> The other surprising thing is that you could actually run the Z80 in parallel with your 68000 when running a Genesis game. We used the Z80 as a sound co-proce

> The other surprising thing is that you could actually run the Z80 in parallel with your 68000 when running a Genesis game. We used the Z80 as a sound co-processor running MIDI and playing sampled drums without bothering the 68000. I always thought that was a key reason to include a Z80. A dedicated sound processor (often Z80) was a mainstay of arcade games from the mid-80s and onward and SEGA's engineers would surely have been familiar with such a design. It might even have helped when porting arcade games.