Editing Atari 2600 (section)

===MOS Technology 6502/6507===
In September 1975, [[MOS Technology]] debuted the [[MOS Technology 6502|6502 microprocessor]] for {{US$|25|long=no}} at the Wescon trade show in San Francisco.<ref name = Comp1975>{{Cite journal | title = MOS 6502 the second of a low cost high performance microprocessor family | journal = Computer | volume = 8 | issue = 9 | pages = 38–39 | publisher = IEEE Computer Society | date = September 1975 | url = http://commons.wikimedia.org/wiki/File:MOS_6501_6502_Ad_Sept_1975.jpg | doi = 10.1109/C-M.1975.219074 | access-date = September 28, 2020 | archive-date = February 24, 2021 | archive-url = https://web.archive.org/web/20210224154043/https://commons.wikimedia.org/wiki/File:MOS_6501_6502_Ad_Sept_1975.jpg | url-status = live }}</ref><ref name="atari fun chp5"/> Mayer and Milner attended, and met with the leader of the team that created the chip, [[Chuck Peddle]]. They proposed using the 6502 in a game console, and offered to discuss it further at Cyan's facilities after the show.<ref name=edge/>

Over two days, MOS and Cyan engineers sketched out a 6502-based console design by Meyer and Milner's specifications.<ref name="ieee decuir">{{cite journal |title = Atari Video Computer System: Bring Entertainment Stories Home | first = Joe | last = Decuir | journal = IEEE Consumer Electronics Magazine | date = July 2015 | doi = 10.1109/MCE.2015.2421572 | pages =59–66 | doi-access = free }}</ref> Financial models showed that even at {{USD|25|long=no}}, the 6502 would be too expensive, and Peddle offered them a planned [[MOS Technology 6507|6507 microprocessor]], a cost-reduced version of the 6502, and MOS's [[MOS Technology 6532|RIOT]] chip for [[input/output]]. Cyan and MOS negotiated the 6507 and RIOT chips at {{USD|12|long=no}} a pair.<ref name=edge/><ref>Oral History of Chuck Peddle.  Computer History Museum  X7180.2014  https://www.computerhistory.org/collections/catalog/102739938 {{Webarchive|url=https://web.archive.org/web/20210611034012/https://www.computerhistory.org/collections/catalog/102739938 |date=June 11, 2021 }}  https://www.youtube.com/watch?v=enHF9lMseP8 {{Webarchive|url=https://web.archive.org/web/20210611034818/https://www.youtube.com/watch?v=enHF9lMseP8 |date=June 11, 2021 }}  time index: 0:59:10 and 1:19:24</ref> MOS also introduced Cyan to [[Microcomputer Associates, Incorporated|Microcomputer Associates]], who had separately developed debugging software and hardware for MOS, and had developed the JOLT Computer for testing the 6502, which Peddle suggested would be useful for Atari and Cyan to use while developing their system.<ref name="atari fun chp5"/> Milner was able to demonstrate a proof-of-concept for a programmable console by implementing ''[[Tank (video game)|Tank]]'', an arcade game by Atari's subsidiary [[Kee Games]], on the JOLT.<ref name="atari fun chp5"/>

As part of the deal, Atari wanted a second source of the chipset. Peddle and Paivinen suggested [[Synertek]] whose co-founder, Bob Schreiner, was a friend of Peddle.<ref name="gamespy history p. 1"/> In October 1975, Atari informed the market that it was moving forward with MOS. The Motorola sales team had already told its management that the Atari deal was finalized, and Motorola management was livid. They announced a lawsuit against MOS the next week.<ref name=edge/>