register (see #P0323)
 0310h    wake/SMI source register (see #P0324)
 0311h    power management timer status register (see #P0326)
 0312h    power management pin status register (see #P0327)
 0313h    wake mask control register (see #P0328)
 0314h    activity flag register 1 (see #P0329)
 0315h    activity flag register 2 (see #P0330)
 0316h    I/O trap SMI mask register (see #P0331)
 0317h    external SMI trigger mask register (see #P0332)
 0318h    internal SMI trigger mask register (see #P0333)
 0319h    software SMI trigger mask register (see #P0334)
 031Ah    primary activity option control register (see #P0335)
 031Bh    primary activity mask register 1 (see #P0336)
 031Ch    primary activity mask register 2 (see #P0337)
 031Dh    secondary activity mask register (see #P0338)
 031Eh    RING count control register (see #P0339)
 0320h    programmable range monitor control register 1 (see #P0340)
 0321h    programmable range monitor control register 2 (see #P0341)
 0322h    programmable range monitor 0 address register (see #P0342)
 0323h    programmable range monitor 0 compare register (see #P0343)
 0324h    programmable range monitor 1 address register (see #P0342)
 0325h    programmable range monitor 1 compare register (see #P0343)
 0326h    programmable range monitor 2 address register (see #P0342)
 0327h    programmable range monitor 2 compare register (see #P0343)
 0328h    programmable range monitor 3 address register (see #P0342)
 0329h    programmable range monitor 3 compare register (see #P0343)
 032Ah    programmable range monitor 4 address register (see #P0342)
 032Bh    programmable range monitor 4 compare register (see #P0343)
 032Ch    programmable range monitor 5 address register (see #P0342)
 032Dh    programmable range monitor 5 compare register (see #P0343)
 0330h    power management mode register (see #P0344)
 0331h    on/doze mode power control register (see #P0345)
 0332h    sleep mode power control register (see #P0346)
 0333h    suspend mode power control register (see #P0347)
 0335h    doze mode timer register (see #P0348)
 0336h    sleep mode timer register (see #P0349)
 0337h    suspend mode timer register (see #P0349)
 0338h    secondary activity timer register (see #P0350)
 0339h    power on demand primary activity timer register (see #P0351)
 0340h    general purpose control register (see #P0352)
 0341h    general purpose counter/timer control register (see #P0353)
 0342h    general purpose counter/timer current value register (see #P0354)
 0343h    general purpose counter/timer compare register (see #P0355)
 0344h    device timer 0 time-out register (see #P0356)
 0345h    device timer 1 time-out register (see #P0356)
 0346h    device timer 2 time-out register (see #P0356)
 0347h    device timer 3 time-out register (see #P0356)
 0348h    device timer 4 time-out register (see #P0356)
 0349h    device timer 5 time-out register (see #P0356)
 034Ah    device timer time-out source register 1 (see #P0357)
 034Bh    device timer time-out source register 2 (see #P0358)
 034Ch    device timer time-out source register 3 (see #P0359)
 034Dh    device timer time-out source register 4 (see #P0360)
 0350h    LED indicator control register (see #P0361)
 0351h    leakage control register (see #P0362)
 0352h    pin multiplexing control register (see #P0363)
 0353h    debounce control register (see #P0364)
 0354h    edge detect control register (see #P0365)
 04xxh    (Level-2 Cache)
 0400h    L2 cache configuration register (see #P0366)
 0401h    L2 cache timing register (see #P0367)
 0402h    L2 cache miscellaneous register (see #P0368)
SeeAlso: #P0275

Bitfields for PicoPower Vesuvius V1-LS revision ID register:
Bit(s)    Description    (Table P0295)
 15-4    reserved
 3-0    V1-LS metal-mask version ID
    3h = revision AA
    4h = revision BB
    5h = revision CC
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS V1 power on register:
Bit(s)    Description    (Table P0296)
 15-12    reserved
 11    use internal clocks for simulation
    0 = internal clock speedup disabled
    0 = internal clock speedup enabled
 10    tristate all outputs
    0 = no tristate condition
    1 = tristate condition
 9    reserved
 8    (revision CC and later) snooping scheme
    0 = HOLD/HLDA
    1 = BOFF#/LOCK#
 7    (revision BB and later) PCI power plane voltage
    0 = 3.3 V
    1 = 5 V
 6    (revision BB and later) DRAM power plane voltage
    0 = 3.3 V
    1 = 5 V
 5-3    clock skew adjust
    000 = 0.0 ns
    001 = +0.55 ns
    010 = +1.10 ns
    011 = +1.65 ns
    100 = -2.20 ns
    101 = -1.65 ns
    110 = -1.10 ns
    111 = -0.55 ns
 2-0    miscellaneous configuration
Note:    this register is read-only
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V2-LS V2 version ID register:
Bit(s)    Description    (Table P0297)
 15-12    reserved
 11-8    V2-LS version ID (even)
    3h = revision AA
    4h = revision BB
 7-4    reserved
 3-0    V2-LS version ID (odd) (same values as bits 11-8)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V2-LS V2 configuration register:
Bit(s)    Description    (Table P0298)
 15    V2-LS process monitor enable (odd)
 14-9    reserved
 8    fast PCI master address transfer enable (odd)
 7    V2-LS process monitor enable (even)
 6-1    reserved
 0    fast PCI master address transfer enable (even)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V2-LS V2 miscellaneous status register:
Bit(s)    Description    (Table P0299)
 15-10    reserved
 9    (revision BB & later) PCI power plane voltage (odd)
    0 = 3.3 V
    1 = 5 V
 8    (revision BB & later) DRAM power plane voltage (odd) (as for bit 9)
 7-2    reserved
 1    (revision BB & later) PCI power plane voltage (even) (as for bit 9)
 0    (revision BB & later) DRAM power plane voltage (even) (as for bit 9)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable region register:
Bit(s)    Description    (Table P0300)
 15-3    programmable region starting address bits 27-15 (bits 31-28 = 0)
    (starting address must be a multiple of block size)
 2-0    programmable region block size
    000 = 32 KB
    001 = 64 KB
    010 = 128 KB
    011 = 256 KB
    100 = 512 KB
    101 = 1 MB
    110-111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable region control register:
Bit(s)    Description    (Table P0301)
 15-8    reserved
 7-6    programmable region 4 select
    00 = disable
    01 = write-through
    10 = non-cacheable
    11 = reserved
 5-4    programmable region 3 select (same values as bits 7-6)
 3-2    programmable region 2 select (same values as bits 7-6)
 1-0    programmable region 1 select (same values as bits 7-6)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS SMM control register:
Bit(s)    Description    (Table P0302)
 15    SMM RAM access in normal mode lock (can only be written once)
    0 = bit 14 not locked
    1 = bit 14 locked to disabled
 14    load SMI handler into SMM RAM
    0 = access to SMM RAM during normal cycle disabled
    1 = access to SMM RAM during normal cycle enabled
 13    (revision BB and later) swap SMM D/E mapping
    0 = D0000h-DFFFFh mapped to A0000h-AFFFFh and E0000h-EFFFFh mapped to
      B0000h-BFFFFh
    1 = D0000h-DFFFFh mapped to B0000h-BFFFFh and E0000h-EFFFFh mapped to
      A0000h-AFFFFh
 12    (revision BB and later) swap SMM 2/3 mapping
    0 = 20000h-2FFFFh mapped to A0000h-AFFFFh and 30000h-3FFFFh mapped to
      B0000h-BFFFFh
    1 = 20000h-2FFFFh mapped to B0000h-BFFFFh and 30000h-3FFFFh mapped to
      A0000h-AFFFFh
 11-10    SMM E8000h-EFFFFh select
    00 = normal memory space
    01 = reserved
    10 = SMM space (remap to B8000h-BFFFFh; E8000h-EFFFFh automatically set
      to non-cacheable)
    11 = reserved
 9-8    SMM E0000h-E7FFFh select
    00 = normal memory space
    01 = reserved
    10 = SMM space (remap to B0000h-B7FFFh; E0000h-E7FFFh automatically set
      to non-cacheable)
    11 = reserved
 7-6    SMM D8000h-DFFFFh select
    00 = normal memory space
    01 = reserved
    10 = SMM space (remap to A8000h-AFFFFh; D8000h-DFFFFh automatically set
      to non-cacheable)
    11 = reserved
 5-4    SMM D0000h-D7FFFh select
    00 = normal memory space
    01 = reserved
    10 = SMM space (remap to A0000h-A7FFFh; D0000h-D7FFFh automatically set
      to non-cacheable)
    11 = reserved
 3    reserved
 2    20000h-3FFFFh remap to A0000h-BFFFFh in SMM mode disable
    (can be used only when L1 and L2 are disabled)
 1    SMRAM KEN disable
 0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS processor control register:
Bit(s)    Description    (Table P0303)
 15-10    reserved
 9    FPU error clearing by writing to I/O port F1h disable
 8    FPU error clearing by writing to I/O port F0h disable
 7    reserved
 6    assert INV for write cycle only
 5    write FIFO
    0 = disabled (FIFO forced to one level)
    1 = enabled (FIFO forced to eight level)
 4    combine KEN# and INV pins
 3    linear burst enable
 2    processor pipeline mode enable
 1    L1 write-back enable
 0    CACHE enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS write FIFO control register:
Bit(s)    Description    (Table P0304)
 15-7    reserved
 6-5    PCI write buffering select
    00 = disable
    01 = post-write PCI IO write cycle only
    10 = post-write PCI memory write cycle only
    11 = post-write all PCI write cycles
 4    (revision BB and later) PCI read reordering enable
 3    (revision BB and later) DRAM read reordering enable
 2-0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS PCI control register:
Bit(s)    Description    (Table P0305)
 15-4    reserved
 3    optimized address transfer between V1-LS and V2-LS enable
 2    reserved
 1    PCI master-to-DRAM burst enable
 0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS clock skew adjust register:
Bit(s)    Description    (Table P0306)
 15-3    reserved
 2-0    L2CLK skew adjust
    000 = 0.0 ns
    001 = +0.55 ns
    010 = +1.10 ns
    011 = +1.65 ns
    100 = -2.20 ns
    101 = -1.65 ns
    110 = -1.10 ns
    111 = -0.55 ns
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS bus master and snooping control register:
Bit(s)    Description    (Table P0307)
 15-14    reserved
 13    early DRAM cycle when PCI master accessing DRAM disable
 12-0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS arbiter control register:
Bit(s)    Description    (Table P0308)
 15-7    reserved
 6    REQ2# as FLOAT_REQ# and GNT2# as FLOAT_GNT# enable
 5-4    SIO request/grant source
    00 = none
    01 = BSER interface (normal operation)
    10-11 = reserved
 3    preemptability of PCI request/grant 3 disable
 2    preemptability of PCI request/grant 2 disable
 1    preemptability of PCI request/grant 1 disable
 0    preemptability of PCI request/grant 0 disable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS docking control register:
Bit(s)    Description    (Table P0309)
 15    system docked
 14-4    reserved
 3    DOCK_PCICLK follows state of PCICLK enable
 2    deassert DOCK_PCIRST#
 1    reserved
 0    tristate DOCK_PCIRST# and DOCK_PCICLK in normal operating mode enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS shadow RAM read enable control register:
Bit(s)    Description    (Table P0310)
 15    local memory FC000h-FFFFFh read enable
 14    local memory F8000h-FBFFFh read enable
 13    local memory F4000h-F7FFFh read enable
 12    local memory F0000h-F3FFFh read enable
 11    local memory EC000h-EFFFFh read enable
 10    local memory E8000h-EBFFFh read enable
 9    local memory E4000h-E7FFFh read enable
 8    local memory E0000h-E3FFFh read enable
 7-4    local memory Dx000h-DyFFFh read enable
      (x/y = 0/3 for bit 4, 4/7 for bit 5, etc.)
 3-0    local memory Cx000h-CyFFFh read enable
      (x/y = 0/3 for bit 0, 4/7 for bit 1, etc.)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS shadow RAM write enable control:
Bit(s)    Description    (Table P0311)
 15    local memory FC000h-FFFFFh write enable
 14    local memory F8000h-FBFFFh write enable
 13    local memory F4000h-F7FFFh write enable
 12    local memory F0000h-F3FFFh write enable
 11    local memory EC000h-EFFFFh write enable
 10    local memory E8000h-EBFFFh write enable
 9    local memory E4000h-E7FFFh write enable
 8    local memory E0000h-E3FFFh write enable
 7-4    local memory Dx000h-DyFFFh write enable
      (x/y = 0/3 for bit 4, 4/7 for bit 5, etc.)
 3-0    local memory Cx000h-CyFFFh write enable
      (x/y = 0/3 for bit 0, 4/7 for bit 1, etc.)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS bank control register:
Bit(s)    Description    (Table P0312)
 15    reserved
 14-12    number of column address bits for bank
    000 = 8 bits
    001 = 9 bits
    010 = 10 bits
    011 = 11 bits
    100 = 12 bits
    101-111 = reserved
 11-9    bank DRAM size
    000 = 1 MB
    001 = 2 MB
    010 = 4 MB
    011 = 8 MB
    100 = 16 MB
    101 = 32 MB
    110 = 64 MB
    111 = reserved
 8    reserved
 7-0    bank starting address bits 27-20
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS bank timing control register:
Bit(s)    Description    (Table P0313)
 15-14    reserved
 13-12    bank 0/2/4/6 and 1/3/5/7 CAS write pulse width
    00 = 0.5T (EDO or burst EDO only)
    01 = 1.0T
    10 = 1.5T
    11 = 2.0T
 11-9    bank 0/2/4/6 and 1/3/5/7 CAS read pulse width
    000 = 0.5T (EDO or burst EDO only)
    001 = 1.0T
    ...
    111 = 4.0T
 8    bank 0/2/4/6 and 1/3/5/7 CAS precharge time
    0 = 0.5T
    1 = 1.0T
 7    bank 0/2/4/6 and 1/3/5/7 CAS address hold time (same values as bit 8)
 6-5    bank 0/2/4/6 and 1/3/5/7 RAS address setup time
    00 = 0.0T
    01 = 0.5T
    10 = 1.0T
    11 = 1.5T
 4-3    bank 0/2/4/6 and 1/3/5/7 RAS address hold time = N/2 + 0.5T
 2-0    bank 0/2/4/6 and 1/3/5/7 RAS precharge time    = N/2 + 1.5T
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS DRAM configuration register 1:
Bit(s)    Description    (Table P0314)
 15-9    reserved
 8    fast cacheless read enable (L2 must be disabled and L2 read lead-off
      must be 2T)
 7-6    DRAM auto-detect mode
    00 = normal mode
    01 = setup for auto-detect
    10 = reserved
    11 = auto-detect read mode
 5-3    DRAM inactive time-out
    000 = never
    001 = 8 T
    010 = 32 T
    011 = 128 T
    100 = 512 T
    101-110 = reserved
    111 = immediate
 2-0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS DRAM configuration register 2:
Bit(s)    Description    (Table P0315)
 15-12    reserved
 11    banks 6 and 7
    0 = two 32-bit banks
    1 = one 64-bit bank (bits 7-6 ignored; bank 6 DRAM parameters used;
      programmed bank 6 size doubled)
 10    banks 4 and 5 (same settings as for bit 11)
 9    banks 2 and 3 (same settings as for bit 11)
 8    banks 0 and 1
    0 = two 32-bit banks
    1 = one 64-bit bank (bits 1-0 ignored; bank 0 DRAM parameters used;
      programmed bank 0 size doubled)
 7-0    corresponding bank enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS DRAM configuration register 3:
Bit(s)    Description    (Table P0316)
 15-14    bank 7 DRAM type
    00 = standard
    01 = EDO
    10 = burst EDO
    11 = reserved
 13-12    bank 6 DRAM type (same values as bits 15-14)
 11-10    bank 5 DRAM type (same values as bits 15-14)
 9-8    bank 4 DRAM type (same values as bits 15-14)
 7-6    bank 3 DRAM type (same values as bits 15-14)
 5-4    bank 2 DRAM type (same values as bits 15-14)
 3-2    bank 1 DRAM type (same values as bits 15-14)
 1-0    bank 0 DRAM type (same values as bits 15-14)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS DRAM refresh control register:
Bit(s)    Description    (Table P0317)
 15-14    reserved
 13-12    refresh stagger select
    00 = no staggering
    01 = reserved
    10 = stagger active edge of RAS
    11 = stagger both edges of RAS
 11    reserved
 10    suspend mode self-refresh enable
 9-8    reserved
 7-5    refresh period
    000 = 3.75 µs
    001 = 7.5 µs
    010 = 15 µs
    011 = 30 µs
    100 = 120 µs
    101 = stopped
    110-111 = reserved
 4-3    RAS pulse width for refresh cycles
    00 = 6T
    01 = 5T
    10 = 4T
    11 = 3T
 2-1    RAS precharge time for refresh cycles
    00 = 5T
    01 = 4T
    10 = 3T
    11 = 2T
 0    DRAM refresh scheme
    0 = CAS-before-RAS
    1 = RAS-only
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS burst EDO control register:
Bit(s)    Description    (Table P0318)
 15-4    MA setting during write CAS-before-RAS cycle
 3    trigger write CAS-before-RAS configuration cycle
 2-1    DRAM bank configuration select
    00 = bank 0/1
    01 = bank 2/3
    10 = bank 4/5
    11 = bank 6/7
 0    burst EDO write CAS-before-RAS configuration cycle enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS clock control register:
Bit(s)    Description    (Table P0319)
 15    modular clocking on V2 clock enable
 14-12    reserved
 11    PCI clock control CLKRUN# method enable
 10    reserved
 9    PCI clock goes back to full speed on PCI LOCK# enable
 8    PCI clock goes back to full speed on PCI request/grant enable
 7-6    reserved
 5-4    PCI idle count (PCI clocks)
    00 = immediate
    01 = 8
    10 = 32
    11 = 256
 3-2    reserved
 1-0    PCI clock divisor during idle
    00 = 1
    01 = 2
    10 = 32
    11 = 256
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS clock throttling period control:
Bit(s)    Description    (Table P0320)
 15-3    reserved
 2-0    clock throttling period select (T = CPU bus frequency period)
    000 = 800T
    001 = 1600T
    010 = 3200T
    011 = 6400T
    100 = 12800T
    101 = 25600T
    110 = 102400T
    111 = 409600T
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS conserve clock throttling ratio/control register:
Bit(s)    Description    (Table P0321)
 15-5    reserved
 4    conserve clock throttling enable
 3-0    conserve clock throttling ratio
    0000 = 5% duty cycle
    0001-1001 = 10%-90% duty cycle
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS heat regulator clock throttling:
Bit(s)    Description    (Table P0322)
 15-13    reserved
 12    THERM input enable
 11-4    reserved
 3-0    heat regulator clock throttling ratio
    0000 = 5% duty cycle
    0001-1001 = 10%-90% duty cycle
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS doze/sleep mode clock throttling:
Bit(s)    Description    (Table P0323)
 15-11    reserved
 10-8    STPCLK release latency (PLL stabilization delay)
    000 = 0 s
    001 = 1 µs
    010 = 45 µs
    011 = 1 ms
    100 = 2 ms
    101-111 = reserved
 7-5    sleep mode clock throttling enable
    000 = disable
    001 = enable in ratio set in bits 3-0
    010 = enable LessStop mode (CPU stop grant state)
    011 = enable MoreStop mode (CPU stop clock state)
    100 = enable Deep Sleep mode (MoreStop and high speed oscillator off,
      only 32 kHz running)
 4    doze mode clock throttling enable
 3-0    doze/sleep mode clock throttling ratio
    0000 = 5% duty cycle
    0001-1001 = 10%-90% duty cycle
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS wake/SMI source register:
Bit(s)    Description    (Table P0324)
 15-11    reserved
 10-8    wake-up source
    000 = none
    001 = RING
    010 = SWTCH
    011 = GP timer compare
    100 = WAKE0
    101 = WAKE1
    110 = reserved
    111 = clear wake-up source (write to clear)
 7-5    reserved
 4-0    SMI source (see #00671)
SeeAlso: #P0294

(Table P0325)
Values for PicoPower Vesuvius V1-LS SMI source:
 00h    none
 01h    primary activity
 02h    I/O trap
 03h    device timer time-out
 04h    doze time-out
 05h    sleep time-out
 06h    suspend time-out
 07h    GP timer compare
 08h    SWTCH input toggling
 09h    reserved
 0Ah    WAKE0 input toggling
 0Bh    WAKE1 input toggling
 0Ch    EXTACT0 toggling
 0Dh    reserved
 0Eh    rescheduled SMI
 0Fh    software SMI
 10h    V3-LS INT SMI
 11h-1Eh reserved
 1Fh    clear SMI source (write to clear)
SeeAlso: #P0324

