Editing Intel MCS-51 (section)

== Related processors ==
[[File:INTEL8031AH.png|thumb|right|Intel 8031 microcontrollers]]
[[File:Intel D87C51-3183.jpg|thumb|right|Intel D87C51 microcontroller]]

Intel discontinued its MCS-51 product line in March 2007;<ref>{{cite web |last1=Ganssle |first1=Jack |title=Intel bows out, discontinues MCS-51 |date=2006-05-29 |url=http://www.embedded.com/electronics-blogs/break-points/4025678/Intel-bows-out |archive-url=https://web.archive.org/web/20170813011859/http://www.embedded.com/electronics-blogs/break-points/4025678/Intel-bows-out |archive-date=2017-08-13 |url-status=dead}}</ref><ref>{{cite web |title=MCS 51, MCS 251 and MCS 96 Microcontroller Product Lines, the Intel 186, Intel386 and Intel486 Processors Product Lines, and the i960 32 Bit RISC Processor, PCN 106013-01, Product Discontinuance, Reason for Revision: Add Key Milestone information and revise description of change |publisher=Intel |date=2006-05-02 |url=http://qdms.intel.com/dm/d.aspx/7C715FEC-C598-444E-9EFB-2750B98F7956/PCN106013-01.pdf}}</ref> however, there are plenty of enhanced 8051 products or [[silicon intellectual property]] added regularly from other vendors.

The 8051's predecessor, the [[8048]], was used in the keyboard of the first [[IBM PC]], where it converted keypresses into the serial data stream which is sent to the main unit of the computer. An Intel 8049 served a similar role in the [[Sinclair QL]]. The 8048 and derivatives are still used {{As of|2007|alt=today}} for basic model keyboards.

The '''8031''' was a reduced version of the original 8051 that had no internal program ROM. To use this chip, external ROM had to be added containing the program that the 8031 would fetch and execute. An 8051 chip could be sold as a ROM-less 8031, as the 8051's internal ROM is disabled by the normal state of the EA pin in an 8031-based design. A vendor might sell an 8051 as an 8031 for any number of reasons, such as faulty code in the 8051's ROM, or simply an oversupply of 8051s and undersupply of 8031s.

[[File:Intel P8044AH.jpg|thumb|Intel P8044AH microcontroller]]
The '''8044''' (as well as the ROM-less 8344 and the 8744 with EPROM) added an [[Synchronous Data Link Control|SDLC]] controller to the 8051 core (especially for [[Bitbus]] applications).<ref>{{cite web |url=https://www.hoeben.com/bitbus.info/Intel_8044AH_8344AH.pdf |title=8044AH/8344AH/8744AH High Performance 8-bit Microcontroller with On-Chip Serial Communication Controller |publisher=Intel |date=October 1994}}</ref>

The '''8052''' was an enhanced version of the original 8051 that featured 256&nbsp;bytes of internal RAM instead of 128&nbsp;bytes, 8&nbsp;KB of ROM instead of 4&nbsp;KB, and a third 16-bit timer.  Most modern 8051-compatible microcontrollers include these features.

The '''8032''' had these same features as the 8052 except it lacked internal ROM program memory.

The '''8751''' was an 8051 with 4&nbsp;KB EPROM instead of 4&nbsp;KB ROM.  They were identical except for the non-volatile memory type.  This part was available in a ceramic package with a clear [[quartz]] window over the top of the die so [[Ultraviolet#Electrical and electronics industry|UV light]] could be used to erase the [[EPROM]].  Related parts are: 8752 had 8&nbsp;KB EPROM, 8754 had 16&nbsp;KB EPROM, 8758 had 32&nbsp;KB EPROM.

