Jumper settings
During the evolution of the ATW800/2 the jumpers on the card were sometime (re)used in a different way depending on the card-revision and installed CPLD firmware. This was done to guarantee backwards compatibility for earlier card revisions when upgraded with a newer firmware.
The Mk3 V1.1 PCB introduced an additional jumper which can only be used when plugged into a Mega-ST. Here's a list of the jumper settings depending on the card and firmware version.
Please mind that jumpers are populated or not populated based on the bus version of your card (Mega-ST or VME bus). Refer to the manual for the location of the jumpers.
Mk3 v1.0d - 1.1
Mega ST
CPLD Firmware V0
- A0/A1 - used for setting the IDE controller base address
- IDE - Closed: Enable IDE, Open: Disable IDE
CPLD Firmware V1
- A0/A1 - used for setting the VRAM base address.
Introduced with FPGA firmware V0205 which supports 4MB VRAM (24bit colour). - IDE - Closed: Enable IDE, Open: Disable IDE
TT / Mega-STe
CPLD Firmware V0
- A0/A1 - not used
- IDE - not used
- ADDR - Selects Atari Model. Closed: Mega-STE, Open: TT
CPLD Firmware V1
- A0/A1 - not used
- IDE - Closed: Enable IDE, Open: Disable IDE
Only works with HDDRIVER 12.6 or later. - ADDR - Selects Atari Model. Closed: Mega-STE, Open: TT
CPLD Firmware V2
- A0/A1 - used for setting the VRAM base address.
Introduced with FPGA firmware V0205 which supports 4MB VRAM (24bit colour). - IDE - Closed: Enable IDE, Open: Disable IDE
Only works with HDDRIVER 12.6 or later. - ADDR - Selects Atari Model. Closed: Mega-STE, Open: TT
For the Mega-STE you also need to set the A0/A1 for the VRAM base of 0xA00000!
Mk3 v1.1[a|b]
The version 1.1a was already shipped with the then latest CPLD and FPGA firmware. So the minimum firmware releases are covered here.
Mega ST
CPLD Firmware V1
- A0/A1 - used for setting the VRAM base address.
Introduced with FPGA firmware V0205 which supports 4MB VRAM (24bit colour). - IDE - Closed: Enable IDE, Open: Disable IDE
- ROM - Closed: Enable onboard TOS ROM, Open: Disable onboard TOS ROM
NB: The Mk3 1.1a card has a design mistake which requires a small soldering patch to make the ROM jumper work as expected. Additionally to pulling the jumper you need to connect the left pin to 5V, eg. available at the 3rd pin from right of TRAM socket “SLOT 2” using a jumper wire:
If you own the Mk3 1.1b, this is not necessary. Just pull the jumper.
CPLD Firmware V2
- A0/A1 - used for setting the VRAM base address.
Introduced with FPGA firmware V0205 which supports 4MB VRAM (24bit colour). - IDE - Closed: Enable IDE, Open: Disable IDE
Only works with HDDRIVER 12.6 or later. - ADDR - Selects Atari Model. Closed: Mega-STE, Open: TT
For the Mega-STE you also need to set the A0/A1 for the VRAM base of 0xA00000!
VRAM address setting
Here are two tables explaining the A0/A1 jumper settings depending on the bus version of the ATW800/2:
| A0 | A1 | Address | VRAM size | Remark |
|---|---|---|---|---|
| Open | Open | 0xC00000 | 2MB | Default setting |
| Open | Close | 0xA00000 | 2MB | Alternative range |
| Close | Open | n/a | n/a | NOT supported |
| Close | Close | 0xA00000 | 4MB | Needed for true-color |
| A0 | A1 | Address | VRAM size | Remark |
|---|---|---|---|---|
| Open | Open | 0x(FE)C00000 | 2MB | TT only Default setting |
| Open | Close | 0x(FE)A00000 | 2MB | Mega-STe or alternative f. TT |
| Close | Open | n/a | n/a | NOT supported |
| Close | Close | 0x(FE)A00000 | 4MB | TT only - Needed for true-color |