The Z80 is an eight-bit microprocessor introduced in 1976 by Zilog, Inc. Since its release, it has been used in many desktop, embedded, and military computer systems. The first Z80 chips ran at 2.5 MHz, gradually increasing in speed up to 20 MHz. One of the most successful CPU ever produced, the Z80s design was eventually licensed to other companies for production, including Toshiba.
Advantages over Intel's 8080 processor
- An enhanced instruction set that allowed bit manipulation, block move, block I/O, and byte search instructions.
- New index registers with instructions for direct base+offset addressing.
- An improved interrupt system.
- Simpler hardware requirements for supplying power to the chip, generating clock cycles, and interfacing with memory and I/O devices.
- The ability to reset only the program counter without resetting all data in the chip allows its use in development systems such as circuit emulators.