MOS Technology

MOS Technology, Inc was a microprocessor manufacturing company most famous for its creation of the 6502 processor.

The 6502 was used as the main CPU (Central Processing Unit) in many computers and game consoles during the late 1970s and early-to-mid-1980s. An incomplete list of machines that were built around the 6502 include:

Home Computers
Acorn Electron/BBC Microcomputer
Apple II
Commodore PET
Commodore VIC-20
Commodore 64

Game consoles
Atari 2600
Nintendo Entertainment System (or NES)

 

Company History

The company's original target market and purpose was to provide a second source for Texas Instruments designed electronic calculators and the chips inside them.

Fortunes for the company changed dramatically in 1975. A group of designers from the Motorola 6800 team left the company in a mass exodus shortly after its release. "As Motorola publicly unveiled the 6800, Chuck Peddle and seven coworkers from the engineering and marketing department left Motorola to pursue their own vision. The team included Will Mathis, Bill Mensch, Rod Orgill, Ray Hirt, Harry Bawcum, Mike James and Terry Holt." MOS was a small firm with good credentials in the right area, the East coast of the USA, and this was the luckiest windfall the company had yet received.

At MOS the team set about building a new CPU that would outperform the 6800 while being similar to it in purpose. The resulting 6501 design was somewhat similar to the 6800, but by using several simplifications in the design, the 6501 would be up to four times faster.

Controversy

When the 6501 was released, Motorola filed suit against MOS almost immediately. The 6501 was pin compatible with Motorola's 6800 (meaning it could fit in the same board socket), however its instruction set was different. Nevertheless, MOS Technology changed the processor's design to avoid being sued. The 'lawsuit-friendly' 6502 (which was neither pin-compatible nor instruction-set compatible) was the result.

See Also

• Central Processing Unit