Editing MOS Technology 6502 (section)

===Origins at Motorola===
[[File:Motorola 6800 proto board.jpg|thumb|Motorola 6800 demonstration board built by Chuck Peddle and John Buchanan in 1974]]

The 6502 was designed by many of the same engineers that had designed the [[Motorola 6800]] microprocessor family.<ref name="MD Dec 1975 6502 Law Suit">{{Cite journal |title=Motorola Sues MOS Technology |journal=Microcomputer Digest |volume=2 |issue=6 |page=11 |publisher=Microcomputer Associates |location=Cupertino CA |date=December 1975 |url=http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n06_Dec75.pdf |archive-url=https://web.archive.org/web/20090704150106/http://www.bitsavers.org/pdf/microcomputerAssociates/Microcomputer_Digest_v02n06_Dec75.pdf |url-status=dead |archive-date=July 4, 2009}}</ref> Motorola started the 6800 microprocessor project in 1971 with Tom Bennett as the main architect. Motorola's engineers could run analog and digital simulations on an [[IBM System/370|IBM 370-165]] mainframe computer.<ref name="MOS Modeling">{{Cite journal |last=Jenkins |first=Francis |author2=Lane, E. |author3=Lattin, W. |author4=Richardson, W. |title=MOS-device modeling for computer implementation |journal=IEEE Transactions on Circuit Theory| volume=20 |issue=6 |pages=649–658 |publisher=IEEE |date=November 1973 |issn=0018-9324 |doi=10.1109/tct.1973.1083758}} All of the authors were with Motorola's Semiconductor Products Division.</ref> The chip layout began in late 1972, the first 6800 chips were fabricated in February 1974 and the full family was officially released in November 1974.<ref name="MC6800 March 1974">{{Cite journal |title=Motorola joins microprocessor race with 8-bit entry |journal=Electronics |volume=47 |issue=5 |pages=29–30 |publisher=McGraw-Hill |location=New York |date=March 7, 1974}}</ref><ref>Motorola 6800 Oral History (2008), p. 9</ref> 

John Buchanan was the designer of the 6800 chip<ref name="Buchanan 3942047">{{Cite patent|number=US3942047A|title=MOS DC Voltage booster circuit|gdate=1976-03-02|invent1=Buchanan|inventor1-first=John K.|url=https://patents.google.com/patent/US3942047A/en}} {{Webarchive|url=https://web.archive.org/web/20240213150624/https://patents.google.com/patent/US3942047A/en |date=2024-02-13 }}</ref><ref name="Buchanan 3987418">{{Cite patent|number=US3987418A|title=Chip topography for MOS integrated circuitry microprocessor chip|gdate=1976-10-19|invent1=Buchanan|inventor1-first=John K.|url=https://patents.google.com/patent/US3987418A/en}} {{Webarchive|url=https://web.archive.org/web/20240213150626/https://patents.google.com/patent/US3987418A/en |date=2024-02-13 }}</ref> and Rod Orgill, who later did the 6501, assisted Buchanan with circuit analyses and chip layout.<ref>Motorola 6800 Oral History (2008), p. 8</ref> [[Bill Mensch]] joined Motorola in June 1971 after graduating from the University of Arizona (at age 26).<ref>Mensch Oral History (1995) Mensch earned an Associate degree from Temple University in 1966 and then worked at Philco Ford as an electronics technician before attending the University of Arizona.</ref> His first assignment was helping define the peripheral ICs for the 6800 family and later he was the principal designer of the 6820 [[Peripheral Interface Adapter]] (PIA).<ref name="Mensch 3968478">{{Cite patent|number=US3968478A|title=Chip topography for MOS interface circuit|gdate=1976-07-06|invent1=Jr|inventor1-first=William D. Mensch|url=https://patents.google.com/patent/US3968478A/en}} {{Webarchive|url=https://web.archive.org/web/20240213150625/https://patents.google.com/patent/US3968478A/en |date=2024-02-13 }}</ref> Bennett hired [[Chuck Peddle]] in 1973 to do architectural support work on the 6800 family products already in progress.<ref name="EDN Oct 27 1988">{{cite journal |last=Donohue |first=James F.| title=The microprocessor first two decades: The way it was |journal=EDN |volume=33 |issue=22A |pages=18–32 |publisher=Cahners Publishing |date=October 27, 1988 |issn=0012-7515}} Page 30. Bennett already was at work on what became the 6800. "He hired me," Peddle says of Bennett, "to do the architectural support work for the product he'd already started." … Peddle says. "Motorola tried to kill it several times. Without Bennett, the 6800 would not have happened, and a lot of the industry would not have happened, either."</ref> He contributed in many areas, including the design of the 6850 ACIA (serial interface).<ref name="Peddle 3968478">{{Cite patent|number=US3975712A|title=Asynchronous communication interface adaptor|gdate=1976-08-17|invent1=Hepworth|invent2=Means|invent3=Peddle|inventor1-first=Edward C.|inventor2-first=Rodney J.|inventor3-first=Charles I.|url=https://patents.google.com/patent/US3975712A/en}} {{Webarchive|url=https://web.archive.org/web/20240213150626/https://patents.google.com/patent/US3975712A/en |date=2024-02-13 }}</ref>

