Editing Microcontroller (section)

== History ==
=== 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.

=== Development ===
One book credits [[Texas Instruments|TI]] engineers Gary Boone and Michael Cochran with the successful creation of the first microcontroller in 1971. The result of their work was the [[TMS 1000]], which became commercially available in 1974. It combined read-only memory, read/write memory, processor and clock on one chip and was targeted at embedded systems.<ref>{{cite book
 |chapter-url=http://smithsonianchips.si.edu/augarten/p38.htm
 |chapter=The Most Widely Used Computer on a Chip: The TMS 1000
 |title=State of the Art: A Photographic History of the Integrated Circuit
 |last=Augarten |first=Stan
 |publisher=Ticknor & Fields
 |location=New Haven and New York
 |year=1983
 |isbn=978-0-89919-195-9
 |access-date=2009-12-23
 |archive-url=https://web.archive.org/web/20100217065617/http://smithsonianchips.si.edu/augarten/p38.htm
 |archive-date=2010-02-17
 |url-status=dead
}}</ref>

During the early-to-mid-1970s, Japanese electronics manufacturers began producing microcontrollers for automobiles, including 4-bit MCUs for [[in-car entertainment]], automatic wipers, electronic locks, and dashboard, and 8-bit MCUs for engine control.<ref>{{cite web |title=Trends in the Semiconductor Industry |url=http://www.shmj.or.jp/english/trends/trd70s.html |website=Semiconductor History Museum of Japan |access-date=2019-06-27 |archive-url=https://web.archive.org/web/20190627082830/http://www.shmj.or.jp/english/trends/trd70s.html |archive-date=2019-06-27 |url-status=dead }}</ref>

Partly in response to the existence of the single-chip TMS 1000,<ref name=CMoral2008>{{cite web|url=http://archive.computerhistory.org/resources/access/text/2013/05/102658328-05-01-acc.pdf |title=Oral History Panel on the Development and Promotion of the Intel 8048 Microcontroller|work=Computer History Museum Oral History, 2008|access-date=2016-04-04|page=4}}</ref> Intel developed a computer system on a chip optimized for control applications, the [[Intel 8048]], with commercial parts first shipping in 1977.<ref name=CMoral2008/> It combined [[random-access memory|RAM]] and [[read-only memory|ROM]] on the same chip with a microprocessor. Among numerous applications, this chip would eventually find its way into over one billion PC keyboards. At that time Intel's President, Luke J. Valenter, stated that the microcontroller was one of the most successful products in the company's history, and he expanded the microcontroller division's budget by over 25%.

{{multiple image |total_width=420
 | image1   = PIC16CxxxWIN.JPG
 | caption1 = Various [[PIC microcontroller]]s with<br />integrated EPROM
 | image2   = Microcomputer with EPROM (piggyback).jpg
 | caption2 = Piggyback microcontroller from [[MOSTEK]]
}}

{{anchor|piggyback microcontroller}}
Most microcontrollers at this time had concurrent variants. One had [[EPROM]] program memory, with a transparent quartz window in the lid of the package to allow it to be erased by exposure to [[ultraviolet]] light. These erasable chips were often used for prototyping. The other variant was either a mask-programmed ROM or a [[Programmable read-only memory|PROM]] variant which was only programmable once. For the latter, sometimes the designation ''OTP'' was used, standing for "one-time programmable". In an OTP microcontroller, the PROM was usually of identical type as the EPROM, but the chip package had no quartz window; because there was no way to expose the EPROM to ultraviolet light, it could not be erased. Because the erasable versions required ceramic packages with quartz windows, they were significantly more expensive than the OTP versions, which could be made in lower-cost opaque plastic packages. For the erasable variants, quartz was required, instead of less expensive glass, for its transparency to ultraviolet light—to which glass is largely opaque—but the main cost differentiator was the ceramic package itself. '''Piggyback microcontrollers''' were also used.<ref>{{cite web |url=https://www.industrialalchemy.org/articleview.php?item=2028 |title=OKI Intel M85C154 Piggyback Microcontroller |website=industrialalchemy.org |access-date=2024-12-08}}</ref><ref>{{cite web |url=https://www.cpushack.com/2011/03/06/cpu-of-the-day-ns87p50r-6-piggyback-cpus/ |title=CPU of the Day: NS87P50R-6: Piggyback CPUs |website=cpushack.com |date=2011-03-06 |access-date=2024-12-08}}</ref><ref>{{cite web |url=https://www.allisdiy.com/main/piggyback-microcontroller |title=Piggyback microcontrollers |website=allisdiy.com |access-date=2024-12-08}}</ref>