Bitfields for PicoPower Vesuvius V1-LS power management timer status register:
Bit(s)    Description    (Table P0326)
 15-3    reserved
 2    suspend time-out status (write 0 to clear)
 1    sleep time-out status (write 0 to clear)
 0    doze time-out status (write 0 to clear)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS power management pin status register:
Bit(s)    Description    (Table P0327)
 15-6    reserved
 5    SWTCH pin status (read-only)
 4    RING pin status (read-only)
 3    reserved
 2    EXTACT0 pin status (read-only)
 1    WAKE1 pin status (read-only)
 0    WAKE0 pin status (read-only)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS wake mask control register:
Bit(s)    Description    (Table P0328)
 15-5    reserved
 4    mask GP timer compare from resume
 3    mask RING from resume
 2    mask SWTCH from resume
 1    mask WAKE1 from resume
 0    mask WAKE0 from resume
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS activity flag register 1:
Bit(s)    Description    (Table P0329)
 15-10    programmable range 5-0 monitor active (write 0 to clear)
 9    reserved
 8    HOLD active (write 0 to clear)
 7    parallel I/O active (write 0 to clear)
 6    serial I/O 2 active (write 0 to clear)
 5    serial I/O 1 active (write 0 to clear)
 4    keyboard active (write 0 to clear)
 3    floppy disk active (write 0 to clear)
 2    hard disk 2 active (write 0 to clear)
 1    hard disk 1 active (write 0 to clear)
 0    video active (write 0 to clear)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS activity flag register 2:
Bit(s)    Description    (Table P0330)
 15-14    reserved
 13-8    device timer 5-0 time-out (write 0 to clear)
 7    FLOAT_REQ# active (write 0 to clear)
 6    EXTACT0 active (write 0 to clear)
 5    WAKE1 active (write 0 to clear)
 4    WAKE0 active (write 0 to clear)
 3    SWTCH active (write 0 to clear)
 2    RING active (write 0 to clear)
 1    reserved
 0    V3-LS active (write 0 to clear)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS I/O trap SMI mask register:
Bit(s)    Description    (Table P0331)
 15-10    programmable range 5-0 device on
 9-8    reserved
 7    parallel I/O on
 6    serial I/O 2 on
 5    serial I/O 1 on
 4    keyboard on
 3    floppy disk on
 2    hard disk 2 on
 1    hard disk 1 on
 0    video on
Note:    No group mask for I/O trap.
    SMI generated if a bit is 0 and corresponding device is accessed.
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS external SMI trigger mask register:
Bit(s)    Description    (Table P0332)
 15-4    reserved
 3    mask EXTACT0 from SMI
 2    mask SWTCH from SMI
 1    mask WAKE1 from SMI
 0    mask WAKE0 from SMI
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS internal SMI trigger mask register:
Bit(s)    Description    (Table P0333)
 15-10    reserved
 9    mask GP timer compare from SMI
 8    mask suspend time-out from SMI
 7    mask sleep time-out from SMI
 6    mask doze time-out from SMI
 5-0    mask device timer 5-0 time-out from SMI
Note:    Primary activity mask is in register 31Ah bit 1.
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS software SMI trigger mask register:
Bit(s)    Description    (Table P0334)
 15-10    reserved
 9    soft SMI on I/O write to port B0h enable
 8    soft SMI immediate (write 1 to trigger SMI; read value has no meaning)
 7-5    reserved
 4    reschedule SMI prescalar
    0 = 10 ms
    1 = 100 ms
 3-0    reschedule SMI select
    0000 = disable
    0001-1001 = 1-9
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS primary activity option control:
Bit(s)    Description    (Table P0335)
 15-5    reserved
 4    (revision BB and later) mask SMI from primary activity
 3    primary activity on disable
 2    primary activity latching in SMM mode enable
 1    mask primary activity from SMI
 0    primary activity flag enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS primary activity mask register 1:
Bit(s)    Description    (Table P0336)
 15-10    primary activity mask programmable range 5-0 accesses
 9    reserved
 8    primary activity mask HOLD
 7    primary activity mask parallel I/O accesses
 6    primary activity mask serial I/O 2 accesses
 5    primary activity mask serial I/O 1 accesses
 4    primary activity mask keyboard accesses
 3    primary activity mask floppy disk accesses
 2    primary activity mask hard disk 2 accesses
 1    primary activity mask hard disk 1 accesses
 0    primary activity mask video accesses
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS primary activity mask register 2:
Bit(s)    Description    (Table P0337)
 15-13    reserved
 12    primary activity mask FLOAT_REQ#
 11    primary activity mask SWTCH
 10    primary activity mask WAKE1
 9    primary activity mask WAKE0
 8    primary activity mask RING
 7    reserved
 6    primary activity mask EXTACT0
 5-0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS secondary activity mask register:
Bit(s)    Description    (Table P0338)
 15-7    reserved
 6    mask EXTACT0 from secondary activity
 5-2    reserved
 1    mask HOLD from secondary activity
 0    mask SMI from secondary activity
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS RING count control register:
Bit(s)    Description    (Table P0339)
 15-5    reserved
 4    RINGS ten's digit
    0 = 0
    1 = 1
 3-0    RINGS one's digit
    0000 = disabled (ring counter reset, if bit 4 = 0)
    0001-1001 = 1-9
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable range monitor control 1:
Bit(s)    Description    (Table P0340)
 15-14    reserved
 13-8    programmable range monitor 5-0 enable
 7-6    reserved
 5-0    programmable range monitor 5-0 memory or I/O compare
    0 = I/O
    1 = memory
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable range monitor control 2:
Bit(s)    Description    (Table P0341)
 15-14    reserved
 13-8    programmable range monitor 5-0 read enable
 7-6    reserved
 5-0    programmable range monitor 5-0 write enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable range monitor address:
Bit(s)    Description    (Table P0342)
 15-0    programmable range monitor address (I/O address bits 15-0; memory
      address bits 31-16)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS programmable range monitor compare:
Bit(s)    Description    (Table P0343)
 15-0    programmable range monitor compare enable (I/O address bits 15-0;
      memory address bits 31-16)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS power management mode register:
Bit(s)    Description    (Table P0344)
 15-4    reserved
 3    resume
 2-0    system management mode
    000 = on
    001 = doze
    010 = sleep or deep sleep
    011 = suspend
    100-111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS on/doze mode power control register:
Bit(s)    Description    (Table P0345)
 15-6    reserved
 5-0    power control on/doze mode (if on/doze mode active, 1 means
      corresponding power control pin is active)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS sleep mode power control register:
Bit(s)    Description    (Table P0346)
 15-6    reserved
 5-0    power control sleep mode (if sleep mode active, 1 means corresponding
      power control pin is active)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS suspend mode power control register:
Bit(s)    Description    (Table P0347)
 15-6    reserved
 5-0    power control suspend mode (if suspend mode active, 1 means
      corresponding power control pin is active)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS doze mode timer register:
Bit(s)    Description    (Table P0348)
 15-10    reserved
 9    doze mode timer enable
 8    doze mode timer reset by primary activity enable
 7    doze mode timer clock prescalar
    0 = 100 ms
    1 = 1 s
 6-4    doze mode timer ten's digit
    000-111 = 0-7
 3-0    doze mode timer one's digit
    0000-1001 = 0-9
    1010-1111 = reserved
Note:    the timer is disabled when both ten's and one's digits are 0
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS sleep/suspend mode timer register:
Bit(s)    Description    (Table P0349)
 15-10    reserved
 9    sleep/suspend mode timer enable
 8-7    reserved
 6-4    sleep/suspend mode timer ten's digit (0-7)
 3-0    sleep/suspend mode timer one's digit
    0000-1001 = 0-9
    1010-1111 = reserved
Note:    the timer is disabled when both ten's and one's digits are 0
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS secondary activity timer register:
Bit(s)    Description    (Table P0350)
 15-10    reserved
 9    secondary activity timer enable
 8    reset secondary activity on SMI
 7    secondary activity timer clock prescalar
    0 = 100 µs
    1 = 1 ms
 6-4    secondary activity timer ten's digit (0-7)
 3-0    secondary activity timer one's digit
    0000-1001 = 0-9
    1010-1111 = reserved
Note:    the timer is disabled when both ten's and one's digits are 0
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS power on demand primary activity timer:
Bit(s)    Description    (Table P0351)
 15-10    reserved
 9    primary activity timer enable
 8    reserved
 7    primary activity timer clock prescalar
    0 = 100 µs
    1 = 1 ms
 6-4    primary activity timer ten's digit (0-7)
 3-0    primary activity timer one's digit
    0000-1001 = 0-9
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS general purpose control register:
Bit(s)    Description    (Table P0352)
 15-14    reserved
 13-8    general purpose I/O 5-0 direction
    0 = corresponding GPIO pin is an input
    1 = corresponding GPIO pin is an output
 7-6    reserved
 5-0    general purpose I/O 5-0 data
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS general purpose counter/timer control:
Bit(s)    Description    (Table P0353)
 15-8    reserved
 7    general purpose counter/timer enable
 6-5    general purpose counter/timer select
         bit 4 = 0         bit 4 = 1
    00 = 16-bit counter  16-bit counter  (GPIO3 is counter clock)
    01 = 24-bit counter  24-bit counter  (GPIO3 is counter clock)
    10 = 1 second timer  31.25 µs timer
    11 = 1 minute timer  1.875 ms timer
 4    general purpose counter/timer clock select
    0 = 1 Hz
    1 = 32 kHz
 3-0    reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS general purpose counter/timer value:
Bit(s)    Description    (Table P0354)
 15-0    general purpose counter/timer current value (24-bit counter bits
      23-8, otherwise counter/timer bits 15-0; any write resets
      counter/timer)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS general purpose counter/timer compare:
Bit(s)    Description    (Table P0355)
 15-0    general purpose counter/timer compare (24-bit counter compare value
      bits 23-8, otherwise compare value bits 15-0)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS device timer 5-0 time-out register:
Bit(s)    Description    (Table P0356)
 15-6    reserved
 5-4    device timer time-out prescalar
    00 = 1 s
    01 = 10 s
    10 = 1 min.
    11 = 10 min.
 3-0    device timer time-out select
    0000 = disable
    0001-1001 = 1-9
    1010-1111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS device timer time-out source register 1:
Bit(s)    Description    (Table P0357)
 15    reserved
 14-12    keyboard activity device timer select
    000 = none
    001-110 = 0-5
    111 = reserved
 11-9    floppy disk activity device timer select (same values as bits 14-12)
 8-6    hard disk 2 activity device timer select (same values as bits 14-12)
 5-3    hard disk 1 activity device timer select (same values as bits 14-12)
 2-0    video activity device timer select (same values as bits 14-12)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS device timer time-out source register 2:
Bit(s)    Description    (Table P0358)
 15    reserved
 14-12    programmable range 1 activity device timer select
    000 = none
    001-110 = 0-5
    111 = reserved
 11-9    programmable range 0 activity device timer select (same values as
      bits 14-12)
 8-6    parallel port activity device timer select (same values as bits 14-12)
 5-3    serial port 2 activity device timer select (same values as bits 14-12)
 2-0    serial port 1 activity device timer select (same values as bits 14-12)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS device timer time-out source register 3:
Bit(s)    Description    (Table P0359)
 15-12    reserved
 11-9    programmable range 5 activity device timer select
    000 = none
    001-110 = 0-5
    111 = reserved
 8-6    programmable range 4 activity device timer select (same values as
      bits 11-9)
 5-3    programmable range 3 activity device timer select (same values as
      bits 11-9)
 2-0    programmable range 2 activity device timer select (same values as
      bits 11-9)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS device timer time-out source register 4:
Bit(s)    Description    (Table P0360)
 15-3    reserved
 2-0    EXTACT0 activity device timer select
    000 = none
    001-110 = 0-5
    111 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS LED indicator control register:
Bit(s)    Description    (Table P0361)
 15-13    reserved
 12-11    LED1 flash duration
    00 = 256 ms (cannot be set if flash rate is 2 or 4 Hz)
    01 = 128 ms (cannot be set if flash rate is 4 Hz)
    10 = 62.5 ms
    11 = 31.25 ms
 10-9    LED1 flash rate select
    00 = 0.5 Hz
    01 = 1 Hz
    10 = 2 Hz
    11 = 4 Hz
 8    LED1 flasher enable
 7-5    reserved
 4-3    LED0 flash duration (same values as bits 12-11)
 2-1    LED0 flash rate select (same values as bits 10-9)
 0    LED0 flasher enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS leakage control register:
Bit(s)    Description    (Table P0362)
 15-2    reserved
 1    input leakage control during 5 V suspend enable
 0    output leakage control during 5 V suspend enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS pin multiplexing control register:
Bit(s)    Description    (Table P0363)
 15    PC5 function
    0 = PC5
    1 = reserved
 14    PC4 function
    0 = PC4
    1 = LED1 output
 13    PC3 function
    0 = PC3
    1 = LED0 output
 12    reserved
 11-10    GPIO5 function
    00 = GPIO5
    01 = reserved
    10 = THERM input active-high
    11 = THERM input active-low
 9-8    GPIO4 function
    00 = GPIO4
    01 = reserved
    10 = (revision BB and later) SUSPA# input
    11 = reserved
 7-6    GPIO3 function
    00 = GPIO3
    01 = SUPPRESS_RESUME input
    10-11 = reserved
 5-4    GPIO2 function
    00 = GPIO2
    01 = DDMA_RETRY input
    10 = DPSLP_IRQPA input
    11 = reserved
 3-2    GPIO1 function
    00 = GPIO1
    01 = LED1 output
    10 = (revision BB and later) FLOAT_GNT# output
    11 = reserved
 1-0    GPIO0 function
    00 = GPIO0
    01 = LED0 output
    10 = (revision BB and later) FLOAT_REQ# input
    11 = reserved
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS debounce control register:
Bit(s)    Description    (Table P0364)
 15-5    reserved
 4    EXTACT0 debounce select
    0 = 0 s
    1 = 20 ms
 3    RING debounce select (same values as bit 4)
 2    WAKE1 debounce select (same values as bit 4)
 1    WAKE0 debounce select (same values as bit 4)
 0    SWTCH debounce select (same values as bit 4)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS edge detect control register:
Bit(s)    Description    (Table P0365)
 15-10    reserved
 9-8    EXTACT0 edge detect
    00 = reserved
    01 = falling
    10 = rising
    11 = rising and falling
 7-6    RING edge detect
    00 = reserved
    01 = falling
    10 = rising
    11 = reserved
 5-4    WAKE1 edge detect (same values as bits 9-8)
 3-2    WAKE0 edge detect (same values as bits 9-8)
 1-0    SWTCH edge detect (same values as bits 9-8)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS L2 cache configuration register:
Bit(s)    Description    (Table P0366)
 15-10    reserved
 9    TAG initialization enable
 8    NALE mode select
    0 = TAGCS#/NALE# pin is in TAGCS# mode
    1 = TAGCS#/NALE# pin is in NALE# mode
 7    pipelined burst SRAM enable (if bits 5-4 = 01)
 6    reserved
 5-4    L2 cache type
    00 = standard asynchronous
    01 = standard synchronous
    10-11 = reserved
 3-1    L2 cache size select
    000 = 128 KB
    001 = 256 KB
    010 = 512 KB
    011 = 1 MB
    100-111 = reserved
 0    L2 cache enable
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS L2 cache timing register:
Bit(s)    Description    (Table P0367)
 15-8    reserved
 7-6    L2 cache write follow-on
    00 = 1T
    01-11 = reserved
 5-4    L2 cache write leadoff
    00 = 2T
    01 = 3T
    10 = 4T
    11 = reserved
 3-2    L2 cache read follow-on (same values as bits 7-6)
 1-0    L2 cache read leadoff (same values as bits 5-4)
SeeAlso: #P0294

Bitfields for PicoPower Vesuvius V1-LS L2 cache miscellaneous register:
Bit(s)    Description    (Table P0368)
 15-10    reserved
 9-8    (revision BB and later) pipeline on memory read-miss cycle enable
    x0 = disable
    01 = enable (NA generated same time as first BRDY#)
    11 = enable (NA generated as soon as internal read request recognized)
 7    power management on CE# only for 50 MHz operation disable
 6    advanced synchronous power enhanced cache timing enable
 5-2    reserved
 1    invalidation of ROM address disable
 0    dead clock enable
SeeAlso: #P0294
----------P00240029--------------------------
PORT 0024-0029 - HEADLAND HTK340 SHASTA 386/486 CHIPSET

0024  Rw  data port
0028  ?W  index port to chipset registers (see #P0369,#P0370)

(Table P0369)
Values for Headland HT321 register index:
 00h R    chip/revision,read-only
      bit7-4: reserved (=0)
      bit3-0: chip revision, 0=A, 1=B, 3=D
 01h RW system clocking (default=00h)
      bit7-4: reserved (=0)
      bit3-0: ISA speed set
 02h RW system parameters (default=00h) (see #P0371)
 04h RW co-processor (default=00h)
      bit7-3: reserved (=0)
      bit2=1: soft-NPU reset blocked (386 only)
      bit1=1: weitek installed
      bit0=1: 387 installed
 06h RW DMA (default=00h) (see #P0372)
 07h RW EPROM (default=00h) (see #P0373)
 08h RW I/O and memory map holes (default=00h)
      bit7-4: reserved (=0)
      bit3    : 0/1 I/O map hole-A
      bit2    : reserved (=0)
      bit1    : 0/1 memory map hole-B
      bit0    : reserved (=0)
 10h RW hole-A low address (default=00h)
 11h RW hole-A high address (default=00h)
 19h RW mem hole-B start address, lower (default=00h)
 1Ah RW mem hole-B start address, higher (default=00h)
      bit7-6: reserved (=0)
      bit5-0: address of mem hole-B start
 1Ch RW mem hole-B end address, lower (default=00h)
 1Dh RW mem hole-B end address, higher (default=00h)
      bit7-6: reserved (=0)
      bit5-0: address of mem hole-B end
SeeAlso: #P0370

(Table P0370)
Values for Headland HT342 register index:
 20h R    identifier port read
      bit7-4: DRAM controller identifier (0010b)
      bit3-0: revision number (0=A)
 21h R    feature port read    (default=00h)
 24h RW DRAM options port #1 (default=00h)
      bit7    : 0/1 staggered refresh
      bit6    : refresh type
      bit5    : 0/1 DRAM paging
      bit4-2: CAS interleave
      bit1-0: banks
 25h    DRAM options port #2 (default=00h)
      bit7-6: DRAM bank 1 type
      bit5-4: DRAM bank 2 type
      bit3-2: DRAM bank 1?? type
      bit1-0: DRAM bank 0 type
 26h RW DRAM options port #3 (default=FFh) (see #P0374)
 27h RW DRAM options port #4 (default=FFh) (see #P0375)
 28h RW data transfer control port (default=00h)
    doubled indexed registers (28h-2Ah)
      bit7    : initiate transfer
      bit6    : read/write transfer
      bit5-4: reserved
      bit3-0: transfer/destination
 29h RW RAM address register (default=00h)
    doubled indexed registers (28h-2Ah)
      bit7-5: reserved
      bit4-0: RAM address registers contents
 2Ah RW data transfer port   (default=00h)
    doubled indexed registers (28h-2Ah)
      bit7-6: reserved
      bit5    : EMS translation
      bit4    : reserved
      bit3    : 0/1 cacheing
      bit2    : 0/1 write
      bit1    : 0/1 read
      bit0    : 0/1 shadow
 2Bh RW other options          (default=00h) (see #P0376)
 2Dh RW DRAM options port #5 (default=03h)
      bit7-5: reserved
      bit4    : 0/1 10µs RAS timeout
      bit3-2: BUS speed
      bit1-0: BUS recovery for DRAM cycles
           00b=0: 4-1-1-1    10b=0.5
           01b=1: 4-2-2-2    11b=1??
 82h    read transfer
 C2h    write transfer
SeeAlso: #P0369