Motorola's target customers were established electronics companies such as [[Hewlett-Packard]], [[Tektronix]], [[TRW Inc.|TRW]], and [[Chrysler]].<ref name="M6800 TRW HP RUSCO">{{Cite journal |last=Motorola |title=They stay out front with Motorola's M6800 Family |journal=Electronics |volume=49 |issue=16 |page=51 |publisher=McGraw-Hill |date=August 5, 1976 |url=http://commons.wikimedia.org/wiki/File:Motorola_MC6800_microprocessor_ad_August_1976.jpg |access-date=June 4, 2012 |archive-date=January 10, 2014 |archive-url=https://web.archive.org/web/20140110190436/http://commons.wikimedia.org/wiki/File:Motorola_MC6800_microprocessor_ad_August_1976.jpg |url-status=live}} Advertisement showing three embedded applications from TRW, HP and RUSCO.</ref> In May 1972, Motorola's engineers began visiting select customers and sharing the details of their proposed 8-bit microprocessor system with ROM, RAM, parallel and serial interfaces.<ref>Motorola 6800 Oral History (2008), p. 89</ref> In early 1974, they provided engineering samples of the chips so that customers could prototype their designs. Motorola's "total product family" strategy did not focus on the price of the microprocessor, but on reducing the customer's total design cost. They offered development software on a timeshare computer, the "EXORciser" debugging system, onsite training and field application engineer support.<ref name="Electronics Jan 1975">{{Cite journal |title=It's the total product family |journal=Electronics |volume=48 |issue=1 |page=37 |url=http://commons.wikimedia.org/wiki/File:Motorola_6800_Total_Product_Family_1975.jpg |publisher=McGraw Hill |location=New York |date=January 9, 1975 |access-date=June 4, 2012 |archive-date=November 11, 2012 |archive-url=https://web.archive.org/web/20121111004455/http://commons.wikimedia.org/wiki/File:Motorola_6800_Total_Product_Family_1975.jpg |url-status=live}} Motorola advertisement emphasizing their complete set of peripheral chips and development tools. This shortened the customer's product design cycle.</ref><ref>Motorola 6800 Oral History (2008) p. 18</ref> Both Intel and Motorola had initially announced a {{US$|360}} price for a single microprocessor.<ref name="MC6850 1975">{{Cite journal |title=Motorola microprocessor set is 1 MHz n-MOS |journal=Control Engineering |volume=21 |issue=11 |page=11 |date=November 1974}} MC6800 microprocessor price was $360. The MC6850 asynchronous communications interface adaptor (ACIA) was slated for first quarter 1975 introduction.</ref><ref name="Intel $360">{{cite book |editor-first=Glynnis Thompson |editor-last=Kaye |title=A Revolution in Progress: A History to Date of Intel |publisher=Intel Corporation |year=1984 |page=14 |url=http://www.intel.com/Assets/PDF/General/15yrs.pdf |id=Order number:231295 |url-status=dead |access-date=30 December 2016 |archive-url=https://web.archive.org/web/20121023005651/http://www.intel.com/Assets/PDF/General/15yrs.pdf |archive-date=23 October 2012}} "Shima implemented the 8080 in about a year and the new device was introduced in April 1974 for $360."</ref> The actual price for production quantities was much less. Motorola offered a design kit containing the 6800 with six support chips for {{US$|300}}.<ref name="Electronics April 17, 1975">{{Cite journal |title=Motorola mounts M6800 drive |journal=Electronics |volume=48 |issue=8 |page=25 |publisher=McGraw-Hill |location=New York |date=April 17, 1975}} "Distributors are being stocked with the M6800 family, and the division is also offering an introductory kit that includes the family's six initial parts, plus applications and programming manuals, for $300."</ref>

Peddle, who would accompany the salespeople on customer visits, found that customers were put off by the high cost of the microprocessor chips.{{sfn|Interview|2014|loc=52:30}} At the same time, these visits invariably resulted in the engineers he presented to producing lists of required instructions that were much smaller than "all these fancy instructions" that had been included in the 6800.{{sfn|Interview|2014|loc=54:45}} Peddle and other team members started outlining the design of an improved feature, reduced-size microprocessor. At that time, Motorola's new semiconductor fabrication facility in [[Austin, Texas]], was having difficulty producing MOS chips, and mid-1974 was the beginning of a year-long recession in the semiconductor industry. Also, many of the [[Mesa, Arizona]] employees were displeased with the upcoming relocation to Austin.<ref>Bagnall (2010), p. 11. Peddle's new offer came at an opportune time for the 6800 developers. "They didn't want to go to Austin, Texas," explains Mensch.</ref>

Motorola's Semiconductor Products Division management showed no interest in Peddle's low-cost microprocessor proposal. Eventually, Peddle was given an official letter telling him to stop working on the system.{{sfn|Interview|2014|loc=54:40}} Peddle responded to the order by informing Motorola that the letter represented an official declaration of "project abandonment", and as such, the intellectual property he had developed to that point was now his.{{sfn|Interview|2014|loc=55:50}} In a November 1975 interview, Motorola's Chairman, Robert Galvin, ultimately agreed that Peddle's concept was a good one and that the division missed an opportunity, "We did not choose the right leaders in the Semiconductor Products division." The division was reorganized and the management replaced. The new group vice president John Welty said, "The semiconductor sales organization lost its sensitivity to customer needs and couldn't make speedy decisions."<ref name="Electronics Nov 13 1975">{{Cite journal |last=Waller |first=Larry |title=Motorola seeks to end skid |journal=Electronics |volume=48 |issue=23 |pages=96–98 |publisher=McGraw-Hill |location=New York |date=November 13, 1975}} Summary: Semiconductor Products split into two parts, integrated circuits and discrete components. Semiconductor losses for the last four quarters exceeded $30 million. The sales organization lost its sensitivity to customer needs, "delays in responding to price cuts meant that customers bought elsewhere." Technical problems plagued IC production. The troubles are "not in design, but in chip and die yields." Problems have been solved. The MC6800 microprocessor "arrived in November 1974."</ref>