Z80—The 1970s Microprocessor Still Alive

Reports on the history, development, and applications supported by Zilog Z80 microprocessor. The history of Zilog Z80 is fascinating. According to reliable sources,1 in late 1974, Federico Faggin, who was then best known as the designer of the first commercial microprocessor Intel 4004, and Ralph Ungermann, from the Intel 8080 team, left Intel to form their own company. Then, Masatoshi Shima, who was the transistor-level designer of Intel 8080, left Intel in April 1975 to join Faggin and Ungermann. At the beginning, Faggin intended to develop a single-chip computer (microcontroller), but soon realized that it is difficult to compete in the microcontroller market with a company who has its own semiconductor fabrication facility. In December 1975, Faggin came up with an idea of developing a 5-V microprocessor, which was machine core compatible with then popular Intel 8080, and adding most of the functionalities available in Motorola 6800, so that they could pinch both markets. Faggin, Ungermann, and Shima managed to find a venture capital from Exxon Enterprises for the development of a new microprocessor Z80 and formed their own company Zilog.