Bitfields for Headland HT321 register 02h (system parameters):
Bit(s)    Description    (Table P0371)
 7-6    IO recovery time (rev. D+)
 5    parity override
 4-3    cycle-width
 2    0/1 PORT 0092h functionality
 1    IO decode
 0    0/1 posted backplane MEMWN cycles
SeeAlso: #P0369

Bitfields for Headland HT321 register 06h (DMA control):
Bit(s)    Description    (Table P0372)
 7    reserved (=0)
 6    1/0 IOCHRDY during master cycle (rev. C+)
 5    0/1 fast sample DMA
 4-3    DMA waitstate 00b=3 .. 11b=0
 2    0/1 DMA flow-through mode
 1    0/1 extended DMA page register
 0    DMA clock
SeeAlso: #P0369

Bitfields for Headland HT321 register 07h (EPROM control):
Bit(s)    Description    (Table P0373)
 7-6    reserved (=0)
 5    0/1 EADS CACHE invalidation for EPROM writes (rev. D+)
 4    0/1 ROMEN for EPROM writes (rev. C+)
 3    0/1 middle BIOS region of 64KB space below 16MB
 2    ROM-size (0=64KB, 1=128KB)
 1    V-BIOS-add (0=separate, 1=same device)
 0    ROM-access time (0=250ns, 1=125ns)
SeeAlso: #P0369

Bitfields for Headland HT342 register 26h (DRAM CAS control):
Bit(s)    Description    (Table P0374)
 7    CAS hold on RAS (CAS before RAS refresh)
 6    CAS precharge
 5    CAS burst delay
 4    CAS delay (writes)
 3    CAS delay (reads)
 2    CAS active time (writes)
 1-0    CAS active time (reads)
SeeAlso: #P0370,#P0375

Bitfields for Headland HT342 register 27h (DRAM RAS control):
Bit(s)    Description    (Table P0375)
 7    RAS delay
 6-5    RAS active (writes)
 4-2    RAS active (reads)
 1-0    RAS precharge
SeeAlso: #P0370,#P0374

Bitfields for Headland HT342 register 2Bh (other options):
Bit(s)    Description    (Table P0376)
 7    reserved
 6    0/1 middle BIOS
 5    0/1 data pipeline
 4    0/1 data pipeline
 3    IO-decode
 2    reserved
 1    16bit DMA bridge
 0    0/1 write buffering
SeeAlso: #P0370
----------P00260027--------------------------
PORT 0026-0027 - INTEL 82347 POWER MANAGEMENT PERIPHERAL
SeeAlso: PORT 0178h-0179h

0026  -W  index for data port (see #P0377)
0027  RW  power management data

(Table P0377)
Values for Intel 82437 Power Management Peripheral register index:
 C0h    suspend/wakeup status, system state
 C1h    power supply and activity status, general-purpose output/control
 C2h    control bits
 C3h    activity mask
 C4h    NMI mask
 C5h    I/O range for activity monitor
 C6h    power output control bits, ON state
 C7h    power output control bits, Doze state
 C8h    power output control bits, Sleep state
 C9h    power output control bits, Suspend state
 CAh    power control bits polarity control
 CBh    current output bits
 CCh    Doze timeout
 CDh    Sleep timeout
 CEh    Suspend timeout
 CFh    LCD display power timeout
 D0h    EL display power timeout
----------P00260027--------------------------
PORT 0026-0027 - Chips&Technologies CS4021 - "SuperState V" ALTERNATE CONFIG
Desc:    alternate copy of the configuration register access at PORT 0022h/0023h
      which may be used by system software in "SuperState V" to configure
      the chipset without disturbing accesses to PORT 0022h by user code
Notes:    SuperState V is an early version of system management mode
    these ports can only be accessed while the system is in SuperState V;
      similarly, some configuration registers are read-only via PORT 0022h
      and others can optionally be made read-only
SeeAlso: PORT 0022h"Chips&Technologies"
!!!chips\cs4021.pdf p.149

0026  -W  configuration register index
0027  RW  configuration register data
----------P0028002A--------------------------
PORT 0028-002A - 80486 "Deep Green" motherboard - ???

0028  ?W  index for data port
002A  RW  ??? data port

Note:    in order to access to the registers available through PORT 002A,
      an unlocking sequence must be written via PORT 0028:    write
      A0h, 05h, index to PORT 0028, then read/write PORT 002A, then
      write A5h to PORT 0028
----------P002E002F--------------------------
PORT 002E-002F - DELL ENHANCED PARALLEL PORT
SeeAlso: PORT 015Ch,PORT 026Eh,PORT 0398h

002E  -W  index for data port (see #P0378)
002F  RW  EPP command data

(Table P0378)
Values for Dell Enhanced Parallel Port register index:
 00h    bit 0: ???
 02h    bit 7: port in bidirectional mode
 04h    bits 0 and 2: ECP/EPP mode control
----------P002E002F--------------------------
PORT 002E-002F - Intel "Nonolet" Motherboard - POWER MANAGEMENT

002E  ?W  index for data port
002F  ?W  data port

code sequence posted in fido7.nice.sources by Konstantin Mohorea:
     out 2Eh,0Ch
     out 2Fh,75h
     out 2Eh,11h
     out 2Fh,00h
     out 2Eh,0Dh
     out 2Fh,A0h
----------P002E002F--------------------------
PORT 002E-002F - NS PC87306 SuperI/O - CONFIGURATION REGISTERS
InstallCheck: after a hardware reset, the first read of the index port returns
      88h, and a second consecutive read always returns 00h (while
      read-after-write always returns the written value)
Range:    PORT 002Eh, PORT 015Ch, PORT 026Eh, or PORT 0398h, depending on
      external strapping
Note:    to set a register, the data port must be written twice in a row; the
      value is latched on the second write

002E  RW  configuration register index
002F  RW  configuration register data
----------P0038003F--------------------------
PORT 0038-003F - PC radio by CoZet Info Systems
Notes:    The I/O address range is dipswitch selectable from:
       038-03F and 0B0-0BF
       078-07F and 0F0-0FF
       138-13F and 1B0-1BF
       178-17F and 1F0-1FF
       238-23F and 2B0-2BF
       278-27F and 2F0-2FF
       338-33F and 3B0-3BF
       378-37F and 3F0-3FF
    All of these addresses show a readout of FF in initial state.
    Once started, all of the addresses show     FB, whatever might happen.
----------P0040005F--------------------------
PORT 0040-005F - PIT - PROGRAMMABLE INTERVAL TIMER (8253, 8254)
Notes:    XT & AT use ports 40h-43h; PS/2 uses ports 40h, 42h-44h, and 47h
    the counter chip is driven with a 1.193 MHz clock (1/4 of the
    original PC's 4.77 MHz CPU clock)
SeeAlso: PORT 0044h,PORT 0048h

0040  RW  PIT  counter 0, counter divisor          (XT, AT, PS/2)
    Used to keep the system time; the default divisor of (1)0000h
    produces the 18.2Hz clock tick.
0041  RW  PIT  counter 1, RAM refresh counter    (XT, AT)
    don't set below 3 on PCs (default 12h), and don't mess with this
    counter at all unless you really know what you're doing....
0042  RW  PIT  counter 2, cassette & speaker    (XT, AT, PS/2)
    During normal operation mode (8253) 40h-42h set the counter values on
    write and get the current counter value on read. In 16bit modes two
    consequtive writes/reads must be issued, first with the low byte,
    followed by the high byte. In 8254 read back modes, all selected
    counters and status are latched and must be read out completely
    before normal operation is valid again.     Each counter switches back
    to normal operation after read out.  In 'get status and counter'
    mode the first byte read is the status, followed by one or two
    counter values. (see #P0379)  Note that 16-bit reads performed
    without using the "latch" command will get the current high/low
    portion of the counter at the instant of the port read, so it is
    possible for the low part of the counter to wrap around before the
    high part gets read, resulting in a significant measurement error
0043  RW  PIT  mode port, control word register for counters 0-2 (see #P0380)
    Once a control word has been written (43h), it must be followed
    immediately by performing the corresponding action to the counter
    registers (40h-42h), else the system may hang!!

Bitfields for 8254 PIT counter status byte:
Bit(s)    Description    (Table P0379)
 7    PIN status of OUTx Pins (1=high, 0=low)
 6    counter start value loaded
    =0: yes, so counter latch is valid to be read
    =1: no, wait for counter latch to be set (may last a while)
5-0    counter mode, same as bit5-0 at 43h
SeeAlso: #P0380

Bitfields for 8253/8254 PIT mode control word:
Bit(s)    Description    (Table P0380)
 7-6    counter select
    00  counter 0 select
    01  counter 1 select      (not PS/2)
    10  counter 2 select
    11  (8253) reserved
        (8254) read back counter (see #P0379)
---if counter select---
 5-4    counter access
    00  counter latch command
        BUG:    Intel Neptune/Mercury/Aries Chipset 8237IB (SIO) needs
              a short delay after issuing this command, else the
              latched MSB may be outdated with respect to the LSB,
              resulting in large measuring errors.
            Workaround: Check for this condition by comparing
              results with last results and don't use erroneous
              results.
    01  read/write counter bits 0-7 only
    10  read/write counter bits 8-15 only
    11  read/write counter bits 0-7 first, then 8-15
 3-1    counter mode
    000 mode 0 select - zero detection interrupt
    001 mode 1 select - programmable one shot
    x10 mode 2 select - rate generator
    x11 mode 3 select - square wave generator
        counts down twice by two at a time; latch status and check
          value of OUT pin to determine which half-cycle is active
        divisor factor 3 not allowed!
    100 mode 4 select - software triggered strobe
    101 mode 5 select - hardware triggered strobe
 0    counting style
    0  binary counter 16 bits
    1  BCD counter (4 decades)
---if read back---
 5-4    what to read
    00 counter status, then value
    01 counter value
    10 counter status
    11 reserved
 3    select counter 2
 2    select counter 1
 1    select counter 0
 0    reserved (0)
Note:    after issuing a read back 'get status' command, any new read back
      command is ignored until the status is read from all selected
      counters.
----------P00440047--------------------------
PORT 0044-0047 - Microchannel - PROGRAMMABLE INTERVAL TIMER 2
SeeAlso: PORT 0040h,PORT 0048h

0044  RW  PIT  counter 3 (PS/2)
        used as fail-safe timer. generates an NMI on time out.
        for user generated NMI see at 0462.
0047  -W  PIT  control word register counter 3 (PS/2, EISA)
    bit 7-6 = 00  counter 3 select
        = 01  reserved
        = 10  reserved
        = 11  reserved
    bit 5-4 = 00  counter latch command counter 3
        = 01  read/write counter bits 0-7 only
        = 1x  reserved
    bit 3-0 = 00
----------P0048004B--------------------------
PORT 0048-004B - EISA - PROGRAMMABLE INTERVAL TIMER 2
Note:    this second timer is also supported by many Intel chipsets
SeeAlso: PORT 0040h,PORT 0044h

0048  RW  EISA PIT2 counter 3 (Watchdog Timer)
0049  ??  EISA 8254 timer 2, not used (counter 4)
004A  RW  EISA PIT2 counter 5 (CPU speed control)
004B  -W  EISA PIT2 control word
--------K-P0060006F--------------------------
PORT 0060-006F - KEYBOARD CONTROLLER 804x (8041, 8042) (or PPI (8255) on PC,XT)
Note:    XT uses ports 60h-63h, AT uses ports 60h-64h

0060  RW  KB controller data port or keyboard input buffer (ISA, EISA)
        should only be read from after status port bit0 = 1
        should only be written to if status port bit1 = 0
0060  R-  KeyBoard or KB controller data output buffer (via PPI on XT)
        PC: input from port A of 8255, if bit7 in 61h set (see #P0396)
        get scancodes, special codes (in PC: with bit7 in 61h cleared)
          (see #P0390)

0061  R-  KB controller port B control register (ISA, EISA)
        system control port for compatibility with 8255 (see #P0393)
0061  -W  KB controller port B (ISA, EISA)   (PS/2 port A is at 0092)
        system control port for compatibility with 8255 (see #P0392)
0061  -W  PPI Programmable Peripheral Interface 8255 (XT only)
        system control port (see #P0394)
0062  RW  PPI (XT only) data port C (see #P0395)
0063  RW  PPI (XT only) command mode register (see #P0397)

0064  R-  keyboard controller read status (see #P0398,#P0399,#P0400)
0064  -W  keyboard controller input buffer (ISA, EISA) (see #P0401)

0064  -W  (Amstrad/Schneider PC1512) set 'DIP switch S1' setting
      stored in CMOS RAM that PPI should report for compatibility
0065  -W  (Amstrad/Schneider PC1512) set 'DIP switch S2' RAM size setting
      stored in CMOS RAM, that PPI port C (PORT 0064h) should report for
      compatibility

0065  R-  communications port (Olivetti M24)

Bitfields for AT keyboard controller input port:
Bit(s)    Description    (Table P0381)
 7    keyboard enabled
 6    =0  CGA, else MDA
 5    =0  manufacturing jumper installed
 4    =0  system RAM 512K, else 640K
 3-0    reserved
SeeAlso: #P0382,#P0384

Bitfields for AT keyboard controller input port (Compaq):
Bit(s)    Description    (Table P0382)
 7    security lock is unlocked
 6    =0  Compaq dual-scan display, 1=non-Compaq display
 5    system board dip switch 5 is OFF
 4    =0  auto speed selected, 1=high speed selected
 3    =0  slow (4MHz), 1 = fast (8MHz)
 2    no math coprocessor installed
 1-0    reserved
SeeAlso: #P0383

Bitfields for AT keyboard controller output port:
Bit(s)    Description    (Table P0383)
 7    keyboard data output
 6    keyboard clock output
 5    input buffer NOT full
 4    output buffer NOT empty
 3    reserved (see note)
 2    reserved (see note)
 1    gate A20
 0    system reset
Note:    bits 2 and 3 are the turbo speed switch or password lock on
      Award/AMI/Phoenix BIOSes.  These bits make use of nonstandard
      keyboard controller BIOS functionality to manipulate
        pin 23 (8041 port 22) as turbo switch for AWARD
        pin 35 (8041 port 15) as turbo switch/pw lock for Phoenix
SeeAlso: #P0381,#P0384

Bitfields for HP Vectra keyboard controller output port:
Bit(s)    Description    (Table P0384)
 7-5    reserved
 4    output buffer full (OBF) interrupt
 3    HP SVC interrupt
 2    HP-HIL controller AutoPoll
 1    A20 gate
 0    system reset
SeeAlso: #P0383,#P0385

Bitfields for HP Vectra command byte:
Bit(s)    Description    (Table P0385)
 7    reserved (0)
 6    scancode conversion mode (1 = PC/XT, 0 = PC/AT)
 5    unused
 4    disable keyboard (unless bit 3 set)
 3    override keyboard disable
 2    System Flag (may be read from PORT 0060h)
 1    reserved
 0    OBF interrupt enable
SeeAlso: #P0384

(Table P0386)
Values for keyboard commands (data also goes to PORT 0060h):
Value    Count    Description
 EDh    double    set/reset mode indicators Caps Num Scrl
        bit 2 = CapsLk, bit 1 = NumLk, bit 0 = ScrlLk
        all other bits must be zero.
 EEh    sngl    diagnostic echo. returns EEh.
 EFh    sngl    NOP (No OPeration). reserved for future use
 EF+26h    double    [Cherry MF2 G80-1501HAD] read 256 bytes of chipcard data
        keyboard must be disabled before this and has to
        be enabled after finished.
 F0h    double    get/set scan code set
        00h get current set
        01h scancode set 1 (PCs and PS/2 mod 30, except Type 2 ctrlr)
        02h scancode set 2 (ATs, PS/2, default)
        03h scancode set 3
 F2h    sngl    read keyboard ID (read two ID bytes)
        AT keyboards returns FA (ACK)
        MF2 returns AB 41 (translation) or
                AB 83 (pass through)
 F3h    double    set typematic rate/delay
        format of the second byte:
        bit7=0 : reserved
        bit6-5 : typemativ delay
             00b=250ms     10b= 750ms
             01b=500ms     11b=1000ms
        bit4-0 : typematic rate (see #P0391)
 F4h    sngl    enable keyboard
 F5h    sngl    disable keyboard. set default parameters (no keyboard scanning)
 F6h    sngl    set default parameters
 F7h    sngl    [MCA] set all keys to typematic (scancode set 3)
 F8h    sngl    [MCA] set all keys to make/release
 F9h    sngl    [MCA] set all keys to make only
 FAh    sngl    [MCA] set all keys to typematic/make/release
 FBh    sngl    [MCA] set al keys to typematic
 FCh    double    [MCA] set specific key to make/release
 FDh    double    [MCA] set specific key to make only
 FEh    sngl    resend last scancode
 FFh    sngl    perform internal power-on reset function
Note:    each command is acknowledged by FAh (ACK), if not mentioned otherwise.
      See PORT 0060h-R for details.
SeeAlso: #P0387

(Table P0387)
Values for Mouse functions (for PS/2-like pointing devices):
Value    Count    Description
 E6h    sngl    set mouse scaling to 1:1
 E7h    sngl    set mouse scaling to 2:1
 E8h    double    set mouse resolution
        (00h=1/mm, 01h=2/mm, 02h=4/mm, 03h=8/mm)
 E9h    sngl    get mouse information
        read two status bytes:
          byte 0: flags (see #P0388)
          byte 1: resolution
 EAh    sngl    set mouse to stream mode (mouse sends data on any changes)
 EBh    sngl    get mouse data (from mouse to controller) (see #P0389)
        on reading, each data packet consists of 8 bytes:
 ECh    sngl    reset mouse wrap mode (to normal mode)
 EEh    sngl    set wrap mode
 F0h    sngl    set remote mode (instead of stream mode), mouse sends data
          only on issueing command EBh.
 F2h    sngl    read mouse ID (read one, two?? ID bytes)
        00h=mouse
 F3h    double    set mouse sample rate in reports per second
        0Ah=10/s       50h= 80/s
        14h=20/s       64h=100/s
        28h=40/s       C8h=200/s
        3Ch=60/s
 F4h    sngl    enable mouse (in stream mode)
 F5h    sngl    disable mouse (in steam mode), set default parameters
 F6h    sngl    reset to defaults: 100/s, scaling 1:1, stream-mode, 4/mm,
          disabled
 FEh    sngl    resend last mouse data (8 bytes, see EBh)
 FFh    sngl    reset mouse
Notes:     must issue command D4h to PORT 0064h first to access mouse functions
     all commands except ECh and FFh are acknowledged by FAh (ACK) or
       FEh (Resend); get mouse ID (F2h) returns mouse ID.
SeeAlso: #P0386

Bitfields for mouse status byte 0:
Bit(s)    Description    (Table P0388)
 7    unused
 6    remote rather than stream mode
 5    mouse enabled
 4    scaling set to 2:1
 3    unused
 2    left button pressed
 1    unused
 0    right button pressed
SeeAlso: #P0387,#P0389

Format of mouse data packet:
Offset    Size    Description    (Table P0389)
 00h    BYTE    status
        bit7    : y-data overrun
        bit6    : x-data overrun
        bit5    : y-data negative
        bit4    : x-data negative
        bit3-2=0: reserved
        bit1    : right button pressed
        bit0    : left button pressed
 01h    BYTE    reserved
 02h    BYTE    x-data
 03h    BYTE    reserved
 04h    BYTE    y-data
 05h    BYTE    reserved
 06h    BYTE    z-data (0)
 07h    BYTE    reserved
SeeAlso: #P0387,#P0388

(Table P0390)
Values for keyboard special codes:
 00h    (MF2 in codeset2&3 or AT keyboards) keydetection/overrun error
 00h    (mouse) ID
 AAh    BAT completion code (sent after errorfree Basic Assurance Test)
 ABh    first byte of general MF2 keyboard ID
 EEh    Echo command return
 FAh    Acknowledge (all general commands except Resend and Echo)
 FAh    (mouse) Acknowledge (all commands except commands ECh,F2h,FFh)
 FCh    (MF2) BAT Failure Code (error in second half of the power on self test)
 FDh    (AT-keyboard) BAT Failure Code (error in the second half of the
      power-on self test)
 FEh    Resend: CPU to controller should resend last keyboard-command
 FEh    (mouse) CPU to controller should resend last mouse-command
 FFh    (MF2 in codeset1) keydetection/overrun error
Note:    keyboard stops scanning and waits for next command after returning
      code FCh or FDh
SeeAlso: PORT 0060h-R

