First out the gate is the ROM board...
Which currently supports Joust, Stargate, Robotron, Bubbles,
Splat ( yes with the SC2's ), Stargate and Sinistar with extra 4k of RAM.
There's a socket for extra SRAM hiding under the NVRAM.
Defender will work but requires a ROM patch, which Sean Riddle already
went to the trouble of documenting Sean
Riddle's Home Page
The Complex Programmable Logic Device ( CPLD ) integrates all the
TTL logic from the original board along with the 6821 PIA and the two Special Chips. Plus with Sinistar the Special Chip 'window' feature.
For this design the CPLD is a Xilinx XC95288XL, which ends up at almost
90% utilized because of the requirement to support the special chips. The
design for the Special chips came from a SC1 prototype I did a couple of
years ago as a proof of concept...
picture of a scarily wired proto board.
TQFP parts are really quite challenging to solder although the board
etching with 10 mil features came out really well.
The NVRAM from the CPU board is replaced with an FRAM non-volatile
memory placed on the ROM board, so no more batteries EVER ! It has also proved to
be pretty hard to accidentally erase. Finally it uses a full 8 bits of memory for