MK14
segment display | |
Input | 20 key keyboard |
---|---|
Successor | ZX80 |
The MK14 (Microcomputer Kit 14) was a
History
Design
From 1974, Ian Williamson was working at the engineering firm Cambridge Consultants Ltd (CCL) where he repeatedly tried to interest the firm in producing
Williamson decided to design his own version to address these issues. National had an evaluation system known as the IntroKit that included the SC/MP processor, 256 bytes of
By this time, in the spring of 1977, Williamson was offered a job at British Leyland, which he accepted. He approached the managers at CCL to take on production of his computer design, but they were uninterested. This led naturally to Sinclair, who already made the calculator he was using and had a long history in selling kits.[3]
Sinclair
Sinclair Radionics had been nationalized and Clive Sinclair was losing control of the company. In 1976 he set up Science of Cambridge (originally as Sinclair Instruments) to recreate Radionics' early mail-order kit success. He handed the company to Chris Curry, who ran the company single-handedly. Their first product was the kit-form Sinclair Wrist Calculator which was moderately successful but relatively low quality. When Williamson approached Sinclair and Curry, they both liked the idea and saw the potential of selling this more advanced kit into the hobby market.[4]
When Curry approached National inquiring about costs for a mass purchase of the SC/MP, National countered by offering them a completely developed computer system based entirely on National's parts. The design combined National's SC/MP Introkit and Keyboard Kit and they offered the resulting design for free, along with some basic software, in exchange for a contract for the parts. Sinclair decided this was a far better deal than what he could arrange using Williamson's design, and Williamson was cut out of further development. Williamson would later be paid £2,000, ostensibly for writing a manual.[4]
It was put on the market at £39.95 plus £3.20 VAT and 40 pence postage and handling. They placed an initial order with National for 2,000 sets, but the low cost resulted in early orders for 20,000. The first systems began to arrive in February 1978, but real production quantities did not begin to arrive for another three months.[5] According to Curry, about 15,000 were sold in total.[4] The name apparently refers to its fourteen components.[6]
Specification
The computer is based around
The on-board RAM could be increased in two ways; by the addition of an INS8154N RAM/IO chip providing an additional 128 bytes of RAM along with 16 I/O lines, and also a further 256 bytes by adding two 256 × 4 bit RAM chips giving a maximum of 640 bytes on board. These memory spaces were not contiguous in the memory map. It was possible to connect off-board RAM giving a 2170 bytes total.[7]
See also
References
Citations
- ^ "Planet Sinclair: Computers: MK 14: Articles: PE 5/79". www.nvg.ntnu.no.
- ^ Smith 2014.
- ^ a b c Smith 2014, p. 1.
- ^ a b c Smith 2014, p. 2.
- ^ McAlpine 2018, p. 37.
- ISBN 9781529394078.
- ^ a b Owen.
Bibliography
- Owen, Chris. "Planet Sinclair: Computers: MK 14 Specifications". rk.nvg.ntnu.no.
- McAlpine, Kenneth (2018). Bits and Pieces: A History of Chiptunes. Oxford University Press. ISBN 978-0-19-049612-8.
- Smith, Tony (16 January 2014). "Ian Williamson: The engineer who gave Sinclair his first micro". The Register.
External links
- Old-computers.com dedicated page, article, pictures, documents and videos
- 1978's Raspberry Pi (MK14) - Computerphile
- MK14 manual
- The Sinclair / Science of Cambridge MK14 Web Site, includes emulator software
- Making a reproduction MK14 – includes original manuals/schematics