(Table P0391)
Values for keyboard typematic rate:
 00000b=30.0   10000b=7.5
 00001b=26.7   10001b=6.7
 00010b=24.0   10010b=6.0
 00011b=21.8   10011b=5.5
 00100b=20.0   10100b=5.0
 00101b=18.5   10101b=4.6
 00110b=17.1   10110b=4.3
 00111b=16.0   10111b=4.0
 01000b=15.0   11000b=3.7
 01001b=13.3   11001b=3.3
 01010b=12.0   11010b=3.0
 01011b=10.9   11011b=2.7
 01100b=10.0   11100b=2.5
 01101b= 9.2   11101b=2.3
 01110b= 8.5   11110b=2.1
 01111b= 8.0   11111b=2.0
SeeAlso: #P0386

Bitfields for KB controller port B (system control port) [output]:
Bit(s)    Description    (Table P0392)
 7    pulse to 1 for IRQ1 reset (PC,XT)
 6-4    reserved
 3    I/O channel parity check disable
 2    RAM parity check disable
 1    speaker data enable
 0    timer 2 gate to speaker enable
SeeAlso: PORT 0061h-W,#P0393

Bitfields for KB ctrller port B control register (system control port) [input]:
Bit(s)    Description    (Table P0393)
 7    RAM parity error occurred
 6    I/O channel parity error occurred
 5    mirrors timer 2 output condition
 4    toggles with each refresh request
 3    NMI I/O channel check status
 2    NMI parity check status
 1    speaker data status
 0    timer 2 clock gate to speaker status
Note:    also supported by OPTi 82C392
SeeAlso: PORT 0061h-R,#P0392

Bitfields for Progr. Peripheral Interface (8255) system control port [output]:
Bit(s)    Description    (Table P0394)
 7    clear keyboard (only pulse, normally kept at 0)
 6    =0  hold keyboard clock low
 5    NMI I/O parity check disable
 4    NMI RAM parity check disable
 3    =0 read low nybble of switches S2
    =1 read high nybble of switches S2
 2    reserved, often used as turbo switch
    original PC: cassette motor off
 1    speaker data enable
 0    timer 2 gate to speaker enable
Note:    bits 2 and 3 are sometimes used as turbo switch
SeeAlso: PORT 0061h-W,#P00051,#P0395,#P0396,#P0397

Bitfields for PPI (XT only) data port C:
Bit(s)    Description    (Table P0395)
 7    RAM parity error occurred
 6    I/O channel parity error occurred
 5    timer 2 channel out
 4    reserved
    original PC: cassette data input
---
 3    system board RAM size type 1
 2    system board RAM size type 2
 1    coprocessor installed
 0    loop in POST
---
 3-0    DIL switch S2 high/low nybble (depending on PORT 0061h bit 3)
SeeAlso: PORT 0062h-RW,#P0394,#P0396,#P0397

Bitfields for PPI (PC,XT only) equipment switches [input]:
Bit(s)    Description    (Table P0396)
 7-6    number of disk drives
    00  1 diskette drive
    01  2 diskette drives
    10  3 diskette drives
    11  4 diskette drives
 5-4    initial video
    00  reserved (video adapter has on-board BIOS)
    01  40*25 color (mono mode)
    10  80*25 color (mono mode)
    11  MDA 80*25
 3-2    memory size (using 256K chips)
    00  256K
    01  512K
    10  576K
    11  640K
 3-2    memory size (using 64K chips)
    00  64K
    01  128K
    10  192K
    11  256K
 3-2    memory size (original PC)
    00  16K
    01  32K
    10  48K
    11  64K
 1-0    reserved
 1    NPU (math coprocessor) present
 0    boot from floppy
SeeAlso: #P0395,#P0397,PORT 0060h-R

Bitfields for PPI (8255) command mode register:
Bit(s)    Description    (Table P0397)
 7    activation function (0 = bit set/reset, 1 = mode set function)
 6,5    port A mode: 00 = mode0, 01 = mode1, 1x = mode2
 4    port A direction: 0 = output, 1 = input
 3    port C bits 7-4 direction: 0 = output, 1 = input
 2    port B mode: 0 = mode0, 1 = mode1
 1    port B direction: 0 = output, 1 = input
 0    port C bits 3-0 direction: 0 = output, 1 = input
Note:    Attention: Never write anything other than 99h to this port
      (better: never write anything to this port, only during BIOS
      init), as other values may connect multiple output drivers
      and will cause hardware damage in PC/XTs!  By setting command
      word to 99h, PPI will be set in input/output modes as it is
      necessary to support the commonly known IO-ports 60, 61, 62
      as desired.
SeeAlso: #P0394,#P0395,#P0396

Bitfields for keyboard controller read status (ISA, EISA):
Bit(s)    Description    (Table P0398)
 7    parity error on transmission from keyboard
 6    receive timeout
 5    transmit timeout
 4    keyboard interface inhibited by keyboard lock
 3    =1 data written to input register is command (PORT 0064h)
    =0 data written to input register is data (PORT 0060h)
 2    system flag status: 0=power up or reset     1=selftest OK
 1    input buffer full (input 60/64 has data for 8042)
    no write access allowed until bit clears
 0    output buffer full (output 60 has data for system)
    bit is cleared after read access
SeeAlso: PORT 0064h-R,#P0399,#P0400,#P0401

Bitfields for keyboard controller read status (MCA):
Bit(s)    Description    (Table P0399)
 7    parity error on transmission from keyboard
 6    general timeout
 5    mouse output buffer full
 4    keyboard interface inhibited by keyboard lock
 3    =1 data written to input register is command (PORT 0064h)
    =0 data written to input register is data (PORT 0060h)
 2    system flag status: 0=power up or reset     1=selftest OK
 1    input buffer full (60/64 has data for 804x)
    no write access allowed until bit clears
 0    output buffer full (output 60 has data for system)
    bit is cleared after read access
SeeAlso: #P0398,#P0400,#P0401

Bitfields for keyboard controller read status (Compaq):
Bit(s)    Description    (Table P0400)
 7    parity error detected (11-bit format only). If an
      error is detected, a Resend command is sent to the
      keyboard once only, as an attempt to recover.
 6    receive timeout. transmission didn't finish in 2mS.
 5    transmission timeout error
    bit 5,6,7  cause
        1 0 0  No clock
        1 1 0  Clock OK, no response
        1 0 1  Clock OK, parity error
 4    =0 security lock engaged
 3    =1 data in OUTPUT register is command
    =0 data in OUTPUT register is data
 2    system flag status: 0=power up or reset     1=soft reset
 1    input buffer full (60/64 has data for 804x)
    no write access allowed until bit clears
 0    output buffer full (PORT 0060h has data for system)
    bit is cleared after read access
SeeAlso: #P0398,#P0399,#P0401

(Table P0401)
Values for keyboard controller commands (data goes to PORT 0060h):
Value        Description
 20h    read    read byte zero of internal RAM, this is the last KB command
          sent to the 8041/8042
    Compaq    put current command byte on PORT 0060h (see #P0403,#P0404)
 21-3F    read    reads the byte specified in the lower 5 bits of the command
          in the 804x's internal RAM (see #P0407)
 60-7F    double    writes the data byte to the address specified in the 5 lower
          bits of the command
 60h    Compaq    Load new command (60 to [64], command to [60]) (see #P0404)
        (also general AT-class machines)
 A0h    AMI    get ASCIZ copyright message on PORT 0060h
 A1h    AMI    get controller version byte on PORT 0060h
 A1h    Compaq    unknown speedfunction ??
 A1h    C&T    CHIPS extensions (see #P0402)
 A2h    Compaq    unknown speedfunction ??
 A2h    AMI    set keyboard controller pins 22 and 23 low
 A2h    C&T    turn on turbo LED
 A3h    Compaq    Enable system speed control
 A3h    AMI    set keyboard controller pins 22 and 23 high
 A3h    C&T    turn off turbo LED
 A4h    MCA    check if password installed
        returns PORT 0060h code F1h if no password, FAh if installed
 A4h    Compaq    Toggle speed
 A4h    AMI    set internal system speed flag to low
 A5h    MCA    load password
        write successive scan codes to PORT 0060h, terminate with 00h
 A5h    AMI    set internal system speed flag to high
 A5h    Compaq    Special read. the 8042 places the real values of port 2
          except for bits 4 and 5 wich are given a new definition in
          the output buffer. No output buffer full is generated.
            if bit 5 = 0, a 9-bit keyboard is in use
            if bit 5 = 1, an 11-bit keyboard is in use
            if bit 4 = 0, output-buff-full interrupt disabled
            if bit 4 = 1, output-buffer-full interrupt enabled
 A6h    MCA    check password
 A6h    AMI    get internal system speed flag on PORT 0060h
 A6h    Compaq    unknown speedfunction ??
 A7h    MCA    disable mouse port
 A7h    AMI    set internal flag indicating bad write cache
 A8h    MCA    enable mouse port
 A8h    AMI    set internal flag indicating good write cache
 A9h    MCA    test mouse port, return test result on PORT 0060h (see #P0406)
 A9h    AMI    get internal flag indicating cache OK to PORT 0060h
 AAh    sngl    initiate self-test. will return 55h to data port if self-test
          successful, FCh if failed
 AAh    Compaq    initializes ports 1 and 2, disables the keyboard and clears
          the buffer pointers. It then places 55h in the output buffer.
 ABh    sngl    initiate interface test, return result value on PORT 0060h
          (see #P0406)
 ACh    read    diagnostic dump. the contents of the 804x RAM, output port,
          input port, status word are sent to PORT 0060h in scan-code
          format; Chips&Technologies 8042's append "CHIPS Vxxx" where
          "xxx" is the controller version number
 ADh    sngl    disable keyboard (sets bit 4 of commmand byte)
 ADh    Vectra    HP Vectra diagnostic dump
 AEh    sngl    enable keyboard     (resets bit 4 of commmand byte)
 AFh    AWARD    Enhanced Command: read keyboard version
 AFh    AMI    set extended controller RAM
        write address to PORT 0060h, wait for controller ready, then
          write value to PORT 0060h
 B1h    AMI    set keyboard controller P11 line low
 B2h    AMI    set keyboard controller P12 line low
 B3h    AMI    set keyboard controller P13 line low
 B4h    AMI    set keyboard controller P22 line low
 B5h    AMI    set keyboard controller P23 line low
 B8h    AMI    set keyboard controller P10 line high
 B9h    AMI    set keyboard controller P11 line high
 BAh    AMI    set keyboard controller P12 line high
 BBh    AMI    set keyboard controller P13 line high
 BCh    AMI    set keyboard controller P22 line high
 BDh    AMI    set keyboard controller P23 line high
 C0h    read    read input port and place on PORT 0060h
        bit 7    keyboard NOT locked
        bit 6    =0 first video is CGA
            =1 first video is MDA
        bit 5    =0 factory testmode
            =1 normal
        bit 4    =0 256KB RAM, 1=512KB
        bit 5,3-0 are used in Intel chipset 386sx machines with
            AMI/Phoenix BIOSes for BIOS specific hardware settings
        bit 2    (MCA) no keyboard power
        bit 1    (MCA) current mouse serial data input state
        bit 0    (MCA) current keyboard serial input state
 C0h    Compaq    places status of input port in output buffer.  Use this
          command only when the output buffer is empty
 C1h    MCA    Enhanced Command: poll input port Low nibble, continuously
          place in PORT 0064h bits 7-4 until next command
 C2h    MCA    Enhanced Command: poll input port High nibble, continuously
          place in PORT 0064h bits 7-4 until next command
 C8h    AMI    unblock keyboard controller lines P22 and P23
 C9h    AMI    block keyboard controller lines P22 and P23
 CAh    AMI    read keyboard mode, return in 0060 bit 0
          (bit clear if ISA mode, set if PS/2 mode)
 CBh    AMI    set keyboard mode (write back mode byte returned by CAh,
          modifying only bit 0)
 CCh    AMI    ??? (used by AMI BIOS v1.00.12.AX1T APM code)
 D0h    read    read output port and place on PORT 0060h (see #P0405)
 D0h    Compaq    places byte in output port in output buffer. Use this command
          only when the output buffer is empty
 D1h    double    write output port.  The next byte written to PORT 0060h will
          be written to the 804x output port; the original IBM AT and
          many compatibles such as the OPTi 82C392 use bit 1 of the
          output port to control the A20 gate.
        Important: bit 0 (system reset) should always be set here, as
              the system may hang constantly; use pulse output port
              (FEh) instead.
 D1h    Compaq    the system speed bits are not set by this command use
          commands A1-A6 (!) for speed functions.
 D2h    MCA    Enhanced Command: write keyboard output buffer
 D3h    MCA    Enhanced Command: write pointing device out.buf.
 D4h    MCA    write to mouse/pointing device instead of to keyboard; this
          controller command must precede every PORT 0060h command
          directed to the mouse, otherwise it will be sent to the
          keyboard
 D4h    AWARD    Enhanced Command: write to auxiliary device
 DDh    sngl    disable address line A20 (HP Vectra only???)
        default in Real Mode
 DFh    sngl    enable address line A20 (HP Vectra only???)
 E0h    read    read test inputs, and place in PORT 0060h
        bit0 = kbd clock, bit1 = kbd data
 Exxx    AWARD    Enhanced Command: active output port
 E5h    GoldStar set turbo LED color to yellow (turbo off)
 E7h    GoldStar set turbo LED color to yellow (turbo off)
 E8h    GoldStar set turbo LED color to green (turbo on)
 EAh    GoldStar set turbo LED color to green (turbo on)
 EDh    double    this is a two part command to control the state of the
          NumLock, CpasLock and ScrollLock LEDs
        The second byte contains the state to set LEDs.
            bit 7-3    reserved. should be set to 0.
            bit 2 = 0    Caps Lock LED off
            bit 1 = 0    Num Lock LED off
            bit 0 = 0    Scroll Lock LED off
 F0-FF    sngl    pulse output port low for 6 microseconds.
        bits 0-3 contain the mask for the bits to be pulsed.  A bit is
          pulsed if its mask bit is zero
        bit0=system reset. Don't set to zero. Pulse only!
Note:     keyboard controllers are widely different from each other.  You
       cannot generally exchange them between different machines.
     (Award) Derived from Award's Enhanced KB controller advertising sheet.
     (Compaq) Derived from the Compaq Deskpro 386 Tech. Ref. Guide.

(Table P0402)
Values for Chips&Technologies extension commands:
 00h    return ID - returns A6h for a C&T controller, part # N93N8042/A
 02h    write input port
    next data byte to PORT 0060h is written to the controller's input port
    Warning: the system must be designed to support output devices
          connected to the input port to avoid potential damage
 04h    select turbo switch input
    next byte selects input:
        bit 7: switch polarity
        (=0 input low = high speed, =1 input low = low speed)
        bits 6-0: one bit set selects corresponding bit in Port1 as turbo
 05h    select turbo LED output
    next byte selects output:
        bit 7: LED polarity    (=0 output low=LED on, =1 output low=LED off)
        bit 6: LED port (=0 Port1, =1 Port2)
        bits 5-0: one bit set selects corresponding bit in Port1/Port2 as
        LED output
Note:    these commands and any arguments are sent to PORT 0060h after writing
      command A1h to PORT 0064h
SeeAlso: #P0401

Bitfields for Compaq keyboard command byte:
Bit(s)    Description    (Table P0403)
 7    reserved
 6    =1 convert KB codes to 8086 scan codes
 5    =0 use 11-bit codes, 1=use 8086 codes
 4    =0 enable keyboard, 1=disable keyboard
 3    ignore security lock state
 2    this bit goes into bit2 status reg.
 1    reserved (0)
 0    generate interrupt (IRQ1) when output buffer full
SeeAlso: #P0404

Bitfields for keyboard command byte (alternate description):
Bit(s)    Description    (Table P0404)
 7    reserved (0)
 6    IBM PC compatibility mode
 5    IBM PC mode
    no parity, no stop bits, no translation
    (PS/2) force mouse clock low
 4    disable keyboard (clock)
 3    (AT) inhibit override -- ignore keyboard lock switch
    (PS/2) reserved
 2    system flag
 1    (AT) reserved (0)
    (PS/2) enable mouse output buffer full interrupt (IRQ12)
 0    enable output buffer full interrupt (IRQ1)
SeeAlso: #P0403,#P0405

Bitfields for keyboard controller output port:
Bit(s)    Description    (Table P0405)
 7    keyboard data (output)
 6    keyboard clock (output)
 5    (AT) =0 input buffer empty
    (MCA) outptu buffer full with mouse byte (connected to IRQ12)
 4    output buffer full with keyboard byte (connected to IRQ1)
 3    (MCA) mouse data (output)
 2    (MCA) mouse clock (output)
    used by Intel 386sx Chipset with AMI/Phoenix BIOSes for BIOS-specific
      configuration of turbo switch
 1    gate address A20
 0    system reset
Note:    bit 0 (system reset) should always be set when writing the output
      port, as the system may hang constantly; use pulse output port
      (command FEh) instead.
SeeAlso: #P0404

(Table P0406)
Values for keyboard/mouse test result on PORT 0060h:
 00h    no error
 01h    keyboard clock line stuck low
 02h    keyboard clock line stuck high
 03h    keyboard data line is stuck low
 04h    keyboard data line stuck high
 05h    (Compaq only) diagnostic feature
SeeAlso: #P0401

(Table P0407)
Values for keyboard controller RAM location:
 00h    command byte (see #P0403,#P0404)
---MCA systems---
 13h    security on
    nonzero if password enabled
 14h    security off
    nonzero if password matched
 16h    password discard scancode 1
 17h    password discard scancode 2
Note:    make codes matching either discard scancode are ignored during password
      entry
----------P0065------------------------------
PORT 0065 - AT&T 6300+ - HIGH/LOW CHIP SELECT
----------P0065------------------------------
PORT 0065 - ???

