There's a PR open with some CD dumps:
https://github.com/mamedev/mame/pull/3189 , but without a driver it doesn't make much sense to merge it.
Here's a PCB pic (credit: incog):
https://imgur.com/a/1LO1QKoAccording to Robbbert there are at least 2 chips with internal ROM:
uPD78214GC = CPU with 16K of ROM and 512 bytes of RAM, various i/o, uart, timers, etc
TMP87C800F = CPU with 8k ROM and 256 bytes of RAM, various i/o, timers, etc