The Z80 microprocessor was designed in 1974 and was intended to be a binary-compatible, improved version of the Intel 8080 with a higher clock speed, a built-in DRAM refresh controller, and an extended instruction set.
It was used extensively in desktop computers of the late 1970s and early 1980s, arcade video game machines, and embedded systems, and it became a cornerstone of several gaming consoles, like the Sega Master System.
During the mid-late 1970s, the Z80 became a popular CPU for S-100 bus machines, which were early personal computers with a 100-pin modular bus system that allowed swapping cards to build systems based on parts from various manufacturers.
Digital Research targeted the Z80 as a key platform for its CP/M operating system, and the association between Z80 and CP/M stuck, powering dozens of small business computers until the mid-1980s, when IBM PC clones running Microsoft’s MS-DOS became the new industry standard.
Interestingly, Microsoft’s first hardware product, the Z80 SoftCard for the Apple II in 1980, added the famous Zilog CPU to the classic personal computer and allowed users to run CP/M on that machine. In 1982, Bill Gates claimed that SoftCard installations represented the largest single user base of CP/M machines.
Zilog is notably discontinuing several Z84C00 chips that are still available in classic 40-pin DIP packages resembling the classic Z80 CPU chips of the 1970s. (These standalone chips include a CPU and nothing else, unlike a microcontroller, which can include RAM and other accessory devices.)
The DIP design features two rows of 20 pins with a plastic package in between that contains the actual embedded silicon chip, resembling the classic Z80 CPU chips of the 1970s.
