Was going through my homebrew carts and I found this board inside
Star Versus:
Attachment:
batmap-000_board.jpg [ 191.84 KiB | Viewed 2218 times ]
Batsly posted about it
here, but didn't really explain the board other than it has 1MB PRG, and 32k CHR-RAM. Probably can't learn anything interesting from the photograph I took, more I'm just showing what the board looks like.
Anyhow, if anyone has any info on how to emulate this board, I'd love to know. I haven't figured out what the registers do yet. This hasn't by any chance already been emulated/documented somewhere?
As far as I know it's only been used in Star Versus. I think it was originally planned for
Super Russian Roulette but he decided to make some new ultra hyper mega mapper for that instead.
A first step is to see what connects to what pins. If you can't see any connection to, say, CPU A4, then you know anything the software does with A4 is irrelevant.
What model of Xilinx CPLD is on there? The etching is harder to read than the silkscreening on the flash.
Judging from the footprint and voltage regulator I'd say a XC9536XL or XC9572XL.
Ah, sorry about the poor picture quality. I didn't expect anyone would want to trace the lines or anything. I'll try to take some better images, though the black finish is making it difficult.
CPLD: XC9572XL
RAM: IS62C256AL
ROM: 29F200CBMI-70G
The black resist isn't actually that much of a problem, but with the hidden traces under all the SMT parts I don't think I'd get very far. It's just that my first intuition when it comes to reverse engineering things is figuring out the size of box that the device has to fit into; i.e. in this case, what signals are available for the CPLD to work with.
Stopping before I get too involved, I'm going to stop with observing that CPLD pin 1 is CIRAM A10.
Well, if they're interesting to anyone, here's some pictures with better detail, with some alternate angles trying to show everything that can be seen through the lighting.
Ah, maaaaan, if you're going to just dangle that in front of me...
Definitely an MMC3 variant of some flavor. /IRQ; capacitor on PPU A12; mirroring control; 1 KiB granularity on CHR RAM. PRG A12, A11, and A9 definitely connect to the card edge. A14, A13, A0 are available to the CPLD. CPLD controls some kind of write protect for the flash (i.e. R/W connects to flash /WR, but flash /OE and /CE connect to CPLD).
There's an extra three traces on the underside from the flash to the CPLD beyond what "should" be necessary; no idea what they could be for.
CPLD mostly laid out as 1-11=bottom: inputs from CPU/PPU; 12-22=right: cpu data bus; 23-33=top: prg banking; 34-44=left: chr banking.
rainwarrior wrote:
As far as I know it's only been used in Star Versus.
It was also used in the Anamanaguchi kickstarter cart. I don't have one myself to check for sure, but in this photo you can see a section of the PCB through the transparent window in the cart shell.
It's possible that it's also in the Anamanaguchi Power Supply 10th anniversary cart as well - I do own one of those, so I can check and provide photos if anyone's interested.