The Mega Drive 1 and 2 used a Z80 to retain backwards compatibility with the Mark III (Master System). Sega manufactured and sold a device called the Power Base Converter to retain compatibility. The Mega Drive 3 as well as other systems (Nomad, CDX) released at the end of the system's life did not have the Z80.
Actually, the Z80 in the Sega Mega Drive was used as the sound processor, the program for which was provided alongside the 68xxx code in the cartridge - a Mega Drive without a Z80 would have been unable to run games, as many games expected to be able to communicate (sending commands and receiving responses) with the Z80.
Since the Z80 had it's code provided by the cartridge however, I assume it could also have been used for the Master System compatibility. Apparently the Power Base Converter works on all Mega Drives, the only issue is the plastic shell it's in might not fit the specific model of Mega Drive, requiring it to be taken apart.
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The Mega Drive 1 and 2 used a Z80 to retain backwards compatibility with the Mark III (Master System). Sega manufactured and sold a device called the Power Base Converter to retain compatibility. The Mega Drive 3 as well as other systems (Nomad, CDX) released at the end of the system's life did not have the Z80.
Actually, the Z80 in the Sega Mega Drive was used as the sound processor, the program for which was provided alongside the 68xxx code in the cartridge - a Mega Drive without a Z80 would have been unable to run games, as many games expected to be able to communicate (sending commands and receiving responses) with the Z80.
Since the Z80 had it's code provided by the cartridge however, I assume it could also have been used for the Master System compatibility. Apparently the Power Base Converter works on all Mega Drives, the only issue is the plastic shell it's in might not fit the specific model of Mega Drive, requiring it to be taken apart.