Zilog Z80

Federico Faggin had led the work on both the 4004 and the 8080 at Intel before founding Zilog in 1974. The Z80 ran 8080 machine code unchanged but added a set of shadow registers, the IX and IY index registers, block and bit instructions, a single supply voltage instead of three, and built-in refresh for dynamic memory. For a designer that meant fewer chips on the board at the same price.

It duly became the standard processor for CP/M machines and for home computers such as the ZX Spectrum, TRS-80 and MSX, and a modified variant sits inside Nintendo's Game Boy. In 2024 Zilog announced the end of production for the classic Z80 parts, after almost half a century.