0065  RW  ???
        bit 2: A20 gate control (set = A20 enabled, clear = disabled)
----------P00660067--------------------------
PORT 0066-0067 - AT&T 6300+ - SYSTEM CONFIGURATION SWITCHES
----------P0066------------------------------
PORT 0066 - IBM 4717 Magnetic Stripe Reader - ???
SeeAlso: PORT 0069h"Magnetic Stripe"
----------P0068------------------------------
PORT 0068 - C&T CHIPSETS - TURBO MODE CONTROL

Note:      on Micronics 386-25/386-33/486-25 motherboards, setting this port to
        00h enables full speed; setting it to C0h slows the system down by
        a factor corresponding to the value programmed into the EISA
        interval timer 2 at ports 004Ah and 004Bh
--------K-P0068006F--------------------------
PORT 0068-006F - HP Vectra Human Interface Link
SeeAlso: PORT 0060h"KEYBOARD"

0068  -W  (HP-Vectra) control buffer (HP commands) (see #P0408)
0069  R-  (HP-Vectra) SVC (keyboard request SerViCe port)
006A  -W  (HP-Vectra) Acknowledge (clear processing, done)
006C-006F    HP-HIL    (Human Interface Link = async. serial inputs 0-7)

(Table P0408)
Values for HP Vectra control buffer command code:
 00h-54h insert standard key make code into 8041 scancode buf
 55h-77h insert HP key make code into 8041 scancode buffer
 7Ah    pass through next data byte
 7Bh    set RAM Switch to 0
 7Ch    set RAM Switch to 1 (default)
 7Dh    set CRT Switch to 0
 7Eh    set CRT Switch to 1 (default)
 7Fh    reserved
 80h-D4h insert standard key break code into scancode buffer
 D5h-F7h insert HP key break code into scancode buffer
 F8h    enable AutoPoll
 F9h    disable AutoPoll
 FAh-FEh reserved
 FFh    keyboard overrun
----------P0069------------------------------
PORT 0069 - IBM 4717 Magnetic Stripe Reader - ???
SeeAlso: PORT 0066h"Magnetic Stripe"
----------P006B006F--------------------------
PORT 006B-006F - SSGA CONTROL REGISTERS

006B  ??  RAM enable/remap
006C  ??  undocumented
006D  ??  undocumented
006E  ??  undocumented
006F  ??  undocumented
----------P0070007F--------------------------
PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK)
Note:    the real-time clock may be either a discrete MC146814, MC146818, or
      an emulation thereof built into the motherboard chipset
SeeAlso: PORT 00A0h"XT"

0070  -W  CMOS RAM index register port (ISA, EISA)
         bit 7    = 1  NMI disabled from reaching CPU
            = 0  NMI enabled
         bit 6-0     CMOS RAM index
            (64 bytes in early systems, now usually 128 bytes)
    Note:    any write to PORT 0070h should be followed by an action to
          PORT 0071h or the RTC wil be left in an unknown state.
0071  RW  CMOS RAM data port (ISA, EISA) (see #P0409)

(Table P0409)
Values for Real-Time Clock register number (see also CMOS.LST):
 00h-0Dh clock registers
 0Eh    diagnostics status byte
 0Fh    shutdown status byte
 10h    diskette drive type for A: and B:
 11h    reserved / IBM fixed disk / setup options
 12h    fixed disk drive type for drive 0 and drive 1
 13h    reserved / AMI Extended CMOS setup (AMI Hi-Flex BIOS)
 14h    equipment byte
 15h    LSB of system base memory in Kb
 16h    MSB of system base memory in Kb
 17h    LSB of total extended memory in Kb
 18h    MSB of total extended memory in Kb
 19h    drive C extension byte
 1Ah    drive D extension byte
 1Bh-2Dh reserved
 20h-27h commonly used for first user-configurable drive type
 2Eh    CMOS MSB checksum over 10-2D
 2Fh    CMOS LSB checksum over 10-2D
 30h    LSB of extended memory found above 1Mb at POST
 31h    MSB of extended memory found above 1Mb at POST
 32h    date century in BCD
 33h    information flags
 34h-3Fh    reserved
 35h-3Ch commonly used for second user-configurable drive type
 3Dh-3Eh word to 82335 MCR memory config register at [22] (Phoenix)
 42h-4Ch AMI 1990 Hyundai super-NB368S notebook
    ???
 54h-57h AMI 1990 Hyundai super-NB368S notebook
    ???
 5Ch-5Dh AMI 1990 Hyundai super-NB368S notebook
    ???
 60h-61h AMI 1990 Hyundai super-NB368S notebook
    ???
----------P0072------------------------------
PORT 0072 - Chips&Technologies 82C100 - NMI CONTROL

!!!chips\82c100.pdf p.41
----------P00720075--------------------------
PORT 0072-0075 - AMD-645 Peripheral Bus Controller - ACCESS TO EXTENDED CMOS
SeeAlso: PORT 0070h

0072  RW  CMOS memory address, region 2 (256 bytes)
0073  RW  CMOS memory data, region 2
0074  RW  CMOS memory address, region 3 (256 bytes)
0075  RW  CMOS memory data, region 3
Note:    on the AMD-645, ports 0072h and 0073h allow access to a full 256 bytes
      of RAM, including the standard 128 bytes available through ports
      0070h and 0071h
----------P0073------------------------------
PORT 0073 - Intel 82378IB ("Saturn"/"Neptune" chipsets) - MBOARD CONFIGURATION
SeeAlso: PORT 0075h

0073  RW  ???
    bit 7: ???
    bit 6: disable ROM shadowing
    bit 5: ??? (related to IDE controller)
    bit 4: ???
    bit 3: ???
----------P00740076--------------------------
PORT 0074-0076 - SECONDARY CMOS (Compaq), NVRAM (IBM) ACCESS
Note:    NVRAM may be 2K, 8K, or 16K
SeeAlso: PORT 0070h-007Fh,CMOS.LST

0074  -W  secondary CMOS RAM (IBM NVRAM) index, low byte
0075  -W  secondary CMOS RAM (IBM NVRAM) index, high (in bits 2-0)
0076  RW  secondary CMOS RAM (IBM NVRAM) data byte
----------P0075------------------------------
PORT 0075 - Intel 82378IB ("Saturn"/"Neptune" chipsets) - MBOARD CONFIGURATION
SeeAlso: PORT 0073h,PORT 0078h"82378IB"

0075  R-  ???
      bits 3-2: external bus speed
           00  50 MHz
           01  66 MHz
           10  60 MHz
           11  40 MHz
----------P0078------------------------------
PORT 0078 - HP-Vectra - HARD RESET: NMI ENABLE/DISABLE

0078  ?W  NMI enable/disable
        bit 7 = 0  disable & clear hard reset from HP-HIL controller
              = 1  enable hard reset from HP-HIL controller chip
        bit 6-0       reserved
----------P0078------------------------------
PORT 0078 - Intel 82378IB ("Saturn"/"Neptune" chipsets) - BIOS COUNT-DOWN TIMER
Notes:    the BIOS uses this port for certain fine timings; presumably it is
      independent of processor speed (it appears to decrement at 1 MHz)
    the address at which this port appears may be set via the 82378's
      PCI configuration space word at offset 0080h (see #01064), or the
      timer may be disabled entirely
SeeAlso: PORT 0075h

0078w -W  set count-down timer
0078w R-  get current count (timer stops when it reaches 0000h)
----------P0078007F--------------------------
PORT 0078-007F - PC radio by CoZet Info Systems
Range:    The I/O address range is dipswitch selectable from:
       038-03F and 0B0-0BF
       078-07F and 0F0-0FF
       138-13F and 1B0-1BF
       178-17F and 1F0-1FF
       238-23F and 2B0-2BF
       278-27F and 2F0-2FF
       338-33F and 3B0-3BF
       378-37F and 3F0-3FF
Note:    All of these addresses show a readout of FFh in initial state.
    Once started, all of the addresses show FBh, whatever might happen.
----------P007C007D--------------------------
PORT 007C-007D - HP-Vectra - PIC 3 - PROGRAMMABLE INTERRUPT CONTROLLER (8259)
Notes:    cascaded to first controller.
    used for keyboard and input device interface.
SeeAlso: PORT 0020h-0021h,INT 68"Vectra",INT 6E"Vectra"

007C  RW  HP-Vectra  PIC 3  see at 0020     PIC 1
007D  RW  HP-Vectra  PIC 3  see at 0021     PIC 1
----------P007E------------------------------
PORT 007E - Chips&Technologies 82C100/110 - NMI STATUS
SeeAlso: PORT 0072h"82C100",PORT 007Fh"82C100"
!!!chips\82c100.pdf p.42
!!!chips\82c110.pdf p.39
----------P007F------------------------------
PORT 007F - Chips&Technologies 82C100/110 - POWER CONTROL AND RESET
SeeAlso: PORT 0072h"82C100",PORT 007Eh"82C100"
----------P0080------------------------------
PORT 0080 - MANUFACTURING DIAGNOSTICS PORT
Note:    sometimes used for a POST hex display

0080  -W  Manufacturing Diagnostics port
0080  R-  ???

(Table P0410)
Values for AMI BIOS diagnostics codes:
 00h    system boot completed, control passed to INT 19 bootstrap loader
 01h    register test
 02h    video initialization; NMIs disabled
 03h    power-on delay complete
 04h    pre-keyboard-test initializations complete
 05h    soft-reset/power-on setting determined
 06h    ROM enabled
 07h    ROM BIOS checksum test passed
 08h    keyboard BAT command issued
 09h    keyboard controller BAT result verified
 0Ah    keyboard controller command code issued
 0Bh    keyboard controller command byte written
 0Ch    keyboard controller pins 23/24 blocked and unblocked
 0Dh    keyboard controller NOP processing in progress
 0Eh    CMOS RAM shutdown register read/write test passed
 0Fh    CMOS RAM checksum calculation complete
 10h    CMOS RAM initialization complete
 11h    CMOS RAM status register initialized
 12h    DMA controllers 1/2 and interrupt controllers 1/2 disabled
 13h    video display disabled, port B initialized
 14h    chipset initialization, auto memory detection
 15h    8254 channel 2 test half complete
 16h    8254 channel 2 test completed
 17h    8254 channel 1 test completed
 18h    8254 channel 0 test completed
 19h    memory refresh started
 1Ah    memory refresh line is toggling
 1Bh    memory refresh test completed
 20h    base 64K memory test started
 21h    address line test passed
 22h    parity toggle complete
 23h    base 64K sequential read/write test passed
 24h    pre-interrupt-vector-initialization configuration complete
 25h    interrupt vectors initialized
 26h    8042 input port read
 27h    global data initialization complete
 28h    post-interrupt-vector-initialization initialization complete
 29h    monochrome mode set
 2Ah    color mode set
 2Bh    parity toggle on option video ROM test complete
 2Ch    initialization before video ROM control complete
 2Dh    video ROM check complete
 2Eh    !!!
 A9h    returned from E0000h adapter ROM
 AAh    final initializations after adapter ROM initializations complete
SeeAlso: #P0411,#P0412,#P0413

(Table P0411)
Values for AWARD (non-PnP) diagnostic code:
 01h    Processor Test 1
 02h    Processor Test 2
 03h    initialize chips
 04h    test memory refresh toggle
 05h    blank video, initialize keyboard
 06h    reserved
 07h    test CMOS and CMOS batter status
 08h    setup low memory
 09h    early cache initialization
 0Ah    interrupt vector initialization
 0Bh    test CMOS RAM checksum
 0Ch    initialize keyboard
 0Dh    initialize video interface
 0Eh    test video memory
 0Fh    test DMA channel 0
 10h    test DMA channel 1
 11h    test DMA page registers
 12h    reserved
 13h    reserved
 14h    test timer channel 2
 15h    test master PIC mask bits
 16h    test slave PIC mask bits
 17h    test 8259 stuck interrupt bits
 18h    test 8259 interrupt functionality
 19h    test for stuck NMI
 1Ah    display CPU clock
 1Bh-1Eh reserved
 1Fh    set EISA mode
 20h    enable Slot 0 (system board)
 21h-2Fh enable Slots 1-15
 30h    get base and extended memory size
 31h    test base and extended memory
 32h    test EISA memory
 33h-3Bh reserved
 3Ch    set allow-setup flag
 3Dh    initialize / install mouse
 3Eh    initialize cache controller
 3Fh    reserved
 41h    initialize floppy controller and drives
 42h    initialize hard disk controller and drives
 43h    detect / initialize serial and parallel ports
 44h    reserved
 45h    initialize math coprocessor
 46h-4Dh reserved
 4Eh    Manufacturing Post loop / or / display any error messages
 4Fh    ask for password, if enabled
 50h    update CMOS RAM
 51h    pre-boot enable of parity, NMI, cache
 52h    initialize option ROMs
 53h    initialize BIOS time from RTC
 60h    setup boot-sector protection
 61h    set boot CPU speed
 62h    setup NumLock
 63h    attempt to boot via INT 19h
 B0h    spurious interrupt while in protected mode
 B1h    unclaimed NMI
 BEh    chipset default initialization
 BFh    chipset initialization
 C0h    turn off chipset cache
 C1h    check on-board memory size
 C5h    early shadow-RAM enable for faster boot
 C6h    detect external cache size
 E1h-EFh setup utility pages 1-15
 FFh    system booting operating system
SeeAlso: #P0410,#P0412,#P0413

(Table P0412)
Values for AWARD (Plug-and-Play) POST code:
 01h-02h reserved
 03h    initialize EISA register (if applicable)
 04h    reserved
 05h    keyboard controller test, initialize keyboard
 06h    reserved
 07h    test CMOS and CMOS batter status
 09h    program Cyrix CPU configuration; OEM-specific cache initialization
 0Ah    initialize interrupt vectors; early power management initialization
 0Bh    check CMOS RAM; assign I/O and memory to PCI devices
 0Ch    initialize BIOS data area
 0Dh    early chipset setup; measure CPU speed; video initialization
 0Eh    display Award logo, OEM-specific sign-on messages
 0Fh    test DMA channel 0
 10h    test DMA channel 1
 11h    test DMA page registers
 12h-13h reserved
 14h    test timer channel 2
 15h    test master PIC mask bits
 16h    test slave PIC mask bits
 17h    reserved
 19h    test 8259 functionality
 1Ah-1Dh reserved
 1Eh    EISA initialization (if applicable and EISA NVRAM checksum is good)
 1Fh-29h reserved
 30h    get base and extended memory size
 31h    test base and extended memory
 32h    program on-board serial/parallel ports, floppy controller
 33h-3Bh reserved
 3Ch    set allow-setup flag
 3Dh    initialize keyboard, install PS/2 mouse if attached
 3Eh    try to turn on L2 cache
 3Fh-40h reserved
 41h    initialize floppy controller, drives
 42h    initialize hard disk controller, drives
 43h    initialize serial/parallel ports (if PnP)
 44h    reserved
 45h    initialize math coprocessor
 46h-4Dh reserved
 4Eh    display any error messages
 4Fh    ask for password, if required
 50h    update CMOS RAM
 51h    reserved
 52h    initialize expansion ROMs, PCI, PnP, shadow RAM, power management
 53h    if not PnP, initialize serial/parallel ports; set BIOS time
 54h-5Fh reserved
 60h    set boot-sector protection
 61h    turn on L2 cache; set boot speed; final chipset/PM initialization
 62h    setup daylight savings time; set NumLock, typematic
 63h    update ESCD (PnP only) if changes; boot system via INT 19h
 B0h    spurious interrupt while in protected mode
 B1h    unclaimed NMI
 BEh    chipset default initialization
 BFh    chipset initialization
 C0h    turn off chipset cache, init DMA/PIC/timer/RTC with default values
 C1h    check on-board DRAM and cache size
 C3h    test first 256K DRAM, expand compressed BIOS image into DRAM
 C5h    early shadow-RAM enable for faster boot
 FFh    system is booting operating system
SeeAlso: #P0410,#P0411,#P0413

(Table P0413)
Values for Chips&Technologies 82C100/82C235 POST code:
 01h    flags register failed
 02h    a CPU register failed
 03h    incorrect ROM checksum
 04h    DMA controller failed
 05h    system timer failed
 06h    first 64K of RAM failed address test
 07h    first 64K of RAM failed RAM test
 08h    interrupt controller failed
 09h    "Hot Interrupt" occurred
 0Ah    reserved
 0Bh    CPU still in protected mode
 0Ch    DMA page register failed
 0Dh    no RAM refresh
 0Eh    no response from keyboard controller
 0Fh    unable to enter protected mode
 10h    GDT or IDT register failed
 11h    LDT register failed
 12h    task register failed
 13h    LSL instruction failed
 14h    LAR instruction failed
 15h    VERR or VERW instruction failed
 16h    keyboard controller A20 gate failed
 17h    exception failed, or shutduwon on unexpected exception
 18h    shutdown during memory test
 19h    checksum error in copyright string
 1Ah    BMS checksum error
---POST progress codes---
 50h    initialize hardware
 51h    initialize timer
 52h    initialize DMA controller
 53h    initialize 8259
 54h    initialize chipset
 55h    reserved
 56h    first entry into protected mode
 57h    memory-chip sizing
 58h    reserved
 59h    first exit from protected mode
 5Ah    system-board memory size determination
 5Bh    shadow RAM relocation
 5Ch    configure possible EMS
 5Dh    reserved
 5Eh    re-test lowest 64K of RAM
 5Fh    test shadow RAM
 60h    test CMOS RAM
 61h    test video
 63h    test protected mode interrupts
 64h    test A20
 65h    memory address line tests
 66h    test base memory
 67h    test extended memory
 68h    test timer interrupt
 69h    test real-time clock
 6Ah    test keyboard controller
 6Bh    test 80287
 6Ch    test RS232
 6Dh    test parallel port
 6Eh    reserved
 6Fh    test floppy disk controller
 70h    test fixed disk controller
 71h    test keylock
 72h    test mouse / pointing device
 73h-8Fh reserved
 90h    setup RAM
 91h    determine CPU speed
 92h    configuration check
 93h    initialize BIOS
 94h    POD bootstrap
 95h    reset ICs
 96h    setup cache controller
SeeAlso: #P0410,#P0411,#P0412

(Table P0414)
Values for Intel SE440BX ("Seattle") motherboard POST codes:
 02h    verify real mode
 03h    disable NMI
 04h    CPU type determination
 06h    system hardware initialization
 08h    chipset initialization (initial POST values)
 09h    set IN-POST flag
 0Ah    CPU register initialization
 0Bh    enable CPU cache
 0Ch    cache initialization (initial POST values)
 0Eh    I/O component initialization
 0Fh    local-bus IDE initialization
 10h    power management initialization
 11h    load alternate rgisters with initial POST values
 12h    warm boot: restore CPU control word
 13h    PCI bus-mastering device initialization
 14h    keyboard controller initialization
 16h    checksum BIOS ROM
 17h    cache initialization (before memory autosizing)
 18h    initialize 8254 timer
 1Ah    8237 DMA controller initialization
 1Ch    programmable interrupt controller reset
 20h    DRAM refresh test
 22h    keyboard controller test
 24h    ES register set to 4G flat
 26h    A20 enabled
 28h    DRAM autosizing
 29h    POST memory manager initialization
 2Ah    512K base RAM cleared
 2Ch    RAM failure on address line xxxx
 2Eh    RAM failure on data bits xxxx of memory bus low byte
 2Fh    cache enabled before system BIOS shadowing
 30h    RAM failure on data bits xxxx of memory bus high byte
 32h    CPU bus-clock frequency test
 33h    POST dispatch manager initialization
 34h    CMOS RAM test
 35h    alternate chipset register initialization
 36h    warm start shutdown
 37h    chipset reinitialization (motherboard)
 38h    system BIOS ROM shadowing
 39h    cache reinitialization (motherboard)
 3Ah    cache autosizing
 3Ch    advanced chipset register configuration
 3Dh    load alternate registers with CMOS values
 40h    initial CPU speed set
 42h    interrupt vector initialization
 44h    BIOS interrupt initialization
 45h    POST device initialization
 46h    ROM copyright notice check
 47h    PCI option ROM manager initialization
 48h    check video configuration against CMOS RAM data
 49h    PCI bus and device initialization
 4Ah    video adapter initialization
 4Bh    display QuietBoot screen
 4Ch    vidoe BIOS ROM shadowing
 4Eh    display BIOS copyright notice
 50h    display CPU type and speed
 51h    EISA motherboard initialization
 52h    keyboard test
 54h    set key click (if enabled)
 56h    enable keyboard
 58h    test for unexpected interrupts
 59h    POST display service initialization
 5Ah    display prompt "Press F2 to enter SETUP"
 5Bh    disable CPU cache
 5Ch    RAM test (512K-640K)
 60h    extended memory test
 62h    extended memory address line test
 64h    jump to UserPatch1
 66h    advanced cache register configuration
 67h    multiprocessor APIC initialization
 68h    enable L1 and L2 caches
 69h    SMM area setup
 6Ah    display L2 cache size
 6Ch    display    shadow-area message
 6Eh    display possible UMB recovery high address
 70h    display error messages
 72h    configuration error check
 74h    real-time clock test
 76h    keyboard-error check
 7Ah    test for key lock on
 7Ch    hardware interrupt vector setup
 7Eh    coprocessor initialization (if present)
 80h    disable onboard SuperI/O ports and IRQs
 81h    late POST device initialization
 82h    detect/install external serial ports
 83h    non-MCD IDE controller configuration
 84h    detect/install external parallel ports
 85h    PC-compatible PnP ISA device initialization
 86h    onboard I/O port reinitialization
 87h    configure motherboard configurable devices
 88h    BIOS data area initialization
 89h    enable NMI
 8Ah    extended BIOS data area initialization
 8Bh    test/initialize PS/2 mouse
 8Ch    diskette controller initialization
 8Fh    determine number of ATA drives
 90h    hard-disk controller initialization
 91h    local-bus hard-disk controller initialization
 92h    jump to UserPatch2
 93h    build MPTABLE for multiprocessor boards
 94h    disable A20 (Release 5.1 and earlier)
 95h    install CD-ROM for boot
 96h    clear ES 4G segment register
 97h    multiprocessor table fixup
 98h    option ROM search
 99h    check for SMART drive
 9Ah    option ROM shadowing
 9Ch    power management setup
 9Eh    enable hardware interrupts
 9Fh    determine number of ATA and SCSI devices
 A0h    set time of day
 A2h    check key lock
 A4h    typematic rate initialization
 A8h    erase F2 prompt
 AAh    test for F2 keystroke
 ACh    enter SETUP
 AEh    clear IN-POST flag
 B0h    check for errors
 B2h    preparing to boot OS - POST complete
 B4h    short beep before booting
 B5h    terminate QuietBoot
 B6h    password check (optional)
 B8h    clear global descriptor table
 B9h    clean up all graphics
 BAh    DMI parameter initialization
 BBh    PnP option ROM initialization
 BCh    clear parity checkers
 BDh    display MultiBoot menu
 BEh    clear screen (optional)
 BFh    check virus and backup reminders
 C0h    INT 19 boot attempt
 C1h    POST Error Manager (PEM) initialization
 C2h    error logging initialization
 C3h    error display function initialization
 C4h    system error handler initialization
 E0h    chipset initialization
 E1h    bridge initialization
 E2h    processor initialization
 E3h    system timer initialization
 E4h    system I/O initialization
 E5h    check force recovery boot
 E6h    BIOS ROM checksumming
 E7h    go to BIOS
 E8h    set huge segment
 E9h    multiprocessor initialization
 EAh    OEM special code initialization
 EBh    PIC and DMA initialization
 ECh    memory type initialization
 EDh    memory size initialization
 EEh    boot block shadowing
 EFh    system memory test
 F0h    interrupt vector initialization
 F1h    real-time clock initialization
 F2h    video initialization
 F3h    beeper initialization
 F4h    initialize boot
 F5h    clear huge segment
 F6h    boot to mini-DOS
 F7h    boot to full DOS
----------P0080008F--------------------------
PORT 0080-008F - DMA PAGE REGISTERS (74612)

