CP/M/CPM_CDROM.iso/simtel/sigm/vols000/vol074/h2651.asm

Assembly Source File | 1984-04-29 | 9.5 KB | 343 lines

;------------------------------------------------------------------------------
;
;    "HITE" Hardware Dependant Code Module for "2651" Family UARTS
;
;        Version 1.0 , March 10, 1982 - By Software Tools
;
;------------------------------------------------------------------------------
;
;    By    Bill Bolton
;        Software Tools,
;        P.O. Box 80,
;        Newport Beach,
;        NSW, 2106
;        AUSTRALIA
;
    TITLE    '2651 UART Interface for HITE, Software Tools'
;
;DESCRIPTION:
;
;    This code is generally applicable to any 2561 based port. Conditional
;    assembly options are available for bank selected type ports such as
;    found on the Godbout Interfacer 3 IEEE-696 card. The code has been
;    extensively tested on both Godbout System Support and Interfacer 3
;    Cards. The code as presented here is set up for assembly with the
;    MAC or MACRO-80 assemblers. If you wish to assemble it with ASM the
;    'TITLE' line must be removed and the 'hexnum' macro must be eliminated
;    and the port numbers in the signon message must be expanded by hand
;    (i.e. you'll have to plug the ASCII values for the port addresses
;    into the message yourself).
;
;    See the additional notes near the INIT, EXIT and HEXNUM routines.
;
;************************************************
;*                        *
;*         Miscellaneous Equates        *
;*                        *
;************************************************
;
TRUE    EQU    0FFFFH
FALSE    EQU    NOT TRUE

BDOS    EQU    0005            ;CP/M BDOS entry point
ALF    EQU    0AH            ;ASCII line feed
ACR    EQU    0DH            ;ASCII carriage return
;
;************************************************
;*                        *
;*         2651 Baud Rate Table        *
;*                        *
;************************************************
;
B50    EQU    0000B            ;50 bps
B75    EQU    0001B            ;75 bps
B110    EQU    0010B            ;110 bps
B134    EQU    0011B            ;134.5 bps
B150    EQU    0100B            ;150 bps
B300    EQU    0101B            ;300 bps
B600    EQU    0110B            ;600 bps
B1200    EQU    0111B            ;1200 bps
B1800    EQU    1000B            ;1800 bps
B2000    EQU    1001B            ;2000 bps
B2400    EQU    1010B            ;2400 bps
B3600    EQU    1011B            ;3600 bps
B4800    EQU    1100B            ;4800 bps
B7200    EQU    1101B            ;7200 bps
B9600    EQU    1110B            ;9600 bps
B19200    EQU    1111B            ;19200 bps
;
;************************************************
;*                        *
;*        2651 Equates            *
;*                        *
;************************************************
;
BASE    EQU    5CH            ;UART base register
DATA    EQU    BASE+0            ;Data port
STATUS    EQU    BASE+1            ;Status port
MODE    EQU    BASE+2            ;Mode register
CMMD    EQU    BASE+3            ;Command register
USER    EQU    BASE+7            ;User select port
UNUM    EQU    6            ;Modem user number
MODE1    EQU    01101110B        ;Asynch,16x,8 data bits,
                    ; no parity, even, 1 stop bit
MODE2    EQU    01110000B + B300    ;Baud rate
CMMDB    EQU    00100111B        ;Tx enabled, RX enabled, no break
                    ; DTR high, RTS high
ERESET    EQU    CMMDB+8            ;Error reset
;
SYSSPT    EQU    TRUE            ;True for Godbout system support
INTER3    EQU    NOT SYSSPT        ;True for Godbout Interfacer 3
;
;
;------------------------------------------------------------------------------
;
        ORG    108H
SDRIVE:
    DB    0        ;SET NON-ZERO FOR SINGLE DRIVE SITE.
BEEP:
    DB    0        ;SET NON-ZERO TO BEEP WHEN DONE.
TIMEOUT:
    DB    6        ;COUNT-DOWN VALUE FOR TIMEOUT (ABOUT 30 SECS.)
                ;WITH A 4MHZ Z80, 1 = 5 SEC. (SORT OF).
                ;    HENCE ZERO = 21.25 MINUTES.
                ;THE SELECTED VALUE IS A TRADE-OFF, SINCE A LOW
                ;VALUE MAY TIME-OUT WHILE THE RECEIVER IS
                ;WRITING TO DISC (WHICH DOES NO HARM BUT CLOGGS
                ;UP THE SCREEN WITH DISPLAYS) AND A HIGH VALUE
                ;CAUSES THE KEYBOARD TH BE CHECKED LESS OFTEN.
                ;
;------------------------------------------------------------------------------
;
;
HINIT:        JMP    INIT        ;UART/USART INITIALATION ENTRY POINT
HEXIT:        JMP    EXIT        ;SPECIAL USER EXIT ROUTINE
HSTAT:        JMP    STAT        ;STATUS PORT READ ENTRY POINT
HRES:        JMP    RES        ;UART/USART ERROR RESET ENTRY POINT
HRX:        JMP    RX        ;READ DATA PORT ENTRY POINT
HTX:        JMP    TX        ;WRITE DATA PORT ENTRY POINT
;
;
;------------------------------------------------------------------------------
;            THIS IS THE UART/USART INITIALISATION ROUTINE.
;            TO ENSURE COMPATIBILITY WITH OTHER USERS, THE
;            FOLLOWING STANDARD IS RECCOMENDED :
;            1. USE 1 STOP BIT    (OPTIONAL - 2)
;            2. USE 8 DATA BITS    (MANDATORY)
;            3. USE 1 START BIT    (MANDATORY)
;            4. USE ASYNC MODE ONLY    (MANDATORY)
;
;            For the 2651, the UART operating parameters
;            (which are under software control) are read and stored.
;            On exit from HITE these    entry paramters will be
;            restored to the UART. This allows HITE to
;            transparently use different UART parameters from
;            other programs that may utilise the port.
;
INIT:

