Looking to make an SA1 Dev board

Hey all, I'm looking to build a dev board for trying out various SA1 ROM hacks, and I was wondering if there were any boards that wouldn't work? I've looked at all of the different PCB types, and they all seem to have slightly different variations on each other. I just want to pick up the cheapest SA1 game to modify, but one that will be the most compatible. Also, my plan is to just install a socket in place of the old ROM chip, but just rewire the necessary pins, would that be the right method?

The only major differences between the different SA1 boards are the amount of RAM provided.

The PCB code tells you what any given board provides:
1L3B means
1 ROM
L SA-1
3 - battery-backed 8KiB SRAM (also seen: 0=none, 5=32KiB)
B - battery (also seen: N=no)
fifth digit: amount of not-battery-backed RAM
sixth digit: not-battery-backed RAM technology

Adding a socket is probably fine; the SA1 is fast compared to the rest of the SNES so avoid having a rat's nest of traces.

Awesome! I didn't know the PCB codes were identifiable in this way, this definitely helps thanks! And yeah, I agree a rat's nest of wires is undesirable, my plan is to only use wires for the few pins that need to be rerouted.

Really, what you'll ideally want is a 1L5B-xx where the "XX" is -11 or -12.... any number above -10. This is a 256k sram cart but can be easily expanded to 1mB sram.

Here is a dev. cart I made a while back. I upgraded the sram so it could test all games.
The rom, of course, is in a socket.

Oh, and I glued down the pcb so I wouldn't stress the adapter pins when changing roms out.

I may be being a complete idiot here, but may I ask why you'd want a revision above -10? I thought all the boards have the same kind of stuff on them with the same code, and so revision wouldn't matter?

~Molive

rev 02 only has enough lands for 32KB SRAM, while -10 and -11 have (resist-covered) lands supporting ... well, more SRAM. Could possibly be as much as would fit in a 32-pin package (=512KB)?

The different revisions are hardware changes. Some SA1 games, albeit only a handful, need sram larger than 256k (64k ~1L3B~ being the most common and 256k ~1L5B~ next common) so if you are going to make a development/tester board, one would assume that you'd want a pcb capable of utilizing the higher sram sizes. The 1LxB-10 and higher have sram footprints where you can swap the sram to a larger kilobit size, whereas, the lower revisions don't. There are enough connected address lines (on the -10 and higher pcbs) from the SA1 to mount a 2mbit sram but the largest sram ever used in a SA1 game was 1mbit (1L8B-xx). The 1L8B came in revisions below and above the "-10" and interestingly enough, a 1L8B could have a 512k or a 1mbit sram (the distinction being the "8" as the sram size indicator for both sram sizes) depending on the game.

Of course, just acquiring a game that already is a 1L8B would be the easiest solution to make a development cart.

Hey guys,
I've created a board which I can use for SA-1 dev. However, I've found that the Minipro programmer I'm using with an adapter is having trouble writing data to the 27c322 rom chips. Has anyone else had this problem before, or could anyone suggest why it's not working?
The chips read perfectly, but when trying to be written to there's an error on the first word and the program stops writing. I think it's that it thinks the data didn't save (it doesn't), but the error isn't described well in the message.

Thanks,
~Molive