0080  RW  extra page register (temporary storage)
0081  RW  DMA channel 2 address byte 2
0082  RW  DMA channel 3 address byte 2
0083  RW  DMA channel 1 address byte 2
0084  RW  extra page register
0085  RW  extra page register
0086  RW  extra page register
0087  RW  DMA channel 0 address byte 2
0088  RW  extra page register
0089  RW  DMA channel 6 address byte 2
008A  RW  DMA channel 7 address byte 2
008B  RW  DMA channel 5 address byte 2
008C  RW  extra page register
008D  RW  extra page register
008E  RW  extra page register
008F  RW  DMA refresh page register
----------P0080009F--------------------------
PORT 0080-009F - Intel386sx CHIPSET 82231
Note:    includes the DMA controller functionality on PORT 0080h to PORT 008Fh
----------P0084------------------------------
PORT 0084 - Compaq POST Diagnostic
--------X-P0084------------------------------
PORT 0084 - EISA - SYNCHRONIZE BUS CYCLE
----------P00850086--------------------------
PORT 0085-0086 - Intel "Triton" chipset - ???
SeeAlso: PORT 00EBh"Triton"

0085  ?W  ???
0086  ?W  ???
----------P0090009F--------------------------
PORT 0090-009F - PS/2 - POS (PROGRAMMABLE OPTION SELECT)

0090  ??  Central arbitration control port
0090  RW  POST diagnostic code (most PS/2 with ISA bus)
0091  R-  Card selection feedback
        bit 0 set when adapter addressed and responds, cleared on read
0092  RW  PS/2 system control port A  (port B is at PORT 0061h) (see #P0415)
0094  -W  system board enable/setup register (see #P0416)
0095  --  reserved
0096  -W  adapter enable / setup register (see #P0417)
0097  --  reserved

Bitfields for PS/2 system control port A:
Bit(s)    Description    (Table P0415)
 7-6    any bit set to 1 turns activity light on
 5    unused
 4    watchdog timout occurred
 3    =0 RTC/CMOS security lock (on password area) unlocked
    =1 CMOS locked (done by POST)
 2    unused
 1    A20 is active
 0    =0 system reset or write
    =1 pulse alternate reset pin (high-speed alternate CPU reset)
Notes:    once set, bit 3 may only be cleared by a power-on reset
    on at least the C&T 82C235, bit 0 remains set through a CPU reset to
      allow the BIOS to determine the reset method
SeeAlso: #P0416,#P0417,MSR 00001000h

Bitfields for PS/2 system board enable/setup register:
Bit(s)    Description    (Table P0416)
 7    =1  enable functions
    =0  setup functions
 5    =1  enables VGA
    =0  setup VGA
 2    =1  enable integrated SCSI (PS/2 M77)
    =0  setup integrated SCSI
SeeAlso: #P0415,#P0417

Bitfields for PS/2 adapter enable/setup register:
Bit(s)    Description    (Table P0417)
 7    activate Channel Reset on all slots
 6-4    unused (1)
 3    =1  setup adapter specified by bits 2-0
    =0  enable registers
 2-0    adapter slot select (000 = slot 1 ... 111 = slot 8)
SeeAlso: #P0416
----------P00A000AF--------------------------
PORT 00A0-00AF - PIC 2 - PROGRAMMABLE INTERRUPT CONTROLLER (8259A)
SeeAlso: PORT 0020h-003Fh"PIC 1",INT 70"IRQ8",INT 77"IRQ15"

00A0  RW  PIC 2     same as 0020 for PIC 1
00A1  RW  PIC 2     same as 0021 for PIC 1 except for OCW1 (see #P0418)

Bitfields for PIC2 output control word OCW1:
Bit(s)    Description    (Table P0418)
 7    disable IRQ15 (reserved)
 6    disable IRQ14 (fixed disk interrupt)
 5    disable IRQ13 (coprocessor exception interrupt)
 4    disable IRQ12 (mouse interrupt)
 3    disable IRQ11 (reserved)
 2    disable IRQ10 (reserved)
 1    disable IRQ9  (redirect cascade)
 0    disable IRQ8  (real-time clock interrupt)
SeeAlso: #P0014
----------P00A0------------------------------
PORT 00A0 - XT - NMI MASK REGISTER
SeeAlso: PORT 0070h,INT 02

00A0  RW  NMI mask register (XT only)
     bit 7 = 0 NMI signal disabled from reaching CPU
           = 1 NMI signal enabled
----------P00A000AF--------------------------
PORT 00A0-00AF - Chips&Technologies 82C100/110 - NMI CONTROL
SeeAlso: PORT 0072h"82C100",PORT 007Fh"82C100"

00A0  RW  NMI mask register (XT only)
     bit 7 = 0 NMI signal disabled from reaching CPU
           = 1 NMI signal enabled
00Ax  RW  mirrors of PORT 00A0h
----------P00A800A9--------------------------
PORT 00A8-00A9 - Via VT82C496G "Pluto" - CONFIGURATION REGISTERS
SeeAlso: PORT 00A8h"VT82C570M"

00A8  ?W  configuration register index (see #P0419)
00A9  RW  configuration register data

(Table P0419)
Values for Via VT82C496G configuration registers:
 02h    clock throttling control (see #P0420)
 03h    I/O recovery (see #P0421)
 10h    bus speed (see #P0422)
 11h    ISA bus clock frequency control (see #P0423)
 20h    pair 0/1 row/column address (see #P0424)
 21h    pair 2/3 row/column address (see #P0425)
 22h    RAS#/CAS# pulse control (see #P0426)
 30h    C0000h-CFFFFh shadow control (see #P0427)
 31h    D0000h-DFFFFh shadow control (see #P0428)
 32h    E0000h-FFFFFh shadow control (see #P0429)
 33h    ROM decoding and memory relocation (see #P0430)
 40h    ROM cacheable control (see #P0431)
 41h    programmable non-cacheable region ???
 42h    programmable non-cacheable region ???
 43h    pair 0/1 DRAM size and configuration (see #P0432)
 44h    pair 2/3 DRAM size and configuration (see #P0433)
 50h    cache access mode (see #P0434)
 51h    cache timing/size control (see #P0435)
 52h    primary idle timer reloading control (see #P0436)
 53h    primary idle timer reload distinguish (see #P0437)
 54h    SMI triggering control (see #P0438)
 55h    SMI trigger distinguish (see #P0439)
 56h    clock frequency control (see #P0440)
 57h    peripheral timer (see #P0441)
 58h    general purpose timer (see #P0442)
 59h    timer control (see #P0443)
 5Ah    power/peripheral control (see #P0444)
 5Bh    system management control (see #P0445)
 5Ch    clock switching control (see #P0446)
 5Dh    peripheral timer control (see #P0447)
 5Eh    misc. cache control (see #P0448)
 5Fh    conserve mode/secondary idle timer control (see #P0449)
 60h    IRQ7-0 primary interrupt selection (see #P0450)
 61h    IRQ15-8 primary interrupt selection (see #P0451)
 62h    IRQ7-3 interrupt mode and global control (see #P0452)
 63h    IRQ15-9 interrupt mode (see #P0453)
 64h    (see #P0454)
 65h    peripheral timer control (see #P0455)
 68h    port 070h write shadow
 69h    port 2F8h write shadow
 6Ah    port 3F8h write shadow
 6Bh    port 372h write shadow
 6Ch    port 377h write shadow
 6Dh    port 171h write shadow
 6Eh    port 177h write shadow
 6Fh    port 376h write shadow
 71h    IDE controller/cache control (see #P0456)
 72h    non-1F0/170h port access timing (see #P0457)
 73h    drive #0 read timing for 1F0/170h access (see #P0458)
 74h    drive #0 write timing for 1F0/170h access (see #P0459)
 77h    drive #0 address setup time (see #P0460)
 78h    drive #1 read timing for 1F0/170h access (see #P0458)
 79h    drive #1 write timing for 1F0/170h access (see #P0459)
 7Ch    drive #1 address setup time (see #P0460)
SeeAlso: #P0461

Bitfields for Via VT82C496G/VT82C570M clock throttling control:
Bit(s)    Description    (Table P0420)
 4    STPCLK# throttling period (enabled by register 5Bh bit 0)
    0 = 3.35 µs * 16
    1 = 1.7 ms * 16
 3-0    duty cycle for STPCLK# (1/16 - 15/16) (enabled by register 5Bh bit 0)
SeeAlso: #P0419,#P0445

Bitfields for Via VT82C496G/VT82C570M register 03h:
Bit(s)    Description    (Table P0421)
 7-1    (VT82C496G) command delay, wait state and I/O recovery time for normal
      ISA cycles ???
 0    decoupled DRAM refresh enable
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M register 10h:
Bit(s)    Description    (Table P0422)
 6    DMA controller runs at ISA clock speed/half ISA clock speed
SeeAlso: #P0419,#P0423

Bitfields for Via VT82C496G/VT82C570M ISA bus clock frequency control:
Bit(s)    Description    (Table P0423)
 6    flash EPROM write cycle support enable
 3-0    ISA bus clock frequency
    0xxx = CLKIN / 8
    1000 = CLKIN / 3
    1001 = CLKIN / 2
    1010 = CLKIN / 4
    1011 = CLKIN / 6
    1100 = CLKIN / 5
    1101 = CLKIN / 10
    1110 = CLKIN / 12
    1111 = OSC / 2 (asynchronous)
SeeAlso: #P0419,#P0422

Bitfields for Via VT82C496G/VT82C570M pair 0/1 row/column address:
Bit(s)    Description    (Table P0424)
 7-5    number of column address bits for pair 0
    000 = disabled
    001 = 9 bit
    010 = 10 bit
    011 = 11 bit
    100 = 12 bit
    101-111 = illegal
 4    page mode operation enable
 3-1    number of column address bits for pair 1 (same values as above)
 0    (VT82C496G) reserved
    (VT82C570M) DRAM bus width
    0 = 32 bit
    1 = 64 bit (operation width set in register 48h bits 3-0)
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M pair 2/3 row/column address:
Bit(s)    Description    (Table P0425)
 7-5    number of column address bits for pair 2
    000 = disabled
    001 = 9 bit
    010 = 10 bit
    011 = 11 bit
    100 = 12 bit
    101-111 = illegal
 4    reserved
 3-1    number of column address bits for pair 3 (same values as above)
 0    reserved
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M RAS#/CAS# pulse control:
Bit(s)    Description    (Table P0426)
 7-6    RAS# precharge time
    00-11 = (VT82C496G) 1-4 cycles
        (VT82C570M) 2-8 cycles
 5-4    RAS# pulse width
    00-11 = (VT82C496G) 2-5 cycles
        (VT82C570M) 4-10 cycles
 3-2    read cycle CAS# pulse width
    00-11 = 1-4 cycles
 1    write cycle CAS# pulse width
    0 = 1 cycle
    1 = 2 cycles
 0    RAS# to column address/column address to CAS#
    0 = 1 cycle
    1 = 2 cycles
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M C0000h-CFFFFh shadow control:
Bit(s)    Description    (Table P0427)
 7    CC000h-CFFFFh read shadow enable
 6    CC000h-CFFFFh write shadow enable
 5    C8000h-CBFFFh read shadow enable
 4    C8000h-CBFFFh write shadow enable
 3    C4000h-C7FFFh read shadow enable
 2    C4000h-C7FFFh write shadow enable
 1    C0000h-C3FFFh read shadow enable
 0    C0000h-C3FFFh write shadow enable
SeeAlso: #P0419,#P0428,#P0429

Bitfields for Via VT82C496G/VT82C570M D0000h-DFFFFh shadow control:
Bit(s)    Description    (Table P0428)
 7    DC000h-DFFFFh read shadow enable
 6    DC000h-DFFFFh write shadow enable
 5    D8000h-DBFFFh read shadow enable
 4    D8000h-DBFFFh write shadow enable
 3    D4000h-D7FFFh read shadow enable
 2    D4000h-D7FFFh write shadow enable
 1    D0000h-D3FFFh read shadow enable
 0    D0000h-D3FFFh write shadow enable
SeeAlso: #P0419,#P0427,#P0429

Bitfields for Via VT82C496G/VT82C570M E0000h-FFFFFh shadow control:
Bit(s)    Description    (Table P0429)
 7    E0000h-EFFFFh read shadow enable
 6    E0000h-EFFFFh write shadow enable
 5    F0000h-FFFFFh read shadow enable
 4    F0000h-FFFFFh write shadow enable
 3    ???
 2    memory range F00000h-FFFFFFh decode as ISA cycle enable
 1    (VT82C496G) burstable DRAM cycles enable
    (VT82C570M) ???
 0    ???
SeeAlso: #P0419,#P0427,#P0428,#P0430

Bitfields for Via VT82C496G/VT82C570M ROM decoding and memory relocation:
Bit(s)    Description    (Table P0430)
 7    C8000h-CFFFFh decoded as ROM cycle enable
 6    C0000h-C7FFFh decoded as ROM cycle enable
 5    E8000h-EFFFFh decoded as ROM cycle enable
 4    E0000h-E7FFFh decoded as ROM cycle enable
 3-2    memory relocation
    00 = disable
    01 = illegal
    10 = 256K relocation
    11 = 384K relocation
 1    (VT82C496G) RAS time-out
    (VT82C570M) ???
 0    ???
SeeAlso: #P0419,#P0429,#P0431

Bitfields for Via VT82C496G/VT82C570M ROM cacheable control:
Bit(s)    Description    (Table P0431)
 7    C0000h-C7FFFh cacheable and write-protect enable
 6    F0000h-FFFFFh cacheable and write-protect enable
 5    E0000h-EFFFFh cacheable and write-protect enable
 4    ???
 3    CAS-to-RAS refresh enable
 2    (VT82C570M) secondary cache fill for CACHE# inactive memory cycles
      enable
 1-0    ???
SeeAlso: #P0419,#P0430

Bitfields for Via VT82C496G/VT82C570M pair 0/1 DRAM size and configuration:
Bit(s)    Description    (Table P0432)
 7-5    (VT82C496G) bank-pair 0 DRAM size (x2 if double bank)
    000 = 512 KB
    001 = 1 MB
    010 = 2 MB
    011 = 4 MB
    100 = 8 MB
    101 = 16 MB
    110 = 32 MB
    111 = 64 MB
    (VT82C570M) bank-pair 0 DRAM size (x2 if double bank)
    000 = 1 MB
    001 = 2 MB
    010 = 4 MB
    011 = 8 MB
    100 = 16 MB
    101 = 32 MB
    110 = 64 MB
    111 = 128 MB
 4    number of banks in pair 0
    (0 bank if register 20h bit 7-5 = 0)
    0 = 1 bank
    1 = 2 banks
 3-1    (VT82C496G) bank-pair 1 DRAM size (x2 if double bank)
    (VT82C570M) bank-pair 1 DRAM size (x2 if double bank)
 0    number of banks in pair 1
    (0 bank if register 20h bit 3-1 = 0)
    0 = 1 bank
    1 = 2 banks
SeeAlso: #P0419,#P0433

Bitfields for Via VT82C496G/VT82C570M pair 2/3 DRAM size and configuration:
Bit(s)    Description    (Table P0433)
 7-5    (VT82C496G) bank-pair 2 DRAM size (x2 if double bank)
    000 = 512 KB
    001 = 1 MB
    010 = 2 MB
    011 = 4 MB
    100 = 8 MB
    101 = 16 MB
    110 = 32 MB
    111 = 64 MB
    (VT82C570M) bank-pair 2 DRAM size (x2 if double bank)
    000 = 1 MB
    001 = 2 MB
    010 = 4 MB
    011 = 8 MB
    100 = 16 MB
    101 = 32 MB
    110 = 64 MB
    111 = 128 MB
 4    number of banks of pair 2 (no banks if register 21h bit 7-5 = 0)
    0 = 1 bank
    1 = 2 banks
 3-1    (VT82C496G) bank-pair 3 DRAM size (x2 if double bank)
    (VT82C570M) bank-pair 3 DRAM size (x2 if double bank)
    (same values as for bits 7-5)
 0    number of banks of pair 3 (no banks if register 21h bit 3-1 = 0)
    0 = 1 bank
    1 = 2 banks
SeeAlso: #P0419,#P0432

Bitfields for Via VT82C496G/VT82C570M cache access mode:
Bit(s)    Description    (Table P0434)
 7-6    cache mode
    0x = disabled
    10 = enabled
    11 = initialization
 5    (VT82C496G) direct data SRAM access
    (VT82C570M) Cyrix CPU linear burst order enable
 4    (VT82C496G) write-back cache alter bit control (don't care for write
      through)
    0 = combined tag/alter bit
    1 = no alter bit
 4-3    (VT82C570M) number of tag/alter bits
      write-back (register 5Eh bit 6 = 0)
           tag   alter   total
      00     8     0     8
      01     7     1     8
      10     8     1     9
      11    10     1    11
      write-through (register 5Eh bit 6 = 1)
           tag   alter   total
      x0     8     -     8
      01     7     -     N/A
      11    10     -    10
 3-2    (VT82C496G) cache line size
    00 = 4 bytes
    01 = 8 bytes
    10 = 16 bytes
    11 = 4 bytes
 2    (VT82C570M) data synchronous SRAM type (if register 51h bit 4 = 0)
    0 = standard synchronous SRAM
    1 = pipelined burst synchronous SRAM
 1    (VT82C496G) burst write enable
    (VT82C570M) cache read wait state for PCI masters (PCI clock)
    0 = zero wait state (2-1-1-1)
    1 = one wait state (3-2-2-2)
 0    (VT82C496G) data streaming enable
    (VT82C570M) cache write wait state for PCI masters (PCI clock)
    0 = zero wait state (2-1-1-1)
    1 = one wait state (3-2-2-2)
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M cache timing/size control:
Bit(s)    Description    (Table P0435)
 7    (VT82C496G) read hit timing
    0 = 2-X-X-X
    1 = 3-X-X-X
    (VT82C570M) read hit timing for first cycle (CPU clock) for
      asynchronous SRAM
    0 = 1 wait state (2-X-X-X)
    1 = 2 wait state (3-X-X-X)
 6    (VT82C496G) write hit timing
    0 = 2-X-X-X
    1 = 3-X-X-X
    (VT82C570M) write hit timing for first cycle (CPU clock) for
      asynchronous SRAM
    0 = 1 wait state (3-X-X-X)
    1 = 2 wait state (4-X-X-X)
 5    (VT82C496G) read hit timing
    0 = X-1-1-1
    1 = X-2-2-2
    (VT82C570M) read hit timing for second-fourth burst cycle (CPU clock)
      for asynchronous SRAM
    0 = 1 wait state (X-2-2-2)
    1 = 2 wait state (X-3-3-3)
 4    (VT82C496G) write hit timing
    0 = X-1-1-1
    1 = X-2-2-2
    (VT82C570M) data SRAM type
    0 = synchronous SRAM (type set in register 50h bit 2)
    1 = asynchronous SRAM
 3    bank of data SRAM
    0 = 1 bank
    1 = 2 banks
 2-0    cache size
    000 = no cache
    001 = (VT82C496G) 32 KB
    010 = (VT82C496G) 64 KB
    011 = 128 KB
    100 = 256 KB
    101 = 512 KB
    110 = 1 MB
    111 = (VT82C570M) 2 MB
Note:    (VT82C570M) write hit timing is always 1 wait state (X-2-2-2) for
      asynchronous SRAM; read/write hit timing is always 3-1-1-1 for
      synchronous SRAM
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M primary idle timer reloading control:
Bit(s)    Description    (Table P0436)
 7    reload primary idle timer on keyboard access
 6    reload primary idle timer on serial port access
 5    reload primary idle timer on parallel port access
 4    reload primary idle timer on video access
 3    reload primary idle timer on hard disk and floppy access
 2    reload primary idle timer on IO port 100h-3FFh access
 1    reload primary idle timer on external input
 0    reload primary idle timer on DRQ/LREQ (DMA/local bus master request)
SeeAlso: #P0419,#P0437,#P0438

