Atari ST micro ATX

This page contains the work I have done for resolving things and developments for the great micro ATX Atari ST board designed by Angel_X on the Polish forum.

The Micro ATX Atari ST is a board designed to fit inside a standard micro ATX PC case.  Here are the features added to the board:

  • ISA slot for ET4000 1mb VGA video cards
  • 40 pin IDE interface
  • VGA header for standard VGA video output to monitors that work with 15khz
  • Dual TOS 2.06/1.04 switchable by 2 sets of jumpers
  • Standard 20 pin ATX power connector (required for ISA video cards)
  • PS2 mouse and keyboard ports using Eiffel technology
  • 4mb RAM memory on plugin card with jumper to set as 1mb or 4mb

 

Links to Angel_X project site:

http://ataripcb.pl/atari_st_atx_v1.1.html
http://ataripcb.pl/atari_st_atx_ram_board_1.html

Issues found:

  • Parallel 26 pin header pin-out does not match standard IDC parallel adapters used with PCs.
  • Serial 26 pin header pin-out does not match standard IDC serial adapters used with PCs.
  • ACSI 20 pin header pin-out does not match one used by UltraSatan and SatanDisk
  • MIDI in does not currently work
  • Availability of IDC 16 pin to VGA adapters is low to buy

 

26 pin Serial and Parallel header

The parallel and serial 26 pin headers on the board are not correctly pinned, the pins alternate between top and bottom.  This adapter PCB provides a header that has the pins 1-13 in one row with 14-26 in the second row and matches standard parallel IDC to DB25 adapters that are available.  The PCB has a female header on the bottom that plugs into the ATX board and male header pins on top for connecting to.

Parallel position

Serial Position

Download Gerber

ACSI 20 pin header

The 20 pin ACSI header on the board is again pinned with alternating pins on top and bottom. This adapter PCB provides a header that is pinned 1-10 in one row and 11-20 in the second row and matches the standard UltraSatan IDC ribbon cables available. The PCB has a female header on the bottom that plugs into the ATX board and male header pins on top for connecting to.

Download Gerber

VGA to IDC 16 pin header

This adapter PCB allows for the VGA header to be used to provide a standard VGA connection via a 16 pin IDC ribbon cable.

Download Gerber

MIDI-In Fix Adapter

This adapter swaps pins 4 and 5 on the 4N33 OKI chip as they are connected the wrong way round on the mATX board.

Gerber will be made available after testing is completed

ISA Cartridge Adapter Board

This adapter board fits into the micro ATX ST ISA slot to provide additional functionality.  Initially designed to provide a standard Atari ST cartridge port.  The Adapter requires ROM3 and ROM4 from the GLUE chip, so wires are required to be soldered to the bottom of the micro ATX board to be used on 2 pins on the ISA card.

Version 1.0 – Initial test version with cartridge connector flush with ATX casing (tested and works)

Download Gerber

Version 1.1 – moved cartridge connector outside the ATX casing to allow cartridges in cases to be used (tested and works)

Download Gerber

Version 1.2 – added Forget-Me-Clock II component option and internal 40 pin IDC header

(tested and works)

Added an internal header which can be used for connecting an EtherNEC adapter.

Testing has confirmed that this version works.  FMC-II RTC clock and cartridge both work fine.  However testing of this version identified that GND was routed through the ISA slot to the Dallas chip so I moved to version 1.3 below with this fixed so that when you remove the ISA Cartridge Adapter card from the ISA socket that the clock keeps going.  Also, testing showed that you need a voltage on the mATX board greater that 4.8v for the cartridge socket ROM3 pin to work correctly through the RTC pins CEI/CEO.  If you have this version of the board, I recommend adding a bodge wire between the battery GND pin and pin 8 on the RTC Dallas socket/chip.

Download Gerber

Version 1.3 – added Forget-Me-Clock II component option and internal 40 pin IDC header(currently not tested yet)

The following have been changed on this board version:

  • Fixed GND battery connection to FMC-II Dallas chip pin 8.
  • Changed Battery holder for SMT version as these are easier to get hold of.

 

Internal header can be used for connecting an EtherNEC adapter.

Download Gerber

EtherNEC ISA Network adapter (Tested and works)

I have re-made the old EtherNEC adapter to test with the internal 40 pin IDC header on the ISA Cartridge Adapter Board.  It connects using a standard IDC 40 pin ribbon cable.

Download Gerber

This page contains the work I have done for resolving things and developments for the great micro ATX Atari ST board designed by Angel_X on the Polish forum.