In 1993, the introduction of [[EEPROM]] memory allowed microcontrollers (beginning with the Microchip [[PIC16x84|PIC16C84]])<ref name="pic16c84ref">{{cite web
 |url=https://spectrum.ieee.org/chip-hall-of-fame-microchip-technology-pic-16c84-microcontroller
 |title=Chip Hall of Fame: Microchip Technology PIC 16C84 Microcontroller
 |publisher=IEEE
 |access-date=September 16, 2018|date=2017-06-30
 }}</ref> to be electrically erased quickly without an expensive package as required for [[EPROM]], allowing both rapid prototyping, and [[in-system programming]]. (EEPROM technology had been available prior to this time,<ref name="mc68ch805ref">{{cite book |author=Motorola |title=Advance Information, 8-Bit Microcomputers MC68HC05B6, MC68HC05B4, MC68HC805B6, Motorola Document EADI0054RI |publisher=Motorola Ltd., 1988}}</ref> but the earlier EEPROM was more expensive and less durable, making it unsuitable for low-cost mass-produced microcontrollers.) The same year, Atmel introduced the first microcontroller using [[Flash memory]], a special type of EEPROM.<ref name="flash">{{cite web|title=Atmel's Self-Programming Flash Microcontrollers |url=https://ww1.microchip.com/downloads/en/DeviceDoc/doc2464.pdf |author=Odd Jostein Svendsli |date=2003 |access-date=2024-06-18}}</ref> Other companies rapidly followed suit, with both memory types.

Nowadays microcontrollers are cheap and readily available for hobbyists, with large online communities around certain processors.

=== Volume and cost ===
In 2002, about 55% of all [[central processing unit|CPU]]s sold in the world were 8-bit microcontrollers and microprocessors.<ref>{{Cite news|url=https://www.embedded.com/electronics-blogs/significant-bits/4024488/The-Two-Percent-Solution|title=The Two Percent Solution|last=Turley|first=Jim|work=Embedded|year=2002|access-date=2018-07-11|language=en}}</ref>

Over two billion 8-bit microcontrollers were sold in 1997,<ref>{{Cite web|url=https://www.circuitcellar.com/library/designforum/silicon_update/3/index.asp|archive-url=https://web.archive.org/web/20070927214629/https://www.circuitcellar.com/library/designforum/silicon_update/3/index.asp|archive-date=2007-09-27|url-status=dead|title=Microchip on the March <!--HTML title: Circuit Cellar - Digital Library-->|year=1998|first=Tom |last=Cantrell|website=Circuit Cellar|access-date=2018-07-11}}</ref> and according to Semico, over four billion 8-bit microcontrollers were sold in 2006.<ref>{{Cite web |url=https://www.semico.com |title=Semico Research}}</ref> More recently, Semico has claimed the MCU market grew 36.5% in 2010 and 12% in 2011.<ref>{{Cite web|url=https://semico.com/content/momentum-carries-mcus-2011|title=Momentum Carries MCUs Into 2011 {{!}} Semico Research|website=semico.com|language=en|access-date=2018-07-11}}</ref>

A typical home in a developed country is likely to have only four general-purpose microprocessors but around three dozen microcontrollers. A typical mid-range automobile has about 30 microcontrollers. They can also be found in many electrical devices such as washing machines, microwave ovens, and telephones.

{{blockquote|Historically, the 8-bit segment has dominated the MCU market [..] 16-bit microcontrollers became the largest volume MCU category in 2011, overtaking 8-bit devices for the first time that year [..] IC Insights believes the makeup of the MCU market will undergo substantial changes in the next five years with 32-bit devices steadily grabbing a greater share of sales and unit volumes.  By 2017, 32-bit MCUs are expected to account for 55% of microcontroller sales [..] In terms of unit volumes, 32-bit MCUs are expected account for 38% of microcontroller shipments in 2017, while 16-bit devices will represent 34% of the total, and 4-/8-bit designs are forecast to be 28% of units sold that year.

