Four Chip Game PCBs

[Tenorman]

Hello All,

 

Has anyone here successfully burned a 4 MB ROM to 4 x 1MB 8-bit EPROMs and got it working with one of the four chip PCBs?

 

I am trying to make extra copies of a couple games to use with Jaglink (Gamedrive and Jaglink are not compatible).  I got the 4 x 8-bit boards mainly because I can write the EPROMs without adapters or doing anything special with the programmer that I have.

I have not had any problems with 4 x 512KB EPROMs and 2 MB games.

 

Things I have tried:

-AT 27C080 EPROMs

-ST 27C801 EPROMs

-Both re-writing the header using Tursi's makefastboot and not doing this.  Looking at the ROM with a hexeditor I don't think I should have to.

-Split the ROM into U1-U4 using romsplit and write it out.

 

I have found conflicting information.  A couple posts indicate that you can use 1 MB EPROMs to make a 4 MB game, others indicate these PCBs are only compatible with 512K EPROMs to create 2 MB games.

Are these compatible or not?  Do I have to do anything special to get the 4 MB ROMs working on this board?

 

Thanks.

 

[Zerosquare]

Where did you get the PCB from? What do they look like?

[Tenorman]

It is this one:

https://www.ebay.com/itm/130888371100?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=OCU7iSyvSpa&sssrc=2047675&ssuid=ILtXf2HqQEi&widget_ver=artemis&media=COPY

 

This is the board that Atari's romsplit.exe targets when you use the -b option.

 

[Zerosquare]

This PCB is indeed designed for 2 MB, split into four 512 kB memory chips:

http://mdgames.de/jaggc4ic.htm

 

To use 27C080 chips instead, you'd need to disconnect pin #1 of the memory chips (if it's connected to +5V), and connect it to pin 5B of the cartridge slot.

 

Edited December 19, 2023 by Zerosquare

[Tenorman]

Thank you, I was having trouble finding a definitive answer on this.