Create and burn eproms for standard Jaguar 2 chip cartridges

[Gedalya]

7 hours ago, Gedalya said:

@Dragonstomper, this is a wonderful guide and very helpful for someone like myself. I do have a recommendation; quoting from the guide:

 

I believe the last reference should read "DIP IC" and not "DIC IP"; also I think the same line should be edited to include the information "2.54 pitch" to delineate the 42 pin DIP IC socket as there are two, a 2.54 pitch and a 1.78 pitch, the 1.78 being smaller.

 

Lastly, there is a sentence that reads "don’t through the eprom away.", I believe that should read "don’t throw the eprom away.".

Again, this is a wonderful guide, thank you very much for sharing as it has been a major boon as I try and navigate this subject.

Oops, ment to tag @rayik on this and not @Dragonstomper.

[rayik]

@Gedalya

 

Corrected the typo and added the pitch.  Thank you.

 

Glad you found the guide useful!  I have to thank the BSG authors for the inspiration to create the guide.  Skunkboard would not run this game.  While it probably cost as much or more for everything used in the guide I rather spend the money figuring out how to roll my own rather just than pay the ebay rate.  Game Drive now runs just about everything.

[Gedalya]

Can the knowledge in this thread be used to make the equivalent of an Atari Jaguar CD Memory Track? I presume no but I am curious as I could use one at this time and it seems more interesting to make than buy off eBay. 

[Zerosquare]

No, the Memory Track PCB is different from the standard cartridge one. It would be possible to recreate it, but I've never heard of anybody doing so. That being said, I don't know if there's a real demand for it, now that there other ways to play most of the JagCD's library.

[Gedalya]

44 minutes ago, Zerosquare said:

No, the Memory Track PCB is different from the standard cartridge one. It would be possible to recreate it, but I've never heard of anybody doing so. That being said, I don't know if there's a real demand for it, now that there other ways to play most of the JagCD's library.

Thanks. Does anyone have any technical information on the Memory Track? Perhaps a photo of the internals?

[Zerosquare]

http://www.mdgames.de/jag_mem.htm

Edited March 9, 2022 by Zerosquare

[+cubanismo]

FWIW, I've been looking at these lately for reasons. The BIOS code appears to support either an atmel or AMD chip, detected at runtime. It uses a clever trick to access the 8-bit flash chip while the memory controller is in the 32-bit ROM mode the JagCD uses in it's primary operation mode: The Jag address lines are wired to the flash chip offset by two, so jag a2-> flash a0 so and so on, then ROM2 is wired to the flash CE. The 8-bit word then ends up in bits 16-23 of a long word at address (flashAddr * 4) for both reads and writes.

 

The BIOS isn't accessed after boot. It just copies itself to RAM at magic offset $2400 then retuns to the JagCD BIOS if you don't invoke the manager UI.

 

The EPROM holding the BIOS appears to be the same model used for the Jag BIOS. Can anyone confirm?

 

If you wanted to change flash chips, the BIOS source code is available and mostly builds. It's pretty easy to swap in different flash commands.