Zilog Z800 - Reason For The Failure

Reason For The Failure

The Z800 was, in most ways, a mini computer inspired "super Z80" that would run existing, and larger, programs at considerably higher speeds. However the address and data buses were multiplexed and the chip was, also in other respects, somewhat complicated to program and interface to. Calculation of exact execution times was also very much harder to do than for the Z80. Moreover, the plain Z80 were good enough for most applications at the time so the extra computing power was, in many cases, not worth the added complexity. Bad marketing seems to have hurt the product as well. Hitachi developed the HD64180, which is a less ambitious Z80 derivative that has had great success, probably because it is almost as simple to program and interface to as the original Z80. A slightly different variant of the same design, the Z180, has been sold by Zilog for over twenty years, still maintained and developed.