Any info on: Nintendo Gameboy メモリ カートリッジ (memory cartridge)?

[grahf!]

Hey guys. Long time reader, but haven't posted here until today. Anyhow, I recently moved to Japan. I've picked up a few of the official Nintendo flash cartridges, including a Gameboy one. For anyone not familiar, these could be re-programmed in convenience stores.

My question is this: is there any information out there about reprogramming these? I know the official dev-carts could be programmed with homebrew hardware, but I can't find any information about these ones. The "mystery" chip inside is a Megachips mx15002UCA. I wonder if anyone knows where to find a PDF for this? It says MMC1 on the board next to it, but its obviously more than that.

[c0ldb33r]

Wow, I never knew these existed.

It must accept Gameboy roms and also Gameboy Color roms right? The copyright notice is 1999 and the Gameboy Color lauched in Japan in 1998.

[grahf!]

Yeah, works with both. There isn't really much difference between a classic and color cartridge, its all in the rom. A local game shop has another one of these carts for sale that contains Super Mario Brothers DX. Unfortunately mine only has two B&W games: Kirbys Dream Land and Medarot.

[jb143]

MegaChips Corporation is a Japanese company that makes specialty chips for the game industry...so getting a datasheet probally isn't going to be easy. I'd image that they're not allowed to give them out but your best bet would be to contact them and ask. The chip does seem to be availabe through several destributors specializing in obsolete chips though so you never know.

Here's their website and email if you want to try...
http://www.megachips.co.jp/english/top.html
info@megachips.co.jp

My best guess is that it's a special Memory Bank controller specially designed to work with a menu system or something similar. Or it could be allowing to it opperate as any MBC chips so any game can run(Though I think a normal GBC chip will do that anyways). Worst case is that it could also have special hardware in it so it will only let you program it from the right programmer. The flash chip is probally standard though so you CAN program it. It's just a matter of connecting to it.

[grahf!]

Thanks for the info JB. I was already thinking that it was proprietary.. Another thing of note is that this cart has a massive 1megabit SRAM, and a double sized battery to match it. The biggest i've seen in normal carts is 256kb, so I assume that this MMC keeps things seperated by game.

Yes it is a normal flash rom, and i'll probably start figuring out the pinout for this cart soon. I just wanted to know if soneone had already dont it before I delve into it.