@nprofile1q... @nprofile1q... the most complex part so far has been bus and clock timing for SDRAM. But the second most complex part was speccing an entirely custom video processor for this machine because none existed that met my requirements.
I actually had the AI scrape up all information it could find on the Sega Genesis video chip (Yamaha YM7101) and then write comprehensive specifications for that. Then I incrementally added new features to the specification for enhancements. Then I had it write a clean room implementation of the specification. and it fucking works.