I finished up the FPGA Videobrain now. Most of the work was reverse engineering the original system, which took forever. I have completed that work and the document I wrote, “Videobrain Unwrapped” is available here:
Not much more to say about it, other than I verilogged (is that a word?) the Videobrain and stuffed it into an FPGA. Everything seems to work fine including joystick reading, which I have made work with a D-pad. This is not 100% optimal since most games actually DO use the analog nature of the stick, but it gets it working for now. Dropping in “analog” values in the future will require no more than 5 minutes, because I am properly emulating the joysticks.
Here’s a youtube video of it in action, playing a few games:
Next up: FPGA Arcadia 2001!