The '''80C537''' (ROM-less) and '''80C517''' (8 KB ROM)  are [[CMOS]] versions, designed for the [[automotive industry]]. Enhancements mostly include new and enhanced peripherals. The 80C5x7 has fail-safe mechanisms, analog signal processing facilities, enhanced timer capabilities, and a 32-bit arithmetic peripheral. Other features include:

* 256-byte on-chip RAM
* 256 directly addressable bits
* External program and data memory expandable up to 64&nbsp;KB
* 8-bit A/D converter with 12 multiplexed inputs
* Arithmetic peripheral can perform 16×16→32-bit multiplication, 32/16→16-bit division, 32-bit shift and 32-bit normalize operations
* Eight data pointers instead of one for indirect addressing of program and external data memory
* Extended watchdog facilities
* Nine I/O ports
* Two full-duplex serial interfaces with individual baud rate generators
* Four priority level interrupt systems, 14 interrupt vectors
* Three power-saving modes

<gallery mode="packed" heights="150px" caption="Intel MCS-51 [[second source]]s">
File:Intel_D87C51_AMD.jpg|[[AMD]] D87C51
File:MBL8031AH.jpg|[[Fujitsu]] MBL8031AH
File:Ic-photo-MHS--S-80C31--(8031-MCU).png|MHS S-80C31
File:Ic-photo-OKI--M80C31F--(8031-MCU).JPG|[[Oki Electric Industry|OKI]] M80C31
File:Ic-photo-Philips--80C31BH-3 16P--(8031-MCU).png|[[Philips]] PCB80C31
File:Ic-photo-Signetics--SCN8031H--(8031-MCU).JPG|[[Signetics]] SCN8031
File:Ic-photo-Temic--TS80C32X2-MCB-(8032-MCU).png|Temic TS80C32X2
</gallery>

=== Derivative vendors ===
More than 20 independent manufacturers produce MCS-51 compatible processors. {{citation needed|date=July 2017}}

<gallery mode="packed" heights="150px" caption="Intel MCS-51 derived microcontrollers">
File:Atmel 89c2051 gfdl.jpg|[[Atmel]] [[Atmel AT89 series|AT89C2051]]
File:SAB-C515-LN.jpg|[[Infineon]] SAB-C515
File:EPROM-Microcontroller Philips 87C654.jpg|[[Philips]] S87C654
File:Ic-photo-Siemens--SAB-C501G-1RP-(MCU).png|[[Siemens]] SAB-C501
File:STC89C52.jpg|STC Micro STC89C52
</gallery>

Other ICs or IPs compatible with the MCS-51 have been developed by [[Analog Devices]],<ref>{{cite web|url=http://www.analog.com/static/imported-files/data_sheets/ADUC832.pdf|access-date=30 April 2023|website=analog.com|title=MicroConverter, 12-Bit ADCs and DACs with Embedded 62 kB Flash MCU|archive-date=28 May 2014|archive-url=https://web.archive.org/web/20140528075220/http://www.analog.com/static/imported-files/data_sheets/ADUC832.pdf|url-status=dead}}</ref> Integral [[Minsk]],<ref name=integral>{{cite web
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| trans-title=Microcontrollers and Power Supervisors Series 1880; 1881; 1842; 588; 1345; 5518AP1TBM
| publisher=OAO "Integral"
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Kristall [[Kyiv]],<ref name=kristall5701>{{cite web
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 |trans-title=Single-chip microcomputers 
 |publisher=Kristall 
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 |url=http://krystall.net.ua/ru/products/53.html 
 |archive-url=https://web.archive.org/web/20120530003614/http://krystall.net.ua/ru/products/53.html 
 |archive-date=30 May 2012 
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NIIET [[Voronezh]].<ref name=niiet>{{cite web
| title=Микроконтроллеры
| trans-title=Microcontrollers
| publisher=OAO "NIIET"
| place=Voronezh
| url=http://niiet.ru/goods/chips/microcont
| language=ru
| access-date=22 August 2017
| archive-url=https://web.archive.org/web/20170822175635/http://niiet.ru/goods/chips/microcont
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