The 32-bit MCU market is expected to grow rapidly due to increasing demand for higher levels of precision in embedded-processing systems and the growth in connectivity using the Internet. [..] In the next few years, complex 32-bit MCUs are expected to account for over 25% of the processing power in vehicles.|IC Insights|MCU Market on Migration Path to 32-bit and ARM-based Devices<ref name="vol">{{cite web |url=http://www.icinsights.com/news/bulletins/MCU-Market-On-Migration-Path-To-32bit-And-ARMbased-Devices/
|date=April 25, 2013
|title=MCU Market on Migration Path to 32-bit and ARM-based Devices
|quote=It typically takes a global economic recession to upset the diverse MCU marketplace, and that's exactly what occurred in 2009, when the microcontroller business suffered its worst-ever annual sales decline of 22% to $11.1 billion.}}</ref>
}}

Cost to manufacture can be under {{US$|0.10}} per unit.

Cost has plummeted over time, with the cheapest [[8-bit computing|8-bit]] microcontrollers being available for under {{USD|0.03}} in 2018,<ref name=":0">{{Cite web|url=http://www.additude.se/bloggar/thomas-lovskog/the-really-low-cost-mcus/|title=The really low cost MCUs|website=www.additude.se|access-date=2019-01-16|archive-url=https://web.archive.org/web/20200803173013/http://www.additude.se/bloggar/thomas-lovskog/the-really-low-cost-mcus/|archive-date=2020-08-03|url-status=dead}}</ref> and some [[32-bit computing|32-bit]] microcontrollers around {{US$|1}} for similar quantities.

In 2012, following a global crisis—a worst ever annual sales decline and recovery and average sales price year-over-year plunging 17%—the biggest reduction since the 1980s—the average price for a microcontroller was {{US$|0.88}} ({{US$|0.69}} for 4-/8-bit, {{US$|0.59}} for 16-bit, {{US$|1.76}} for 32-bit).<ref name="vol"/>

In 2012, worldwide sales of 8-bit microcontrollers were around {{US$|4 billion}}, while [[4-bit computing|4-bit]] microcontrollers also saw significant sales.<ref>{{cite web |author=Bill Giovino |url=https://microcontroller.com/news/Zilog_Buys_Samsung_Microcontrollers.asp |title=Zilog Buys Microcontroller Product Lines from Samsung |date=June 7, 2013}}</ref>

In 2015, 8-bit microcontrollers could be bought for {{US$|0.311}} (1,000 units),<ref name="mouser.com">{{Cite web |url=https://www.mouser.com/ProductDetail/Silicon-Labs/EFM8BB10F2G-A-QFN20/?qs=sGAEpiMZZMu9ReDVvI6ax9sqO0qrXlDW4ZuhKcnb2c%252bQvyUXU1UbuQ%3d%3d |title=EFM8BB10F2G-A-QFN20 Silicon Labs &#124; Mouser}}</ref> 16-bit for {{US$|0.385}} (1,000 units),<ref name="ReferenceA">{{Cite web |url=https://www.mouser.com/ProductDetail/Texas-Instruments/MSP430G2001IPW14R/?qs=sGAEpiMZZMvfhsTlJjecML5mLnp8Cec4esZ6%2f1aK7FQ%3d |title = MSP430G2001IPW14R Texas Instruments &#124; Mouser}}</ref> and 32-bit for {{US$|0.378}} (1,000 units, but at {{US$|0.35}} for 5,000).<ref name="formerly_cheaper_32-bit">{{Cite web|title=CY8C4013SXI-400 Cypress Semiconductor {{!}} Mouser|website=Mouser Electronics|url=https://www.mouser.com/ProductDetail/Cypress-Semiconductor/CY8C4013SXI-400/?qs=sGAEpiMZZMuI9neUTtPr752e7iT1qQqS4inl2jxeWgxWqjKLOdzceQ==|archive-url=https://web.archive.org/web/20150218211453/https://www.mouser.com/ProductDetail/Cypress-Semiconductor/CY8C4013SXI-400/?qs=sGAEpiMZZMuI9neUTtPr752e7iT1qQqS4inl2jxeWgxWqjKLOdzceQ==|archive-date=2015-02-18|language=en-US}}</ref>

