Zilog Z280

The Z280 in a PLCC package

The Zilog Z280 was an enhancement of the Zilog Z80 architecture introduced in July 1987, basically a slightly improved CMOS version of the earlier NMOS Zilog Z800, both versions were commercial failures. They added a memory management unit (MMU) to expand the addressing range to 16 MB, features for multitasking and multiprocessor and coprocessor configurations, a 256 byte cache, and a huge number of new instructions and addressing modes (giving a total of over 2000 combinations). Its internal clock signal ran at 2 or 4 times the external clock's speed (e.g. a 16MHz CPU with a 4MHz bus). Later, more successful, enhancements to the Z80-architecture include Hitachi HD64180 and Zilog eZ80, among others. See further Zilog Z800.

External links

• mdfs.net - Z280 opcode list

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.