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Sinclair ZX80

ZX80
ZX80.jpg
Type Home computer
Release date 1980; 37 years ago (1980)
Introductory price £99.95 (£387; $591 at 2017 prices)
Discontinued 1981
Units shipped 100,000
Media Cassette tape
Operating system Sinclair BASIC
CPU Z80 @ 3.25 MHz (most machines used the NEC μPD780C-1 equivalent)
Memory 1 KB (16 KB max.)
Successor ZX81

The Sinclair ZX80 is a home computer brought to market in 1980 by Science of Cambridge Ltd. (later to be better known as Sinclair Research). It is notable for being the first computer (unless one counts the MK14) available in the United Kingdom for less than a hundred pounds. It was available in kit form for £79.95, where purchasers had to assemble and solder it together, and as a ready-built version at £99.95. The ZX80 was very popular straight away, and for some time there was a waiting list of several months for either version of the machine.

The ZX80 was named after the Z80 processor with the 'X' for "the mystery ingredient".

Internally, the machine was designed by Jim Westwood around a Z80 central processing unit with a clock speed of 3.25 MHz, and was equipped with 1 KB of static RAM and 4 KB of read-only memory (ROM). The ZX80 was designed around readily available TTL chips; the only proprietary technology was the firmware. The successor ZX81 used a semi-custom chip (a ULA or Uncommitted Logic Array) which combined the functions of much of the earlier hardware onto a single chip reducing the chip-count from 21 to 4. However this was mainly a cost-reduction effort; the hardware functionality and system programs were very similar, with the only significant difference being the NMI-generator necessary for slow mode in the ZX81 (see ZX81 for technical details), and the 4K integer-only Sinclair BASIC upgraded to 8K floating-point-capable, with the upgraded ROM also available as upgrade for the ZX80. Both computers can be made by hobbyists using commercially available discrete logic chips or FPGAs.


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