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Encyclopedia > Sinclair ZX80
Sinclair ZX80
Sinclair ZX80
Type Home computer
Released 1980
Discontinued 1981
Processor Z80 @ 3.25 MHz (most machines used the NEC μPD780C-1 equivalent)
Memory 1 KB (16 KB max.)
OS Sinclair BASIC

The Sinclair ZX80 was a home computer brought to market in 1980 by Sinclair Research of Cambridge, England. It was notable for being the first computer available in the United Kingdom for under a hundred pounds (a price tag of £99.95, to be exact). It was available in kit form, where purchasers had to assemble and solder it together, and as a ready-built version at a slightly higher cost for those without the skill or inclination to build their own unit. 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. Image File history File links ZX80. ... Children playing on a Amstrad CPC 464 in the 1980s. ... The Zilog Z80 is an 8-bit microprocessor designed and manufactured by Zilog from 1976 onwards. ... NEC Corporation is a multi-national information technologies company headquarterd in Minato-ku, Tokyo, Japan. ... Children playing on a Amstrad CPC 464 in the 1980s. ... Year 1980 (MCMLXXX) was a leap year starting on Tuesday (link displays the 1980 Gregorian calendar). ... Sinclair Research Ltd was a home computer company founded by Clive Sinclair in Cambridge, England. ... “GBP” redirects here. ...

Contents

Description

The machine was designed by Jim Westwood around a Z80 central processing unit with a clock speed of 3.25 MHz[1], and was equipped with 1 KB of static RAM and 4 KB of read-only memory containing the Sinclair BASIC programming language, editor, and operating system. BASIC commands were not entered by typing them out; instead, the commands were selected rather like they would be on a scientific calculator — each "key" had several different functions activated by use of several modifier (shift) keys. Jim Westwood was the chief engineer at Sinclair Research Ltd in the 1980s, starting at the company in 1963. ... The Zilog Z80 is an 8-bit microprocessor designed and manufactured by Zilog from 1976 onwards. ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... In synchronous digital electronics, such as most computers, a clock signal is a signal used to coordinate the actions of two or more circuits. ... A kilobyte (derived from the SI prefix kilo-, meaning 1000) is a unit of information or computer storage equal to the decimal 1024 bytes (2 to the 10th power, or 1,024 bytes based in the binary system). ... Static Random Access Memory (SRAM) is a type of semiconductor memory. ... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... Sinclair BASIC (taking its name from innovator Sir Clive Sinclair) is a dialect of the BASIC programming language used in the home computers from Sinclair Research and Timex Sinclair. ... A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. ... It has been suggested that Maintenance OS be merged into this article or section. ...


Display was over a RF connection to a household television, and simple offline program storage was possible using a cassette recorder. The video display generator of the ZX80 used minimal hardware plus a combination of software to generate a video signal. As a result of this approach the ZX80 could only generate a picture when it was idle, i.e. waiting for a key to be pressed. When running a BASIC program, or even when pressing as key for any input, the display would, therefore, black out momentarily to support the function. This made moving graphics difficult since the program had to introduce a pause for input to display the next change in graphical output. The later ZX81 improved on this somewhat because it could run in a 'slow' mode while creating a video signal, or in a 'fast' mode without generating a video signal (typically used for lengthy calculations). ZX81 logo The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the follow up to the companys ZX80. ...


A ZX81 8 KB ROM was available to upgrade the ZX80 and cost around 20% of a full blown ZX81. It came with a thin overlay keyboard and ZX81 manual. Simply taking off the top cover of the ZX80 and prying the old ROM from its socket and carefully inserting the new ROM and adding the keyboard overlay, the ZX80 (now ZX81) would now function almost identically to the proper ZX81 except for SLOW mode, and this was purely down to hardware differences. The process was easily reversed to get the ZX80 back to its old self. The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ...


Sinclair also produced RAM expansion packs for the ZX80; the original ZX80 RAM Pack held either 1, 2 or 3 KB, a later model held 16 KB, both were built around dynamic RAM chips (DRAM). There was no upgrade for the monochrome display however.


The machine was mounted in a tiny white plastic case, with a one-piece blue membrane keyboard on the front; it owed its distinctive appearance to industrial designer Rick Dickinson. There were problems with durability, reliability and over-heating. The entire system was about the size of two paperback books placed beside each other. Crude it might have been, but the ZX80 was a true innovator and it kick-started the 1980s home computer craze in the UK and New Zealand. It was superseded by a number of other Sinclair machines, notably the Sinclair ZX81 and the very successful ZX Spectrum. A membrane keyboard is a computer keyboard whose keys are not separate, moving parts, as with the majority of other keyboards, but rather have only outlines and symbols printed on a flat, flexible surface. ... Dickinson designed the ZX81 personal computer, and holds a patent for its design. ... ZX81 logo The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the follow up to the companys ZX80. ... The ZX Spectrum is a home computer released in the United Kingdom in 1982 by Sinclair Research Ltd. ...


Sales of the ZX80 reached about 50,000 — an unheard of number for the day which contributed significantly to the UK leading the world in home computer ownership through the 1980s. Owing to the unsophisticated design and the tendency for the units to overheat, surviving machines in good condition are quite uncommon and can fetch high prices by collectors.


Internal workings

The ZX80 was designed around TTL chips while the successor ZX81 used a semi-custom chip (an ULA or Uncommitted Logic Array), but these were superficial differences — the hardware and system programs (except the BASIC versions) were very similar, with the only significant difference being the NMI-generator necessary for slow mode in ZX81. See ZX81 for technical details. A Gate array or Uncommitted Logic Array (ULA) is an approach to the design and manufacture of application_specific integrated circuits (ASICS). ... The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ...


Different Flavors

There were also Americanized versions of the ZX80/ZX81 (Micro Ace / TS1000 respectively). An excellent list can be found at herr Liebert's ZX80/ZX81 User's Group web site (in Deutsch or English). The Sinclair ZX81 home computer, released by Sinclair Research in 1981, was the followup to the companys ZX80. ...


External links

footnotes

  1. ^ This frequency was critical, as the TV picture generation depended on it (see ZX81).
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Sinclair ZX80 computer (308 words)
British company Sinclair released their ZX80 computer in 1980 for $199.95.
It is considered to be the world's first computer for under $200, at least that's what Sinclair Research Ltd stated in all of their ads.
Sinclair sold 70,000 ZX80s before they came out with the improved ZX-81 one year later.
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