In 2018, 8-bit microcontrollers could be bought for {{US$|0.03}},<ref name=":0" /> 16-bit for {{US$|0.393}} (1,000 units, but at {{US$|0.563}} for 100 or {{US$|0.349}} for full reel of 2,000),<ref>{{Cite web |url=https://eu.mouser.com/ProductDetail/Texas-Instruments/MSP430FR2000IPW16R?qs=sGAEpiMZZMs0L%252b%252bydDbPCjJ%2f9huEtS8nFliXsvF0PDUDt%252bi%2fs4FH9A%3d%3d |title=MSP430FR2000IPW16R Texas Instruments &#124; Mouser}}</ref> and 32-bit for {{US$|0.503}} (1,000 units, but at {{US$|0.466}} for 5,000).<ref>{{Cite web |url=https://www.mouser.com/ProductDetail/Cypress-Semiconductor/CY8C4013SXI-400/?qs=sGAEpiMZZMuI9neUTtPr752e7iT1qQqS4inl2jxeWgxWqjKLOdzceQ== |title=CY8C4013SXI-400 Cypress Semiconductor {{!}} Mouser |website=Mouser Electronics|language=en-US|access-date=2018-07-11}}</ref>

In 2018, the low-priced microcontrollers above from 2015 were all more expensive (with inflation calculated between 2018 and 2015 prices for those specific units) at: the 8-bit microcontroller could be bought for {{US$|0.319}} (1,000 units) or 2.6% higher,<ref name="mouser.com"/> the 16-bit one for {{US$|0.464}} (1,000 units) or 21% higher,<ref name="ReferenceA"/> and the 32-bit one for {{US$|0.503}} (1,000 units, but at {{US$|0.466}} for 5,000) or 33% higher.<ref name="formerly_cheaper_32-bit"/>

[[Image:PIC18F8720.jpg|right|thumbnail|A [[PIC microcontroller|PIC]] 18F8720 microcontroller in an 80-pin [[Quad Flat Package|TQFP]] package]]

=== Smallest computer ===
On 21 June 2018, the "world's smallest computer" was announced by the [[University of Michigan]]. The device is a "{{val|0.04|ul=mm3}} {{val|16|ul=nW}} wireless and batteryless sensor system with integrated [[ARM Cortex-M#Cortex-M0+|Cortex-M0+]] processor and optical communication for cellular temperature measurement." It "measures just {{val|0.3|u=mm}} to a side—dwarfed by a grain of rice. [...] In addition to the RAM and [[photovoltaics]], the new computing devices have processors and [[wireless networking|wireless transmitters and receivers]]. Because they are too small to have conventional radio antennae, they receive and transmit data with visible light. A base station provides light for power and programming, and it receives the data."<ref>{{citation |url=https://news.umich.edu/u-m-researchers-create-worlds-smallest-computer/ |title=U-M researchers create world's smallest 'computer' |date=2018-06-21 |publisher=[[University of Michigan]]}}</ref> The device is {{frac|1|10}}th the size of IBM's previously claimed world-record-sized computer from months back in March 2018,<ref>{{citation |url=https://www.cnet.com/news/university-of-michigan-outdoes-ibm-with-worlds-smallest-computer/ |title=University of Michigan outdoes IBM with world's smallest 'computer' |date=2018-06-22 |publisher=[[CNET]]}}</ref> which is "smaller than a grain of salt",<ref>{{citation |url=https://www.cnet.com/news/ibm-fighting-counterfeiters-with-worlds-smallest-computer/ |title=IBM fighting counterfeiters with world's smallest computer |date=2018-03-19 |publisher=[[CNET]]}}</ref> has a million transistors, costs less than {{US$|long=no|0.10}} to manufacture, and, combined with [[blockchain]] technology, is intended for logistics and "crypto-anchors"—[[Fingerprint (computing)|digital fingerprint]] applications.<ref>{{citation |title=IBM Built a Computer the Size of a Grain of Salt. Here's What It's For. |date=2018-03-19 |publisher=[[Fortune (magazine)|Fortune]] |url=https://fortune.com/2018/03/19/ibm-computer-salt-grain-blockchain/}}</ref>