Editing Microcontroller (section)

=== Background ===
{{Further|MOS integrated circuit|Microprocessor chronology}}

The first multi-chip microprocessors, the [[Four-Phase Systems AL1]] in 1969 and the [[Garrett AiResearch]] [[MP944]] in 1970, were developed with multiple MOS LSI chips. The first single-chip microprocessor was the [[Intel 4004]], released on a single MOS LSI chip in 1971. It was developed by [[Federico Faggin]], using his [[silicon-gate]] MOS technology, along with [[Intel]] engineers [[Marcian Hoff]] and [[Stan Mazor]], and [[Busicom]] engineer [[Masatoshi Shima]].<ref>{{cite web |title=1971: Microprocessor Integrates CPU Function onto a Single Chip |website=The Silicon Engine |url=https://www.computerhistory.org/siliconengine/microprocessor-integrates-cpu-function-onto-a-single-chip/ |publisher=[[Computer History Museum]] |access-date=22 July 2019}}</ref> It was followed by the [[4-bit computing|4-bit]] [[Intel 4040]], the [[8-bit computing|8-bit]] [[Intel 8008]], and the 8-bit [[Intel 8080]]. All of these processors required several external chips to implement a working system, including memory and peripheral interface chips. As a result, the total system cost was several hundred (1970s US) dollars, making it impossible to economically computerize small appliances.

[[MOS Technology]] introduced its sub-$100 microprocessors in 1975, the 6501 and [[MOS Technology 6502|6502]]. Their chief aim was to reduce this cost barrier but these microprocessors still required external support, memory, and peripheral chips which kept the total system cost in the hundreds of dollars.