Likewise the Sega Master System used a Z80 as its CPU; later, Sega used it for the Genesis / Mega Drive's sound management processor (plus a Yamaha synthesizer)

Likewise the Sega Master System used a Z80 as its CPU; later, Sega used it for the Genesis / Mega Drive's sound management processor (plus a Yamaha synthesizer). If you plugged in the Power Base Converter, the Z80 would become the CPU and let you play Master System games.