MOS 6501

The MOS Technology MCS6501, also simply referred to as 6501, was a low-cost 8-bit processor that was briefly produced by . However, it was overshadowed by its widely-adopted successor, the MOS 6502.
==History==
Electrical engineer had worked on the processor in 1973, which was priced at 300 per unit in a kit. Motorola turned down his proposal to produce a simplified processor to meet marketplace demand for a lower-cost processor. Peddle and some other Motorola engineers then left for MOS Technology, where they formed a small team to design the MOS 6501 and 6502, which became available in 1975 at a fraction of the cost of the Motorola 6800 and .
In November 1975, Motorola filed a lawsuit against MOS Technology for patent infringement and misappropriation of trade secrets."Motorola said last week it would seek an immediate injunction to stop MOS Technology Inc., Norristown, Pa., from making and selling microprocessor products, including its MCS6500." (This issue was published on November 7.) MOS settled the case in March 1976 for $200,000 and cancelling the 6501 processor, which was socket-compatible with the 6800. "MOS Technology Inc. of Norristown, Pa. has agreed to withdraw its MCS6501 microprocessor from the market and to pay Motorola Inc. $200000 ..." "MOS Technology and eight former Motorola employees have given back, under court order documents that Motorola contends are confidential." "…both companies have agreed to a cross license relating to patents in the microprocessor field." In November 1976, MOS was acquired by , which produced the 6502 and variants for its own computer line." Commodore International … is buying MOS Technology (Norristown, PA). This saves the six-year-old semiconductor house from impending disaster."
Steve Wozniak obtained early units of the 6501 for use in the Apple Computer A prototype. For production units of the Apple-1 computer that shipped in 1976, Wozniak said that the processor was switched from the 6501 to the 6502 with its improved transistors because "by real production time we could get the 6502 for the same cost".Historic photos reveal new details about Apple’s first prototype by Ed Hardy, Cult of Mac. 2022-03-29.
==References==
==External links==
*6501 at Retro Computing
*MOS Technology MCS6501 Processor at The CPU Shack Museum
* at Wikipedia
Category:Microprocessors
Category:1975 introductions