I am receiving a Leaper 3D as a belated xmas present (come tax return time), so I will be able to further develop on this project, it will just be some time.
In the meantime, I have been trying to get some 2x010's I have lying around to work in place of a 2x32. I've tied the VCC to the VPP, and both to the pin that should be the VPP, but this does not seem to be enough.
I mirrored the data so that it would take up the whole 131,072 byte space of the chip, and since a Game Genie has a 2432 for PRG ROM instead of a mask ROM, then a 27,28, or 29 or equal or larger size should work in it's place.
Any suggestions:?
I'd say hook the extra address lines up to VCC also, instead of mirroring. The possibility of random bankswitching doesn't sound good.
When I find the digital camera, webcam, eyetoy, scanner, etc. I'll post pictures, but I seem to be having trouble getting this chip off the ground. Instead of a generic 2732, I am using a 120ns 29C010 from Atmel. (AT29C010A).
No matter how well I conncect it, It just won't run any code (It currently has a mirrored copy of the PRG code from an actual Game Genie).
The Copy is correct, I did check that, but the NES just won't accept my EEPROM.
Would CMOS actually cause trouble with these circuits, or should I consider another chip.
BTW: Haven't tied all spare address lines high, but I am going to do that real soon, just to be sure.
Hmm, I re-read your old post and you said GG uses a 2432. What exactly is that? I looked in Jameco's catalogue, they have a 24C32, but that's a 4k*8 serial eeprom.
Is it a custom chip, perhaps? There were enough GG's made where it would seem possible maybe.
But I would definitely try hooking the unused address lines up to something first. Having the upper address lines randomly change in the middle of reads, etc. couldn't be good at all. Even if the ROM is mirrored internally.
I made a mistake in that old post. It is indeed a 2732 that they use (I says that underneath the PROM when you remove it). I have tied all the aditional lines high, and still no luck. What is really ticking me off with this board is that all the lines are correct, yet I cannot get any of my 29010's that I have to work with this board. Any aditional suggestions? BTW: I have the pictures, but I have not u/l'ed them yet
Nuts. Well, I can take random guesses, heh. Works sometimes.
Are there at least 2 capacitors on the board (one electrolytic and one ceramic '104')?
Is the original 2732 marked with a part #? Are the pins still intact enough to where you can try dumping it? I guess that wouldn't help much though, if you've already verified the pins from the cart edge.
If you're using a front-loader, is the lockout chip pacified? Everything connected ok?
I finally got pictures uploaded:
Game Genie PROM in all it's glory:
The Small Sized chips board:
And The multi-sized chips (up to 32 pins) board:
I also forgot to mention that although the EEPROMs do not work in the slots, I can still use the 2732 in the sockets