It was 52 years ago today, on October 31, 1974, that Federico Faggin (pronounced FAHH-jeen), the mastermind behind the early Intel CPUs, left Intel to try something else. His next big thing was the legendary Zilog Z-80 CPU.
Yet another Fairchild alumnus
Faggin, like the founders of Intel, previously worked at Fairchild. Faggin left Fairchild after Gordon Moore, Robert Noyce, and Andy Grove, coming to Intel in 1970. At Fairchild, he had been designing chips that used Silicon Gate Technology, and Fairchild wasn’t taking full advantage of the technology. He wanted to use SGT to design advanced new computer chips.
Why Federico Faggin left Intel
Faggin famously was involved in all of Intel’s early CPUs: the 4-bit 4004 and 4040 CPUs, and the 8-bit 8008 and 8080 CPUs. The 8080 CPU saw widespread use in early kit and homebrew computers. The first ever Microsoft product ran on the 8080 CPU. So did the famous CP/M operating system.
But Intel wasn’t yet sure of the market for CPUs. So they developed a habit of delaying his CPU projects and putting him on less-interesting work. Like vending machine parts. Yes, vending machine parts. The final straw for him was when he was reprimanded for starting his workday later than 8am. He often worked well into the night and thought his work after 5pm should count.
So once he lined up the funding to start a new company, he quit his job at Intel to start something new. And then he didn’t have to worry about answering for what time he started his day, or getting reassigned randomly.
Federico Faggin and the Zilog Z-80
Faggin’s next company, Zilog, was the first company to specialize in microprocessors. Its first product was the very famous Z-80 CPU, which took the 8080 in a somewhat different direction than Intel did with its followon 8085 CPU. The Z-80 was completely compatible with the 8080, but included numerous enhancements that made it especially well suited to creating home computers and game consoles with it.
It wasn’t long before the Z-80 became the preferred CPU for running CP/M, but it ended up in numerous other platforms as well. The “80” in Radio Shack’s TRS-80 came from the Z-80 inside it. Sinclair used the Z-80 in its inexpensive home computers, as did Amstrad. This makes the Z-80 particularly beloved in the UK, since so many people grew up using Z-80-based microcomputers there. The MSX architecture for home computers also used a Z-80 CPU. The Coleco Vision and Sega Master System game consoles also used it, and the Sega Genesis even utilized a Z-80 as a secondary coprocessor. A Z-80 add-in card was a popular Apple II accessory with an unexpected history, and Commodore sold a short-lived Z-80 add-in for the Commodore 64.
And here’s a fun one. Datapoint, the company that commissioned the original Intel 8008 CPU, didn’t end up using it. A few years later they used a microprocessor in a product for the first time, but it wasn’t an Intel chip. The first microprocessor they used in a product was a Zilog Z-80.
The popularity of 16- and 32-bit computers caused the Z-80 to wane in the mid to late 1980s, but it remained a very useful and popular niche CPU, not just for years, but for decades. The Z-80 was not discontinued until June 14, 2024. That’s a tremendous legacy.
David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.