    if    inter3
    MVI    A,UNUM
    OUT    USER        ;Select UART
    endif    ;inter3

    IN    MODE        ;Get first mode byte from entry format
    STA    SMODE1        ;Save for exit
    IN    MODE        ;Get second mode byte
    STA    SMODE2        ;Save for exit
    IN    CMMD        ;Get command byte
    STA    SCMMDB        ;Save for exit
INIT1:
    MVI    A,MODE1        ;Put first mode word for HITE format
    OUT    MODE
    MVI    A,MODE2        ;Put second mode word
    OUT    MODE
    MVI    A,CMMDB        ;Put command byte
    OUT    CMMD
SIGNON:
    LXI    D,MESSGE    ;Message is at the end of this module
    MVI    C,9        ;BDOS display string command
    JMP    BDOS        ;Announce version to user and return
                ;to HITE via BDOS RET instruction
;
SMODE1    DB    0        ;Storage for first entry mode byte
SMODE2    DB    0        ;Storage for second entry mode word
SCMMDB    DB    0        ;Storage for entry command byte
;
;------------------------------------------------------------------------------
;            THIS SECTION IS INCLUDED FOR ANY "SPECIAL" USER
;            EXIT CODE. (EG. RESTORING INTERRUPT VECTORS).
;            IF UNUSED, A <RETURN> IS THE ONLY CODE NEEDED.
;            AS THIS IS THE LAST ROUTINE OBEYED BEFORE THE TEST
;            FOR "SINGLE DRIVE SITES" IS MADE, NO REGISTERS NEED
;            TO BE PRESERVED.
;
;
;            For the 2651, the UART operating parameters
;            (entry parameters) will be restored to the UART.
;            This allows HITE to transparently use different
;            UART parameters from other programs that may utilise
;            the port. This is particularly     handy if the same
;            port has to double for another function such as a
;            printer port etc. It is also useful if a dedicated
;            communications port must use different parameters
;            (i.e number of stop bits) when communicating with
;            a variety of other computers in text or binary
;            modes.
;
EXIT:
    LDA    SMODE1        ;Get first mode byte of entry format
    OUT    MODE
    LDA    SMODE2        ;Get second mode byte of entry format
    OUT    MODE
    LDA    SCMMDB        ;Get command byte of entry format
    JMP    RES        ;Do an error reset
;
;
;------------------------------------------------------------------------------
;            THIS IS THE STATUS READ PORT ROUTINE.
;            IT MUST EMULATE THE STATUS BITS FOR
;            AN 8251 USART. I.E.
;
;            BIT 00 SET IF TRANSMITTER READY
;            BIT 01 SET IF RECEIVER READY
;            BIT 02 SET IF TRANSMITTER EMPTY
;            BIT 03 SET IF PARITY  ERROR
;            BIT 04 SET IF OVERRUN ERROR
;            BIT 05 SET IF FRAMING ERROR
;            BITS 06 AND 07 RESET (I.E. 0)
;
;    *** NOTE: ONLY THE "A" REGISTER SHOULD BE ALTERED. ***
;
;
STAT:
    if    inter3
    MVI    A,UNUM
    OUT    USER        ;Select UART
    endif    ;inter3

