This is a twist on classic DFO from Micro where I put a PIC16F630 and the back for the switchless mod. You need D4S code.
https://nfggames.com/forum2/index.php?topic=5744.0 https://oshpark.com/profiles/micro
https://circuit-board.de/forum/index.php/Thread/7810-Sega-32X-Switchless-Mod-f%C3%BCr-Mega-Drive-1-und-auch-2/?s=005d89b5fd35d5ff06d198493b633b89d1ca043f