Genesis EEPROM Dumping Guide

[Rixel]

I had been looking around for this and hadn’t found something comprehensive. I somewhat recently acquired two prototypes on EEPROMs. One is mounted to a test board but doesn’t run anymore (board rot potentially) the other is 4 loose chips that I was able to dump but they don’t checksum and I haven’t been able to get them to merge together.

I’d love to find, or create, a guide to doing this. One of the protos I can share if I can get it working. The other is something I’m working for a friend. If anyone has something written or knows of something let me know.

Thanks!

 

[Bad_Ad84]

What chips are they on? Sega games use 16 bit wide bus, so if the chips are 8 bit, you need to interleave them. Need some more info to help

 

[Nemesis]

Most people dump Mega Drive games through the cartridge port, either with a standalone device or through the system itself (IE, this method developed by Mask of Destiny). That said, if you've got bare or removable EPROMs, and you're comfortable dumping EPROMs with a separate reader, that's certainly an easy method. As Bad_Ad84 mentioned there's a 16-bit bus on the Mega Drive and your EPROMs are almost certainly 8-bit, so you'll need to identify which ones are odd and which are even and interlace them appropriately. Mega Drive games should all have an easily identifiable ROM header with plain text strings that generally make this process straightforward.

 

[ERROR]

There is a program called interleaver that works. I’ll find a link or upload it.

There isn’t much info out there on how to do this. WinHex has a combine option that can interleave them.

 

[ERROR]

Here’s an example of 2 8 bit eprom headers that need to be interleaved.

It is odd and even bytes.

 

[Ice Man]

Mega Drive/Genesis uses 16-bit EPROMs such as 27C400/800/160/322.
Any compatible universal programmer with adapter should be able to read them e.g. TL866 + customer adapter or TOP3000/TOP3100 as well GQ-4X4 + adapter.

More information on your EEPROMS would be appreciated.

 

[Druid II]

If you are unfamiliar with interleaving/byte swapping, then just upload the raw rom dumps and someone more knowledgeable will fix it up for you.