    IN    STATUS        ;Get status
    ORI    4        ;Force Tx empty high
    RET
;
;
;------------------------------------------------------------------------------
;            THIS IS THE ERROR RESET FOR UART/USART ROUTINE.
;            IF YOUR UART/USART DOES NOT NEED TO BE RESET ON
;            ERROR, WE RECCOMEND THAT YOU DO AN "IN DATA" TO
;            CLEAR THE AIR AND RETURN.
;
RES:
    if    inter3
    MVI    A,UNUM
    OUT    USER        ;Select UART
    endif    ;inter3

    MVI    A,ERESET    ;Reset error flags in 2651
    OUT    CMMD
    MVI    A,CMMDB        ;Restore normal operation
    OUT    CMMD
    RET
;
;
;------------------------------------------------------------------------------
;            THIS IS THE RECEIVE DATA ROUTINE.
;            BEFORE THIS ROUTINE IS ENTERED BIT 02 OF THE
;            STATUS READ ROUTINE MUST HAVE BEEN SET.
;            DO NOT CLEAR THE TOP (MOST SIGNIFICANT) BIT.
;            RETURN WITH REGISTER A LOADED WITH INPUT DATA.
;
;
;
RX:
    if    inter3
    MVI    A,UNUM
    OUT    USER        ;Select UART
    endif    ;inter3

    IN    DATA        ;Get data
    RET
;
;
;
;------------------------------------------------------------------------------
;            THIS IS THE TRANSMIT DATA ROUTINE.
;            BEFORE THIS ROUTINE IS ENTERED BIT 00
;            AND  BIT 3 OF STATUS READ MUST BE SET.
;            DO NOT CLEAR THE TOP BIT BEFORE OUUDATUT.
;            REGISTER A CONTAINS THE DATA.
;
TX:
    if    inter3
    PUSH    PSW
    MVI    A,UNUM
    OUT    USER        ;Select UART
    POP    PSW
    endif    ;inter3

    OUT    DATA        ;Send data
    RET
;
;
;
;------------------------------------------------------------------------------
;
;            THE PURPOSE OF THIS MEASSGE IS TO SHOW
;            (OR REMIND) YOU OF THE ACTUAL HARDWARE
;            THAT THIS VERSION OF HITE IS SET UP FOR.
;
;            Note that only one level of the stack
;            is used on entry to the initialisation routine.
;            The rest of the "reserved" stack space
;            may be used for the signon message as this is only
;            needed once near the start of HITE. Once the message
;            has been displayed it can be safely overwritten by
;            the stack.
;
;
HEXNUM    macro    num
    if    (num/16) > 9
    db    (num/16 and 0fh) + 'A' - 10
    else
    db    (num/16 and 0fh) + '0'
    endif
    if    (num and 0fh) > 9
    db    (num and 0fh) + 'A' - 10
    else
    db    (num and 0fh) + '0'
    endif
    endm

MESSGE:    DB    ACR,ALF,ALF
    DB    'For 2651 UART'

    if    sysspt
    DB    ' on System Support 1 Board'
    endif    ;sysspt

    if    inter3
    DB    ' on Interfacer 3 Board'
    endif    ;sysspt

    DB    ',',ACR,ALF
    DB    'at port '
    hexnum    %BASE
    DB    'H, 300 bps, 1 stop, no parity.',ACR,ALF

    if    inter3
    DB    'UART Offset '
    hexnum    %UNUM
    DB    ', '
    endif    ;inter3

    DB    'Version 1.0, 10/May/82',ACR,ALF
    DB    '$'
;
;
;
;
;------------------------------------------------------------------------------
;
;
    END