MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a semiconductor design and fabrication company based in Audubon, Pennsylvania. It is most famous for its 6502 microprocessor and various designs for Commodore International's range of home computers.
A 1973 MOS Technology advertisement highlighting their custom integrated circuit capabilities
Image of the circuit board of a Commodore 64 showing some important MOS Technology circuits: the 6510 CPU (long chip, lower left) and the 6581 SID (right). The production week/year (WWYY) of each chip is given below its name.
The MOS Technology 6502 is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design.
A MOS Technology 6502 processor in a DIP-40 plastic package. The four-digit date code indicates it was made in the 45th week (November) of 1985.
Motorola 6800 demonstration board built by Chuck Peddle and John Buchanan in 1974
A 1973 MOS Technology advertisement highlighting their custom integrated circuit capabilities
MOS Technology MCS6501, in white ceramic package, made in late August 1975