M68k and Z80-based

The Zilog Z80 8-bit processor is an Intel 8080-compatible processor, which competed with other microprocessors during the 1980s, powering home computers and gaming systems including the Nintendo Game Boy, Sega Master System, Sinclair ZX80/ZX81/Spectrum, MSX, and Tandy TRS-80.

Zilog introduced an MCU (Z380) based around the Z80 microprocessor in 1994, with various updates over the years, including the Z8, eZ80, and others. Z80 clones are also quite common.

Another popular 1980s era microprocessor is the Motorola 68k (or 68000). It's 16-bit for its ALU and external data bus, but with 32-bit registers and 32-bit internal data bus. After its introduction in 1979, its architecture is still in use today, with Freescale Semiconductor (now NXP) producing a number of 68k microprocessors.

Motorola introduced numerous MCUs based around the 68k architecture, including the MC68320 communications controller in 1989. Current 68k-based MCU designs include the ColdFire, which is a fully 32-bit design.