Bitfields for Via VT82C496G/VT82C570M primary idle timer reload distinguish:
Bit(s)    Description    (Table P0437)
 7    primary idle timer reloaded by keyboard access
 6    primary idle timer reloaded by serial port access
 5    primary idle timer reloaded by parallel port access
 4    primary idle timer reloaded by video access
 3    primary idle timer reloaded by hard disk and floppy access
 2    primary idle timer reloaded by IO port 100h-3FFh access
 1    primary idle timer reloaded by external input
 0    primary idle timer reloaded by DRQ/LREQ (DMA/local bus master request)
SeeAlso: #P0419,#P0436,#P0438

Bitfields for Via VT82C496G/VT82C570M SMI triggering control:
Bit(s)    Description    (Table P0438)
 7    trigger SMI on primary idle timer time-out
 6    trigger SMI on general purpose timer time-out
 5    trigger SMI on primary activity occurrence
 4    trigger SMI on primary interrupt occurrence
 3    trigger SMI on external pin (Turbo) toggle
 2    (VT82C496G) trigger SMI on DRQ/LREQ occurrence
    (VT82C570M) trigger SMI on DRQ/PREQ occurrence
 1    trigger SMI on peripheral timer or secondary idle timer
      time-out
    (VT82C496G) (use register 65h bits 3 and 2 to distinguish)
 0    trigger SMI on software SMI
SeeAlso: #P0419,#P0436,#P0438,#P0439

Bitfields for Via VT82C496G/VT82C570M SMI trigger distinguish:
Bit(s)    Description    (Table P0439)
 7    SMI triggered by primary idle timer time-out
 6    SMI triggered by general purpose timer time-out
 5    SMI triggered by primary activity occurrence
 4    SMI triggered by primary interrupt occurrence
 3    SMI triggered by external pin (Turbo) toggle
 2    (VT82C496G) SMI triggered by DRQ/LREQ occurrence
    (VT82C570M) SMI triggered by DRQ/PREQ occurrence
 1    SMI triggered by peripheral timer or secondary idle timer
      time-out
    (VT82C496G) (use register 65h bits 1 and 0 to distinguish)
 0    SMI triggered by software SMI
SeeAlso: #P0419,#P0438

Bitfields for Via VT82C496G/VT82C570M clock frequency control:
Bit(s)    Description    (Table P0440)
 7-5    (VT82C496G) CPU clock frequency
    000 = CLKIN
    001 = CLKIN / 4
    010 = CLKIN / 8
    011 = CLKIN / 16
    100 = CLKIN / 32
    101 = CLKIN / 64
    110 = CLKIN / 2
    111 = 0
 3-0    CLKIN frequency
    0000 = 16 MHz
    0001 = 40 MHz
    0010 = 50 MHz
    0011 = 80 MHz
    0100 = 66 MHz
    0101 = 100 MHz
    0110 = 8 MHz
    0111 = 60 MHz
    1000 = 8 MHz
    1001 = 20 MHz
    1010 = 25 MHz
    1011 = 40 MHz
    1100 = 33 MHz
    1101 = 50 MHz
    1110 = 4 MHz
    1111 = 30 MHz
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M peripheral timer:
Bit(s)    Description    (Table P0441)
 7-0    (VT82C496G) peripheral timer (time base determined in register 5Dh
      bits 1-0)
    (VT82C570M) peripheral timer (time base determined in register 66h
      bits 3-2)
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M general purpose timer:
Bit(s)    Description    (Table P0442)
 7-0    general purpose timer (time base determined in register 59h bits 7-6)
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M timer control:
Bit(s)    Description    (Table P0443)
 7-6    general purpose timer (register 58h) time base
    00 = disable
    01 = 32.768 KHz
    10 = 1 sec
    11 = 1 min
 3-1    primary idle timer time-out
    000 = disable
    001 = 1 sec
    010 = 8 sec
    011 = 32 sec
    100 = 1 min
    101 = 8 min
    110 = 16 min
    111 = 32 min
 0    (VT82C496G) leakage control mode
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M power/peripheral control:
Bit(s)    Description    (Table P0444)
 7-4    general purpose output ports ???
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M system management control:
Bit(s)    Description    (Table P0445)
 7    (VT82C496G) power management mode enable
 6    (VT82C496G) SMI type
    0 = Intel 2-pin SMI (SMI#/SMIACT#)
      (pin 112 used as SMIACT#, SM base = 30000h to 4FFFFh)
    1 = TI/AMD/Cyrix 3-pin SMI (SMI#/SMIADS#/SMIRDY#)
      (pin 112 used as SMIADS#, SM base = 60000h to 7FFFFh)
 5    (VT82C496G) SMI target
    0 = SMI output to CPU
    1 = SMI redirected to interrupt 15 of internal 8259 interrupt
      controller (for non-SMI CPU support)
 4    SM memory remap enable (SM base memory mapped to A0000h to BFFFFh)
 3    (VT82C496G) direct DRAM access to SMI target memory A0000h-BFFFFh
      enable
 2    ???
 1    (VT82C496G) force 3000h-4FFFFh to map to A0000h-BFFFFh
    (move SM code without causing local bus device conflict with
      A0000h-BFFFFh)
 0    clock throttling enable
SeeAlso: #P0419

Bitfields for Via VT82C496G clock switching control:
Bit(s)    Description    (Table P0446)
 7    wait for a HALT cycle to start clock switching
 6    wait for an acknowledgment to start clock switching
 5    clock switching protocol
    0 = Intel STPCLK# protocol (pin 117 used as STPCLK# output)
    1 = TI/Cyrix SUSP#/SUSPA# protocol (pin 117 used as SUSP# input)
SeeAlso: #P0419

Bitfields for Via VT82C496G peripheral timer control:
Bit(s)    Description    (Table P0447)
 7-2    ???
 1-0    peripheral timer (register 57h) time base
    00 = disable
    01 = 32.768 KHz
    10 = 1 sec
    11 = 1 min
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M misc. cache control:
Bit(s)    Description    (Table P0448)
 7    (VT82C496G) CPU internal cache
    0 = write-through
    1 = write-back
 6    external cache
    0 = write-back
    1 = write-through
 5    (VT82C496G) pin 72 usage
    0 = BLAST# (burst last input from the CPU)
    1 = CACHE# (P24T) (burst cycle indicator)
 4    (VT82C496G) snoop filtering enable
 3    ???
 2    slow refresh enable
 1-0    ???
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M conserve mode/secondary idle timer:
Bit(s)    Description    (Table P0449)
 7-6    (VT82C496G) conserve mode active period
    00 = 1/16 sec
    01 = 1/8 sec
    10 = 1 sec
    11 = 1 min
 5    conserve mode enable
 4    (VT82C496G) conserve mode clock select
    0 = CLKIN / 2
    1 = CLKIN / 4
 3-2    secondary idle timer time-out
    00 = 2 ms
    01 = 16 ms
    10 = 64 ms
    11 = EOI + 0.125 ms
 1    secondary events handler enable (secondary interrupt reloads secondary
      idle timer)
 0    (VT82C496G) change clock speed on secondary interrupt to
    0 = CLKIN
    1 = CLKIN / 2
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M IRQ7-0 primary interrupt selection:
Bit(s)    Description    (Table P0450)
 7    IRQ7 is primary interrupt
 6    IRQ6 is primary interrupt
 5    IRQ5 is primary interrupt
 4    IRQ4 is primary interrupt
 3    IRQ3 is primary interrupt
 2    IRQ1 is primary interrupt
 1    IRQ0 is primary interrupt
 0    (VT82C496G) reload primary idle timer on primary interrupt
SeeAlso: #P0419,#P0451,#P0452

Bitfields for Via VT82C496G/VT82C570M IRQ15-8 primary interrupt selection:
Bit(s)    Description    (Table P0451)
 7    IRQ15 is primary interrupt
 6    IRQ14 is primary interrupt
 5    IRQ13 is primary interrupt
 4    IRQ12 is primary interrupt
 3    IRQ11 is primary interrupt
 2    IRQ10 is primary interrupt
 1    IRQ9 is primary interrupt
 0    IRQ8 is primary interrupt
SeeAlso: #P0419,#P0450,#P0453

Bitfields for Via VT82C496G IRQ7-3 interrupt mode and global control:
Bit(s)    Description    (Table P0452)
 7    IRQ7 interrupt mode (refer to note below)
 6    IRQ6 interrupt mode
 5    IRQ5 interrupt mode
 4    IRQ4 interrupt mode
 3    IRQ3 interrupt mode
 2    IRQ8 treated as
    0 = sub-secondary interrupt (CPU clock speed unchanged)
    1 = secondary interrupt
 1    IRQ0 treated as
    0 = sub-secondary interrupt (CPU clock speed unchanged)
    1 = secondary interrupt
 0    interrupt mode global control
    0 = 8259A compatible mode (all interrupt edge triggered)
    1 = extended mode (enables selection with registers 62h and 63h)
Note:    for bits 7-3, 0 = edge-triggered, 1 = level-sensitive
SeeAlso: #P0419,#P0450,#P0453

Bitfields for Via VT82C496G/VT82C570M IRQ15-9 interrupt mode:
Bit(s)    Description    (Table P0453)
 7    IRQ15 interrupt mode (refer to note below)
 6    IRQ14 interrupt mode
 5    reserved
 4    IRQ12 interrupt mode
 3    IRQ11 interrupt mode
 2    IRQ10 interrupt mode
 1    IRQ9 interrupt mode
 0    ???
Note:    for bits 7-6 and 4-1, 0 = edge-triggered, 1 = level-sensitive
SeeAlso: #P0419,#P0451,#P0452

Bitfields for Via VT82C496G/VT82C570M register 64h:
Bit(s)    Description    (Table P0454)
 3-0    MA0-3 jumper setting ???
SeeAlso: #P0419

Bitfields for Via VT82C496G/VT82C570M peripheral timer control:
Bit(s)    Description    (Table P0455)
 7    reload peripheral timer on keyboard access
 6    reload peripheral timer on serial port access
 5    reload peripheral timer on video access
 4    reload peripheral timer on hard disk and floppy access
 3    (VT82C496G) trigger SMI on peripheral timer time-out
    (VT82C570M) reload peripheral timer on parallel port access
 2    (VT82C496G) trigger SMI on secondary idle timer time-out
    (VT82C570M) reserved
 1    (VT82C496G) SMI triggered by peripheral timer time-out
    (VT82C570M) reload peripheral timer on speaker access
 0    (VT82C496G) SMI triggered by secondary idle timer time-out
    (VT82C570M) reserved
SeeAlso: #P0419

Bitfields for Via VT82C496G IDE controller/cache control:
Bit(s)    Description    (Table P0456)
 7    reserved
 6    channel and I/O port selection
    0 = primary channel (1F0h-1F7h)
    1 = secondary channel (170h-177h)
 5    write buffer enable
 4    prefetch buffer enable
 3    internal LRDY# for write cycles (0 = second T2, 1 = first T2)
 2    internal LRDY# for read cycles    (0 = second T2, 1 = first T2)
 1    read data to be presented to CPU data bus
    0 = second T2
    1 = first T2
 0    internal IDE controller enable
SeeAlso: #P0419

Bitfields for Via VT82C496G non-1F0/170h port access timing:
Bit(s)    Description    (Table P0457)
 7-4    number of CPU clocks as command active time
 3-0    number of CPU clocks as command recovery time
SeeAlso: #P0419

Bitfields for Via VT82C496G drive #0/1 read timing for 1F0/170h access:
Bit(s)    Description    (Table P0458)
 7-4    number of CPU clocks as command active time
 3-0    number of CPU clocks as command recovery time
SeeAlso: #P0419,#P0459,#P0460

Bitfields for Via VT82C496G drive #0/1 write timing for 1F0/170h access:
Bit(s)    Description    (Table P0459)
 7-4    number of CPU clocks as command active time
 3-0    number of CPU clocks as command recovery time
SeeAlso: #P0419,#P0458,#P0460

Bitfields for Via VT82C496G drive #0/1 address setup time:
Bit(s)    Description    (Table P0460)
 1-0    number of CPU clocks as address setup time
SeeAlso: #P0419,#P0458,#P0459
----------P00A800AC--------------------------
PORT 00A8-00AC - Via VT82C570M "Apollo Master" - CONFIGURATION REGISTERS
SeeAlso: PORT 00A8h"VT82C486G"

00A8  ?W  configuration register index (see #P0461)
00A9  RW  configuration register 00h-9Fh data
00AC  RW  configuration register FBh-FFh data

(Table P0461)
Values for Via VT82C570M configuration registers:
 02h    clock throttling control (see #P0420)
 03h    I/O recovery (see #P0421)
 10h    bus speed (see #P0422)
 11h    ISA bus clock frequency control (see #P0423)
 20h    pair 0/1 row/column address (see #P0424)
 21h    pair 2/3 row/column address (see #P0425)
 22h    RAS#/CAS# pulse control (see #P0426)
 30h    C0000h-CFFFFh shadow control (see #P0427)
 31h    D0000h-DFFFFh shadow control (see #P0428)
 32h    E0000h-FFFFFh shadow control (see #P0429)
 33h    ROM decoding and memory relocation (see #P0430)
 40h    ROM cacheable control (see #P0431)
 41h    programmable non-cacheable region ???
 42h    programmable non-cacheable region ???
 43h    pair 0/1 DRAM size and configuration (see #P0432)
 44h    pair 2/3 DRAM size and configuration (see #P0433)
 47h    DRAM type (see #P0462)
 48h    DRAM control (see #P0463)
 49h    cache control (see #P0464)
 50h    cache access mode (see #P0434)
 51h    cache timing/size control (see #P0435)
 52h    primary idle timer reloading control (see #P0436)
 53h    primary idle timer reload distinguish (see #P0437)
 54h    SMI triggering control (see #P0438)
 55h    SMI trigger distinguish (see #P0439)
 56h    clock frequency control (see #P0440)
 58h    general purpose timer (see #P0442)
 59h    timer control (see #P0443)
 5Ah    power/peripheral control (see #P0444)
 5Bh    system management control (see #P0445)
 5Eh    misc. cache control (see #P0448)
 5Fh    conserve mode/secondary idle timer control (see #P0449)
 60h    IRQ7-0 primary interrupt selection (see #P0450)
 61h    IRQ15-8 primary interrupt selection (see #P0451)
 63h    IRQ15-9 interrupt mode (see #P0453)
 64h    (see #P0454)
 65h    peripheral timer control (see #P0455)
 66h    (see #P0465)
 67h    peripheral timer (see #P0441)
 68h    multiple SMI triggering ???
 69h    multiple SMI triggering ???
 6Ah    multiple SMI triggering ???
 7Bh    general purpose input and output port ???
 7Ch    general purpose input and output port ???
 7Eh    general purpose output port ???
 7Fh    general purpose input and output port ???
 82h    PCI buffer control (see #P0466)
 83h    PCI data link control (see #P0467)
 84h    PCI interface timing (see #P0468)
 85h    PCI arbitration (see #P0469)
 86h    (see #P0470)
 93h    (see #P0471)
 9Ch    programmable chipselect A (see #P0472)
 9Dh    programmable chipselect A address mask (see #P0473)
 9Eh    programmable chipselect B (see #P0474)
 9Fh    programmable chipselect B address mask (see #P0475)
 FBh    plug and play DRQ routing (see #P0476)
 FCh    PCI interrupt polarity (see #P0477)
 FDh    plug and play IRQ routing (see #P0478)
 FEh    PCI IRQ routing 1 (see #P0479)
 FFh    PCI IRQ routing 2 (see #P0480)
SeeAlso: #P0419

Bitfields for Via VT82C570M DRAM type:
Bit(s)    Description    (Table P0462)
 7    Bank 3 DRAM type (used with bit 3)
    bits 7 and 3:
    00 = standard DRAM
    01 = burst EDO DRAM
    10 = EDO DRAM
    11 = illegal
 6    Bank 2 DRAM type (used with bit 2)
    bits 6 and 2: same values as for bits 7 and 3
 5    Bank 1 DRAM type (used with bit 1)
    bits 5 and 1: same values as for bits 7 and 3
 4    Bank 0 DRAM type (used with bit 0)
    bits 4 and 0: same values as for bits 7 and 3
 3    Bank 3 DRAM type (used with bit 7)
 2    Bank 2 DRAM type (used with bit 6)
 1    Bank 1 DRAM type (used with bit 5)
 0    Bank 0 DRAM type (used with bit 4)
SeeAlso: #P0461

Bitfields for Via VT82C570M register 48h:
Bit(s)    Description    (Table P0463)
 7    reserved
 6    eight CWE# pins for each byte in addition to global GWE# ???
 5-4    reserved
 3-0    DRAM operation width (if register 20h bit 0 = 1)
    0 = 64 bit operation for corresponding DRAM bank
    1 = 32 bit operation for corresponding DRAM bank
SeeAlso: #P0461

Bitfields for Via VT82C570M register 49h:
Bit(s)    Description    (Table P0464)
 5    0 = cache SRAM write enable for each bank
    1 = cache SRAM byte write enable
SeeAlso: #P0461

Bitfields for Via VT82C570M register 66h:
Bit(s)    Description    (Table P0465)
 3-2    peripheral timer (register 67h) time base
    00 = disable
    01 = 32.768 KHz
    10 = 1 sec
    11 = 1 min
SeeAlso: #P0461

Bitfields for Via VT82C570M PCI buffer control:
Bit(s)    Description    (Table P0466)
 7    CPU to PCI write buffer enable
 6    PCI to memory write buffer enable
 5    reserved
 4    PCI accessing memory prefetch buffer enable
 3    PCI accelerated decoding enable
 2    reserved
 1    on-board memory burst write enable
 0    on-board memory burst read enable
SeeAlso: #P0461

Bitfields for Via VT82C570M PCI data link control:
Bit(s)    Description    (Table P0467)
 7    data link write cycle
    0 = 1 wait state
    1 = 0 wait state
 6-4    reserved
 3    on-board memory detection point for PCI master
    0 = first address phase
    1 = first data phase
 2-1    reserved
 0    reserved (must be 0)
SeeAlso: #P0461

Bitfields for Via VT82C570M PCI interface timing:
Bit(s)    Description    (Table P0468)
 7    slave mode lock function enable
 6    retry count
    0 = 16 times
    1 = 64 times
 5    retry deadlock error reporting enable
 4    retry status occurred (write 1 to reset)
 3    CPU to PCI fast back to back enable
 2    fast FRAME# generation enable
 1-0    DEVSEL# decoding
    00 = fast
    01 = medium
    10 = slow
    11 = subtractive
SeeAlso: #P0461

Bitfields for Via VT82C570M PCI arbitration:
Bit(s)    Description    (Table P0469)
 7    0 = priority on PCI bus
    1 = fairness between CPU and PCI bus
 6    0 = REQ# based
    1 = FRAME# based
 5-4    CPU time slot in unit of
    00 = 4 PCI clocks
    01 = 8 PCI clocks
    10 = 16 PCI clocks
    11 = 32 PCI clocks
 3-0    PCI master bus time out
    0000 = disable
    0001-1111 = 1x32 - 15x32 PCI clocks
SeeAlso: #P0461

Bitfields for Via VT82C570M register 86h:
Bit(s)    Description    (Table P0470)
 7    PCI configuration mechanism #1/#2 (default #1)
SeeAlso: #P0461

Bitfields for Via VT82C570M register 93h:
Bit(s)    Description    (Table P0471)
 5    parity or system error at PCI bus signify
    0 = I/O channel check
    1 = NMI
SeeAlso: #P0461

Bitfields for Via VT82C570M programmable chipselect A:
Bit(s)    Description    (Table P0472)
 7-0    chipselect A address (high two bits in register 9Dh bits 1-0)
SeeAlso: #P0461,#P0473,#P0474

