Question about DIY GB flashcarts, LSDj and SRAM (Page 1) - Nintendo Handhelds - Forums

1 Jul 3, 2014 7:12 am

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Hello,

I'm looking into making my own GB(C) flashcart, using the trick that consists in replacing the game ROM with a flash chip on a suitable commercial cartridge.

While starting to gather the different parts needed for the project, I suddenly realise that I am unlikely to find commercial carts with 128K SRAM, which I believe is needed for LSDj to deal with more than one song at a time.

So, my question is: are there drop-in replacements for the SRAM chip to extend the cart to 128K?

Thanks!

PS: Please do not suggest a commercial flashcart as a workaround, I am interested in doing the mod to learn a bit more about the GB(C) cart hardware

2 Jul 3, 2014 10:37 am

12ianma

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I believe some games may have had that much. I can't remember exactly, I'm sure someone will.

3 Jul 3, 2014 6:40 pm

ultrageranium

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12ianma wrote:

I believe some games may have had that much. I can't remember exactly, I'm sure someone will.

Unfortunately there were very very very few, and not the easiest ones to find or that you would cannibalise I imagine.

GAMEJACKV2,32,128,ROM+MBC1+RAM+Battery,JPN,Challenger GB BIOS [C][!].gb.gz
SUPER GALS,4096,128,ROM+MBC5+RAM+Battery,JPN,Chou Gals! Kotobuki Ran (J) [C][!].gbc.gz
EMSMENU,32,128,ROM+MBC1+RAM+Battery,JPN,EMS Multi-ROM Menu V1.0 (PD) [C][h1] (Set Colors).gbc.gz
EMSMENU,32,128,ROM+MBC1+RAM+Battery,JPN,EMS Multi-ROM Menu V1.1 (PD) [C][h1] (Set Colors).gbc.gz
EMSMENU,32,128,ROM+MBC1+RAM+Battery,JPN,EMS Multi-ROM Menu V1.2 (PD) [C][h1] (Set Colors).gbc.gz
EMSMENU,32,128,ROM+MBC1+RAM+Battery,JPN,EMS Multi-ROM Menu V1.3 (PD) [C].gbc.gz
GAMEBOYCAMERA ,1024,128,Nintendo Pocket Camera,INT,Gameboy Camera Gold - Zelda Edition (U) [S].sgb.gz
GAMEBOYCAMERA,1024,128,Nintendo Pocket Camera,INT,Gameboy Camera (UE) [S][b1].sgb.gz
GAMEBOYCAMERA,1024,128,Nintendo Pocket Camera,INT,Gameboy Camera (UE) [S][!].sgb.gz
GB WARS3,1024,128,ROM+MBC5+RAM+Battery,JPN,Gameboy Wars 3 (J) [C][!].gbc.gz
TEST,2048,128,ROM+MBC5+RAM+Battery,JPN,GB Gamejack 16M Test (Unl).gb.gz
MOBILEGOLF,4096,128,ROM+MBC5+RAM+Battery,JPN,Mobile Golf (J) [C][!].gbc.gz
OBGBTC,32,128,ROM+MBC5+RAM+Battery,JPN,OBGBTC (Tile Creator) (PD) [C].gbc.gz
POCKETCAMERA,1024,128,Nintendo Pocket Camera,JPN,Pocket Camera (J) (V1.1) [S].sgb.gz

So the question remains ... Is it possible to take a cart with 32K SRAM and upgrade it to 128K?

4 Jul 3, 2014 7:56 pm

nitro2k01

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Sweeeeeeden

It should be possible. You could use an existing cartridge, but apart from GB Camera, the games listed above are super rare.
for inspiration on how to convert a game cartridge to a flash cartridge, see:
http://www.reinerziegler.de/readplus.htm
For their suggested methods, you would take a PLCC package flash chip and place at an angle. There might be flash chips for sale that are plane drop-in replacements, though.

As for SRAM, you need to find a suitable SRAM chip that is still for sale. It needs to be a 5V, low power, 128k x8 SRAM chip. Here's a random one I found and it seems to be for sale, still:
http://www.tme.eu/en/Document/add608bde … C1008L.PDF
If you get the right package, you should be able to solder it onto the footprint of the GM76C256CLL chip used on MBC5 cartridges, and get it working with just a couple of mod wires.

But you do need to make sure that the donor cart is an MBC5 game, or you won't be able to do the RAM expansion. (MBC5 is the memory controller chip in the cartridge.) That is, cartridge type ROM+MBC5+RAM+Battery.