Acorn  System 1
Previous System
Next System

The Acorn System 1 or the Acorn Micro-Computer

The Acorn System 1 was an early 8-bit computer kit for hobbyists. It was based on the MOS 6502 Architecture and manufactured by Acorn starting 1979. The main design was done by the Cambridge-undergraduate student Sophie Wilson, and the cassette interface was designed by Steve Furber. This was Acorn's first computer.


  • Seven segment LED display
  • 25 hexadecimal and function keys
  • Cassette CUTS interface
  • 6502 CPU running at 1MHz
  • INS8154 RAMIO integrated circuit
  • 2x2114 1024x4 RAM chips
  • 2x74S571 512x4 PROM chip
  • Optional INS8154 RAMIO Expansion Chip
  • Socket for optional additional ROM or EEPROM
  • 7.5V external power supply, 5V on-board regulator
  • Two stacked circuit boards connected by a semi-flexible multi-conductor cable (Spectra Strip)

MOS 6502 CPU

The 6502 is an 8-bit MicroProcessor designed by MOS Technology. The team was led by Chuck Peddle and had also worked on the Motorola 6800. The 6502 is a simplified, but faster and cheaper design than the 6800.

The 6502 was introduced in 1975 and was the cheapest microprocessor on the market. Together with the Zilog Z80, the 6502 helped start the home computer revolution of the 1980s. The 6502 was used in a wide range of devices: the Atari 2600, the 8-bit Atari home computers, the Apple II, the Nintendo Entertainment System, the Commodore 64, the BBC Micro and many others. All used the 6502 or a variation of it.

The 6502 is a 1MHz design, while the 6502A is designed for 2MHz. The 6502A is 100% compatible with the original 6502.

Commodore soon bought MOS Technology, but conitnued to sell the microprocessor to competitors and licensed the design to other manufacturers.

Source: WikiPedia - MOS Technology 6502
Technical Details
Released 1979 Brand Acorn Computers Ltd. Type Acorn System Name System 1 CPU Class 6502 CPU MOS 6502 @1MHz Memory RAM: 1152 Bytes Sound Chip none Sound 1 channel internal speaker Display Chip none Display LED Best Text none Best Color none Best Graphics none Sprites none System OS BASIC Storage External Tape Original Price £65
Related Systems
Acorn System
System  1 (1979)
Acorn Business Computer
Acorn BBC/Acorn 8-bit
Acorn Archimedes 300/400
Acorn New Archimedes 400s
Acorn Workstations
Acorn Archimedes 3000+
Related Media
6502 CPU
Collection of books on the 6502 and compatible CPUs
Acorn / BBC
Acorn Programs Magazine is a British publication covering news, listings, and programming advice for the BBC and Acorn computers.
Acorn User
A magazine covering the early BBC computers to later the Acorn ARM machines.
The 6502/6809 Journal
Acorn / BBC
Acorn Technical and Service Manuals
World Wide Web Links
MOS 6502 CPU Wiki Page
The 6502 is an 8-bit MicroProcessor designed by MOS Technology.