Bitfields for Via VT82C570M programmable chipselect A address mask:
Bit(s)    Description    (Table P0473)
 7-2    chipselect A address mask
 1-0    chipselect A address (low eight bits in register 9Dh)
SeeAlso: #P0461,#P0472,#P0474

Bitfields for Via VT82C570M programmable chipselect B:
Bit(s)    Description    (Table P0474)
 7-0    chipselect B address (high two bits in register 9Fh bits 1-0)
SeeAlso: #P0461,#P0472,#P0475

Bitfields for Via VT82C570M programmable chipselect B address mask:
Bit(s)    Description    (Table P0475)
 7-2    chipselect B address mask
 1-0    chipselect B address (low eight bits in register 9Eh)
SeeAlso: #P0461,#P0473,#P0474

Bitfields for Via VT82C570M plug and play DRQ routing:
Bit(s)    Description    (Table P0476)
 7-6    reserved
 5-3    PDRQ1 routing
    000-011 = DRQ0-3
    100 = reserved
    101-111 = DRQ5-7
 2-0    PDRQ0 routing
    000-011 = DRQ0-3
    100 = reserved
    101-111 = DRQ5-7
SeeAlso: #P0461

Bitfields for Via VT82C570M PCI interrupt polarity:
Bit(s)    Description    (Table P0477)
 7-4    reserved
 3    INTA# polarity (refer to note below)
 2    INTB# polarity
 1    INTC# polarity
 0    INTD# polarity
Note:    for bits 3-0, 0 = non-invert (level-sensitive), 1 = inverted (edge)
SeeAlso: #P0461

Bitfields for Via VT82C570M plug and play IRQ routing:
Bit(s)    Description    (Table P0478)
 7-4    INTD# routing (value indicates desired IRQ number; 0,2,13 are reserved)
 3-0    PIRQ0 routing (value indicates desired IRQ number; 0,2,13 are reserved)
SeeAlso: #P0461,#P0479,#P0480

Bitfields for Via VT82C570M PCI IRQ routing 1:
Bit(s)    Description    (Table P0479)
 7-4    INTA# routing (value indicates desired IRQ number; 0,2,13 are reserved)
 3-0    INTB# routing (value indicates desired IRQ number; 0,2,13 are reserved)
SeeAlso: #P0461,#P0478,#P0480

Bitfields for Via VT82C570M PCI IRQ routing 2:
Bit(s)    Description    (Table P0480)
 7-4    INTC# routing (value indicates desired IRQ number; 0,2,13 are reserved)
 3-0    PIRQ1 routing (value indicates desired IRQ number; 0,2,13 are reserved)
SeeAlso: #P0461,#P0478,#P0479
----------P00A800A9--------------------------
PORT 00A8-00A9 - Via VT82C586A - GPIO

00A8  ?W  configuration register index
00A9  RW  configuration register data
----------P00B000BF--------------------------
PORT 00B0-00BF - PC radio by CoZet Info Systems
Range:    The I/O address range is dipswitch selectable from:
       038-03F and 0B0-0BF
       078-07F and 0F0-0FF
       138-13F and 1B0-1BF
       178-17F and 1F0-1FF
       238-23F and 2B0-2BF
       278-27F and 2F0-2FF
       338-33F and 3B0-3BF
       378-37F and 3F0-3FF
Notes:    All of these addresses show a readout of FFh in initial state.
    Once started, all of the addresses show    FBh, whatever might happen.
----------P00B2------------------------------
PORT 00B2 - Intel chipsets - Advanced Power Management Control
Notes:    used to pass data between the operating system and the System
      Management Interrupt (SMI) handler
    writes to this port can cause an SMI; reads can cause STPCLK# to be
      asserted (putting the CPU in sleep mode)
    supported by 82420EX, 82371, and other Intel chipsets
SeeAlso: PORT 00B3h,#01079

00B2  RW  control
----------P00B3------------------------------
PORT 00B3 - Intel chipsets - Advanced Power Management Status
Notes:    used to pass data between the operating system and the System
      Management Interrupt (SMI) handler
    supported by 82420EX, 82371, and other Intel chipsets
SeeAlso: PORT 00B2h

00B3  RW  status
----------P00C0------------------------------
PORT 00C0 - TI SN746496 programmable tone/noise generator (PCjr)
----------P00C000DF--------------------------
PORT 00C0-00DF - DMA 2 - SECOND DIRECT MEMORY ACCESS CONTROLLER (8237)

00C0  RW  DMA channel 4 memory address bytes 1 and 0 (low) (ISA, EISA)
00C2  RW  DMA channel 4 transfer count bytes 1 and 0 (low) (ISA, EISA)
00C4  RW  DMA channel 5 memory address bytes 1 and 0 (low) (ISA, EISA)
00C6  RW  DMA channel 5 transfer count bytes 1 and 0 (low) (ISA, EISA)
00C8  RW  DMA channel 6 memory address bytes 1 and 0 (low) (ISA, EISA)
00CA  RW  DMA channel 6 transfer count bytes 1 and 0 (low) (ISA, EISA)
00CC  RW  DMA channel 7 memory address byte 0 (low), then 1 (ISA, EISA)
00CE  RW  DMA channel 7 transfer count byte 0 (low), then 1 (ISA, EISA)

00D0  R-  DMA channel 4-7 status register (ISA, EISA) (see #P0481)
00D0  -W  DMA channel 4-7 command register (ISA, EISA) (see #P0482)
00D2  -W  DMA channel 4-7 write request register (ISA, EISA)
00D4  -W  DMA channel 4-7 write single mask register (ISA, EISA) (see #P0484)
00D6  -W  DMA channel 4-7 mode register (ISA, EISA) (see #P0485)
00D8  -W  DMA channel 4-7 clear byte pointer flip-flop (ISA, EISA)

00DA  R-  DMA channel 4-7 read temporary register (ISA, EISA)
00DA  -W  DMA channel 4-7 master clear (ISA, EISA)
00DC  -W  DMA channel 4-7 clear mask register (ISA, EISA)
00DE  -W  DMA channel 4-7 write mask register (ISA, EISA) (see #P0486)
Notes:    the temporary register is used as holding register in memory-to-memory
      DMA transfers; it holds the last transferred byte
    channel 4 is used for cascading the first (8-bit) DMA controller
    base/current address registers can only address the memory in 16-bit
      words (i.e. they contain lines A1-A16 of the address bus with line
      A0 always equal to 0); base/current word count registers contain the
      number of 16-bit words
    command and request registers do not exist on PS/2 DMA controller

Bitfields for DMA channel 4-7 status register:
Bit(s)    Description    (Table P0481)
 7 = 1    channel 7 request
 6 = 1    channel 6 request
 5 = 1    channel 5 request
 4 = 1    channel 4 request
 3 = 1    terminal count on channel 7
 2 = 1    terminal count on channel 6
 1 = 1    terminal count on channel 5
 0 = 1    terminal count on channel 4
SeeAlso: #P0001,#P0482

Bitfields for DMA channel 4-7 command register:
Bit(s)    Description    (Table P0482)
 7    DACK sense active high
 6    DREQ sense active high
 5    =1  extended write selection
    =0  late write selection
 4    rotating priority instead of fixed priority
 3    compressed timing
 2    =1  enable controller
    =0  enable memory-to-memory transfer
 1-0    channel number (00 = 4 to 11 = 7)
SeeAlso: #P0002,#P0481,#P0484

Bitfields for DMA channel 4-7 request register:
Bit(s)    Description    (Table P0483)
 7-3    reserved (0)
 2    =0 clear request bit
    =1 set request bit
 1-0    channel number
    00 channel 4 select
    01 channel 5 select
    10 channel 6 select
    11 channel 7 select
SeeAlso: #P0003,#P0484

Bitfields for DMA channel 4-7 write single mask register:
Bit(s)    Description    (Table P0484)
 7-3    reserved
 2    =0  clear mask bit
    =1  set mask bit
 1-0    channel select
    00 channel 4 select
    01 channel 5 select
    10 channel 6 select
    11 channel 7 select
SeeAlso: #P0004,#P0482

Bitfields for DMA channel 4-7 mode register:
Bit(s)    Description    (Table P0485)
 7-6    transfer mode
    00  demand mode
    01  single mode
    10  block mode
    11  cascade mode
 5    direction
    0  address increment select
    1  address decrement select
 4    autoinitialisation enabled
 3-2    operation
    00  verify operation
    01  write to memory
    10  read from memory
    11  reserved
 1-0    channel number
    00  channel 4 select
    01  channel 5 select
    10  channel 6 select
    11  channel 7 select
SeeAlso: #P0005,#P0484

Bitfields for DMA channel 4-7 write mask register:
Bit(s)    Description    (Table P0486)
 7-4    reserved
 3    channel 7 mask bit
 2    channel 6 mask bit
 1    channel 5 mask bit
 0    channel 4 mask bit
Note:    each mask bit is automatically set when the corresponding channel
      reaches terminal count or an extenal EOP sigmal is received
SeeAlso: #P0484,#P0006
----------P00E000E1--------------------------
PORT 00E0-00E1 - CHIPSET FROM ACT

00E0  ?W  index for accesses to data port
00E1  R?  chip set data
----------P00E000E7--------------------------
PORT 00E0-00E7 - MICROCHANNEL

00E0  RW  split address register, memory encoding registers PS/2m80 only
    (see #P0487)
00E1  RW  memory register (see #P0488,#P0489)
00E3  RW  error trace (bits 23-16 of address on last rising edge of ERS line)
00E4  RW  error trace (bits 15-8 of address on last rising edge of ERS line)
00E5  RW  error trace (see #P0490)
00E7  RW  error trace (see #P0491)

Bitfields for Microchannel Split Address Register:
Bit(s)    Description    (Table P0487)
 7-6    unused
 5-4    2MB memory for connector 2 on Type2 motherboard
    bit 5: second MB disabled or not present
    bit 4: first MB disabled or not present
 3-0    address at which to place leftover from split in first MB, in MB
    (1-15, 0 is invalid when split is active)
SeeAlso: #P0488,#P0489

Bitfields for Microchanel Memory Register, Type1 motherboard:
Bit(s)    Description    (Table P0488)
 7-6    1 MB memory for connector 2
    10 installed
    11 not installed
 5-4    1 MB memory for connector 1
    10 installed
    11 not installed
 3-1    split memory select
        ROM   convmem    over1M
    001    ON    640K    384K
    011    ON    512K    512K
    100    shadow    640K    0K
    101    ON    640K    0K
    110    shadow    512K    0K
    111    ON    512K    0K
 0    parity checking
    =0 enable
    =1 clear parity error (write 0 to re-enable parity checking)
SeeAlso: #P0487,#P0489

Bitfields for Microchannel Memory Register, Type2 motherboard:
Bit(s)    Description    (Table P0489)
 7-6    unused
 5-4    memory connector 1
    bit 5: second MB disabled or not present
    bit 4: first MB disabled or not present
 3-1    split memory select
        ROM   convmem    over1M
    000    shadow    640K    256K
    001    ON    640K    384K
    010    shadow    512K    384K
    011    ON    512K    512K
    100    shadow    640K    0K
    101    ON    640K    0K
    110    shadow    512K    0K
    111    ON    512K    0K
 0    parity checking
    =0 enable
    =1 clear parity error (write 0 to re-enable parity checking)
SeeAlso: #P0487,#P0488

Bitfields for Microchannel Error Trace register E5h:
Bit(s)    Description    (Table P0490)
 7-2    bits 7-2 of address on last rising edge of ERS line
 1    address space (0=I/O, 1=memory)
 0    =1 bus-master arbitration cycle
SeeAlso: #P0491

Bitfields for Microchannel Error Trace register E7h:
Bit(s)    Description    (Table P0491)
 7-1    unused
 0    bus cycle type
    =0 control (instruction fetch, halt, interrupt acknowledge)
    =1 data
SeeAlso: #P0490
----------P00E000EF--------------------------
PORT 00E0-00EF - IBM PS/1 CLOCK
----------P00E1------------------------------
PORT 00E1 - STB PowerMEG - ???
Desc:    the STB PowerMEG is a memory expansion card capable of providing EMS

00E1  RW  ???
      bit 0: ???
--------X-P00E2------------------------------
PORT 00E2 - S3 Trio64V+ - I2C PORT
Range:    PORT 00E2h or PORT 00E8h; default depends on external pin, but can
      be reprogrammed via chip's CR6F
SeeAlso: PORT 00E8h,#M0079
--------X-P00E8------------------------------
PORT 00E8 - S3 Trio64V+ - I2C PORT
Range:    PORT 00E2h or PORT 00E8h; default depends on external pin, but can
      be reprogrammed via chip's CR6F
SeeAlso: PORT 00E2h,#M0079
----------P00EB------------------------------
PORT 00EB - Intel "Triton" chipset - ???
SeeAlso: PORT 0085h"Triton"

00EB  ?W  ???
----------P00EB------------------------------
PORT 00EB - DUMMY PORT FOR DELAY???
Note:    on a number of machines, the BIOS appears to write a copy of any
      data sent to numerous other ports to this port as well; it seems
      to be a dummy port used for short delays between writes to other
      ports (used instead of JMP $+2, which no longer delays on Pentium+)
SeeAlso: PORT 00ED"DUMMY"

00EB  ?W  ???
----------P00EC00ED--------------------------
PORT 00EC-00ED - Compaq LTE Elite
----------P00ED------------------------------
PORT 00ED - DUMMY PORT FOR DELAY???
Note:    on a number of machines, the BIOS appears to write a copy of any
      data sent to numerous other ports to this port as well; it seems
      to be a dummy port used for short delays between writes to other
      ports (used instead of JMP $+2, which no longer delays on Pentium+)
SeeAlso: PORT 00EB"DUMMY"

00EDw  ?W  ???
----------P00EF------------------------------
PORT 00EF - Hyunday Super-NB386S (AMD386sx with Intel chipset)
Warning: any access to this port causes a cold reset on this machine!
----------P00F000F5--------------------------
PORT 00F0-00F5 - PCjr Disk Controller

00F0  ??  disk controller
00F2  ??  disk controller control port
00F4  ??  disk controller status register
00F5  ??  disk controller data port
----------P00F000FF--------------------------
PORT 00F0-00FF - MATH COPROCESSOR (8087..80387)

00F0  -W  math coprocessor clear busy latch (write 00h)
00F1  -W  math coprocessor reset (write 00h)
00F8  RW  opcode transfer (CPU-coprocessor communication)
00FA  RW  opcode transfer
00FC  RW  opcode transfer
----------P00F9------------------------------
PORT 00F9 - Compaq LTE Elite
----------P00FB------------------------------
PORT 00FB - Compaq LTE Elite
----------P00F900FF--------------------------
PORT 00F9-00FF - PC radio by CoZet Info Systems
Range:    The I/O address range is dipswitch selectable from:
       038-03F and 0B0-0BF
       078-07F and 0F0-0FF
       138-13F and 1B0-1BF
       178-17F and 1F0-1FF
       238-23F and 2B0-2BF
       278-27F and 2F0-2FF
       338-33F and 3B0-3BF
       378-37F and 3F0-3FF
Notes:    All of these addresses show a readout of FFh in initial state.
    Once started, all of the addresses show    FBh, whatever might happen.
----------P0100------------------------------
PORT 0100 - 3COM 3C509 Ethernet card - ID port
Note: this port is present only on the 3C509, not on any other 3COM card
SeeAlso: PORT 0110h,PORT 0120h
----------P01000107--------------------------
PORT 0100-0107 - PS/2 POS (Programmable Option Select)
Note:    the default value for PORT 0102h is stored in CMOS 31h

0100  R      POS register 0    Low adapter ID byte
0101  R      POS register 1    High adapter ID byte
0102  RW  POS register 2    option select data byte 1 (see #P0492)
0103  RW  POS register 3    option select data byte 2 (see #P0493)
0104  RW  POS register 4    option select data byte 3
0105  RW  POS register 5    option select data byte 4
         bit 7    channel active (-CHCK)
         bit 6    channel status
0106  RW  POS register 6    Low subaddress extension
0107  RW  POS register 7    High subaddress extension

Bitfields for PS/2 POS register 2, option select data byte 1:
Bit(s)    Description    (Table P0492)
 7      0  = unidirectional LPT port
      1  = bidirectional LPT port
 6-5    PS/2 Model 50 and higher
     00b = default LPT port at 3BCh
     01b = ""           378h
     10b = ""           278h
     11b = reserved
 4    enable parallel port
 3    serial port address
    =0 COM2 (02F8h, IRQ3)
    =1 COM1 (03F8h, IRQ4)
 2    enable serial port
 1    enable diskette controller
 0    (MCA) =0 override bits 1,2,4 and disable devices
 0    card enable (CDEN)
 0    =1 VGA sleep bit, disconnects output drivers from VGA (usage for VGA
      without monitor)
---ET4000---
 7-4    reserved???
 3    video RAM wait enable
 2    ET4000: ROM BIOS wait enable
 1    ET4000: I/O wait enable
Note:    access to this port is only possible when PORT 0094h bit 7 is low.
SeeAlso: #P0493

Bitfields for Chips&Technologies 64200 "Wingine" setup register:
Bit(s)    Description    (Table P0493)
 7    enable access to extended registers (see #P0762)
Note:    on some C&T graphics chips, this register can be made read-only
      via XR70 (see #P0762)
SeeAlso: #P0492
----------P0100010F--------------------------
PORT 0100-010F - CompaQ Tape drive adapter. alternate address at 0300
----------P0102------------------------------
PORT 0102 - Chips & Technologies 64310 - GLOBAL ENABLE REGISTER
SeeAlso: PORT 0106"Chips"

0102  RW  global enable register (see #P0494)

Bitfields for Chips & Technologies 64310 global enable register:
Bit(s)    Description    (Table P0494)
 7-1    reserved (0)
 0    VGA sleep (used if port 102h bit 1 = 0)
    0 = VGA disabled
    1 = VGA enabled
Note:    Only accessible in setup mode (port 46E8h bit 4 = 1).
SeeAlso: #P0495,#P0492
----------P0106------------------------------
PORT 0106 - Chips & Technologies 64310 - MOTHERBOARD DISABLE REGISTER
SeeAlso: PORT 0102"Chips"

0106  RW  motherboard disable register (see #P0495)

Bitfields for Chips & Technologies 64310 motherboard disable register:
Bit(s)    Description    (Table P0495)
 7-2    reserved (0)
 1    sleep control
    0 = port 102h bit 0 controls VGA sleep (default)
    1 = port 106h bit 0 controls VGA sleep
 0    VGA sleep (used if bit 1 = 1)
    0 = VGA disabled
    1 = VGA enabled
Note:    Only accessible in setup mode (port 46E8h bit 4 = 1),
      if XR01 bit 2 = 1.
SeeAlso: #P0494
----------P0108010F--------------------------
PORT 0108-010F - IBM PS/2 - 8 digit LED info panel

010F  -W  leftmost character on display
010E  -W  second character
 ...
0108  -W  eighth character
----------P0110------------------------------
PORT 0110 - 3COM 3C509 Ethernet card - ID port (alternate address)
Note:    this port is present only on the 3C509, not on any other 3COM card
SeeAlso: PORT 0100h"3COM",PORT 0120h"3COM"
----------P0120------------------------------
PORT 0120 - 3COM 3C509 Ethernet card - ID port (alternate address)
Note:    this port is present only on the 3C509, not on any other 3COM card
SeeAlso: PORT 0100h"3COM",PORT 0110h"3COM"
----------P0130013F--------------------------
PORT 0130-013F - CompaQ SCSI adapter. alternate address at 0330
----------P01300133--------------------------
PORT 0130-0133 - Adaptec 154xB/154xC SCSI adapter
Range:    four ports at any of 0130, 0134, 0230, 0234, 0330 (default) or 0334
----------P01340137--------------------------
PORT 0134-0137 - Adaptec 154xB/154xC SCSI adapter
Range:    four ports at any of 0130, 0134, 0230, 0234, 0330 (default) or 0334
----------P0138013F--------------------------
PORT 0138-013F - PC radio by CoZet Info Systems
Range:    The I/O address range is dipswitch selectable from:
       038-03F and 0B0-0BF
       078-07F and 0F0-0FF
       138-13F and 1B0-1BF
       178-17F and 1F0-1FF
       238-23F and 2B0-2BF
       278-27F and 2F0-2FF
       338-33F and 3B0-3BF
       378-37F and 3F0-3FF
Notes:    All of these addresses show a readout of FFh in initial state.
    Once started, all of the addresses show    FBh, whatever might happen.
---------------------------------------------