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- Apple II
- Technical Notes
- _____________________________________________________________________________
- Developer Technical Support
-
- Apple IIgs
- #30: Apple IIgs Hardware Reference Updates
-
- Revised by: Jim Luther & Rilla Reynolds May 1990
- Written by: Rilla Reynolds October 1987
-
- This Technical Note includes updates to the Apple IIgs Hardware Reference,
- published by Addison-Wesley. Please contact Apple II Developer Technical
- Support at the address listed in Apple II Technical Note #0 if you have
- additional corrections or suggestions for these manuals.
- Changes since March 1990: Documented the Control Panel Control Jumper (S1)
- input to the ADB Microcontroller on page 148 of the Second Edition.
- _____________________________________________________________________________
-
- There are two editions of the Apple IIgs Hardware Reference, the first edition
- (July 1987) which covers the original Apple IIgs only, and the second edition
- (1989) which covers both original Apple IIgs and the 1 MB Apple IIgs. Because
- page numbers have changed between the two editions and because an update to
- one edition may not be needed in both editions, this Technical Note is divided
- into two sections; one for each edition of the manual.
-
-
- Second Edition (1989) Updates
-
- Chapter 3: Memory
-
- Page 40, Table 3-2, Bits in the State register: Switch the given values
- and descriptions for bits 7 and 2 as follows:
-
- Bit Value Description
- _____________________________________________________________________________
- 7 1 ALTZP: If this bit is 1, then bank-switched memory, stack,
- and direct page are in auxiliary memory.
- 0 If this bit is 0, then bank-switched memory, stack, and
- direct page are in main memory.
- 2 1 LCBNK2: If this bit is 1, language-card RAM bank 2 is
- selected.
- 0 If this bit is 0, language-card RAM bank 1 is selected.
-
- Chapter 6: The Apple Desktop Bus
-
- Page 148, after final paragraph: Add a new heading and description:
-
- Control Panel Control Jumper
-
- The ADB microcontroller provided with the 1 MB Apple IIgs includes an
- input that disables the text Control Panel (normally available via the
- Classic Desk Accessory menu). This feature allows the system parameters
- to be set and then protected from changes made via the text Control
- Panel. A jumper across the pins of connector S1 removes the text
- Control Panel from the Classic Desk Accessory menu. All other installed
- classic desk accessories are still available in the Classic Desk
- Accessory menu when the S1 jumper is installed. The S1 connector is
- located near the ADB microcontroller at motherboard location F12.
-
- Note: The S1 jumper does not prevent the system parameters from
- being changed with the graphic Control Panel (a new desk
- accessory normally available from the Apple menu of the
- Finder or of any other application that includes the Apple
- menu).
-
- Chapter 7: Built-in I/O Ports and Clock
-
- Page 154, Table 7-3, Disk-port soft switches:
- $C0EA Drive 1 select
- $C0EB Drive 2 select
-
- In addition to the corrections listed for Table 7-3, the reference to
- "spindle motor switches" in the paragraph following the table should be
- replaced with "drive enable switches."
-
- Page 155, Table 7-4, IWM states: Change the table to this:
-
- Q7 Q6 Drive Operation
- _____________________________________________________________________________
- 0 0 enabled Read Data register
- 0 1 - Read Status register
- 1 0 - Read Handshake register
- 1 1 disabled Write Mode register
- 1 1 enabled Write Data register
- _____________________________________________________________________________
- 1 = asserted state 0 = negated state - = do not care
-
- Pages 156, Table 7-5, Bits in the Mode register: Change the description
- for bit 2, value 0 as follows:
-
- Bit Value Description
- _____________________________________________________________________________
- 2 1 1-second timer is not selected.
- 0 1-second timer selected. When the current disk drive is
- deselected, the drive will remain enabled for 1 second if
- this bit is clear.
