I guess it had to happen sometime — and close to fifty years is one hell of a good run for an 8-bit microprocessor from 1975. This week, Zilog announced that it would be moving the storied Z80 microprocessor family to EOL status, and called for last-time-buy orders through June 24.
I took the opportunity to place a small symbolic order for a single chip for the Mini Museum — a processor that 1975 would have drooled over. The Z84C0020PEG is a power-efficient, DC-clockable, 20MHz CMOS version of the venerable Z80 microprocessor. In car terms, it’s a Z80 with a quad barrel carb, dual chrome exhaust, and a sweet paint job.
Even this one is five years old, bought “new” from Mouser this month.
The Z80, itself a software-compatible improvement on Intel’s popular 8080 microprocessor, is probably in several billion devices, at this point. It has been used to control everything from robots to the Nintendo Game Boy to microwave ovens, as well as its usual use in 8-bit computers, typically running the CP/M operating system. It anticipated the past few decades of PC upgradability by providing a faster, more capable version of the 8080 that could run on the same software as the 8080, if needed, just like later generations of PCs can (usually) run software from at least the previous generation or two.
While the eZ80 will continue to be produced for the foreseeable future, it’s not quite the same for hobbyists and educators like me who grew up with the Z80 (it powered the Timex-Sinclair 1000, which was my first computer). I understand the business case for the decision, though — we’ve long since switched to 32-bit processors even for our Microcontrollers class, and last year, we replaced the Z80 Microprocessors course content with a Verilog-based approach, where students design their own processors. (I do still use the Z80 for opcode examples.)
Although I wouldn’t use a Z80 in a new design, it’s still bittersweet to see it replaced by more modern tech. But I guess for nostalgia, we’ll always have the good old 16F84A. (That’s so deeply entrenched in engineering curricula that Microchip will be stuck making it until the heat death of the Universe!)