-
-
- First Edition (July 1987) Updates
-
- Chapter 3: Memory
-
- Page 36, Table 3-2, Bits in the State register: Switch the given values
- and descriptions for bits 7 and 2 as follows:
-
- Bit Value Description
- _____________________________________________________________________________
- 7 1 ALTZP: If this bit is 1, then bank-switched memory, stack,
- and direct page are in auxiliary memory.
- 0 If this bit is 0, then bank-switched memory, stack, and
- direct page are in main memory.
- 2 1 LCBNK2: If this bit is 1, language-card RAM bank 2 is
- selected.
- 0 If this bit is 0, language-card RAM bank 1 is selected.
-
- Chapter 6: The Apple Desktop Bus
-
- Page 130, Table 6-9, Command byte syntax: The first row in the table
- should read:
-
- x x x x 0 0 0 0 Send Reset
-
- and not
-
- A3 A2 A1 A0 0 0 0 0 Device Reset
-
- Page 131, Device Reset: Replace "Device Reset" with "Send Reset." The
- paragraph should be: "When a device receives a Send Reset command, it will
- clear all pending operations and data, and will initialize to the power-on
- state. The Send Reset command is not device-specific; it is sent to all
- devices simultaneously."
-
- Pages 138-139, Collision detection: The fourth sentence in the last
- paragraph should be: "By using the Listen register 3 command, the host can
- move the device with the activator pressed."
-
- Chapter 7: Built-in I/O Ports and Clock
-
- Page 146, Table 7-3, Disk-port soft switches:
- $C0E8 Drive disabled
- $C0E9 Drive enabled
- $C0EA Drive 1 select
- $C0EB Drive 2 select
-
- In addition to the corrections listed for Table 7-3, the reference to
- "spindle motor switches" in the paragraph following the table should be
- replaced with "drive enable switches."
-
- Page 146, Table 7-4, IWM states: Change the table to this:
-
- Q7 Q6 Drive Operation
- _____________________________________________________________________________
- 0 0 enabled Read Data register
- 0 1 - Read Status register
- 1 0 - Read Handshake register
- 1 1 disabled Write Mode register
- 1 1 enabled Write Data register
- _____________________________________________________________________________
- 1 = asserted state 0 = negated state - = do not care
-
- The following text and table should also be added:
-
- "The drive enable switches and the drive select switches control the state
- of the disk port signals DR1 and DR2. The following table shows the
- relationship between these."
-
- Soft Switches | Disk Port Signals
- $C0E8 $C0E9 $C0EA $C0EB | DR1 DR2
- ______________________________________|______________________________________
- 1 - - - | 0 0
- - 1 1 - | 1 0
- - 1 - 1 | 0 1
- ______________________________________|______________________________________
- 1 = asserted state 0 = negated state - = do not care
-
- Page 147, The Mode register: The IWM Mode register is a write-only
- register, so disregard the advice to use only a read-modify-write
- instruction sequence when manipulating bits.
-
- Pages 147-8, Table 7-5, Bits in the Mode register: Switch the given values
- and descriptions for bits 1, 2, and 4 as follows:
-
- Bit Value Description
- _____________________________________________________________________________
- 4 1 8-MHz read-clock speed selected.
- 0 7-MHz read-clock speed selected. Set to 0 for all Apple
- IIGS disk accesses.
- 2 1 1-second timer is not selected.
- 0 1-second timer selected. When the current disk drive is
- deselected, the drive will remain enabled for 1 second if
- this bit is clear.
- 1 1 Asynchronous handshake protocol selected; for all except
- 5.25-inch Apple disk drives.
- 0 Synchronous handshake protocol selected; for 5.25-inch Apple
- disk drives.
-
- Chapter 8: I/O Expansion Slots
-
- Page 167, Direct memory access: DMA bank register location is $C037.
-
-
- Further Reference:
- _____________________________________________________________________________
- o Apple IIGS Hardware Reference, First and Second Editions
-
-