Editing Intel MCS-48 (section)

== Uses ==
The MCS-48 series was commonly used in computer and terminal keyboards, converting key presses into protocols that can be understood by digital circuits. This also allows the possibility of serial communication, reducing the amount of conductors needed in cables on external keyboards. Microprocessors had been used in keyboards since at least 1972, simplifying earlier discrete designs. The 8048 has been used in this application since its introduction in 1978.{{cn|date=March 2023}}

The Tandy/Radio Shack [[TRS-80 Model II]], released in 1979, used the 8021 in its keyboard.<ref>{{cite book |title=TRS-80 Model II Technical Reference Manual |publisher=Radio Shack |page=135}}</ref> The 8021 processor scans the key matrix, converts switch closures to an 8-bit code and then transmits that code serially to the keyboard interface on the main system. It will also accept commands to turn indicator LEDs on or off. The 8021 was also used in the keyboards for the TRS-80 Model 12, 12B, 16, 16B and the Tandy 6000/6000HD.<ref>{{cite book |title=Tandy 6000/6000HD Service Manual |date=1985 |publisher=Tandy/Radio Shack |page=213}}</ref>

The original [[IBM PC keyboard]] used an 8048 as its internal [[microcontroller]].<ref>{{Citation |title=Technical Reference: Personal Computer |series=Personal Computer Hardware Reference Library |chapter=Section 4: Keyboard |publisher=[[IBM]] |date=April 1984 |edition=Revised}}</ref> The [[IBM Personal Computer/AT|PC AT]] replaced the PC's [[Intel 8255]] peripheral interface chip at I/O port addresses {{mono|[[hexadecimal|0x]]60–63}} with an 8042 accessible through port addresses {{mono|0x60}} and {{mono|0x64}}.<ref>{{Citation |title=Technical Reference: Personal Computer AT |series=Personal Computer Hardware Reference Library |chapter=Section 1: System Board |publisher=IBM |date=September 1985}}</ref> As well as managing the keyboard interface, the 8042 controlled the [[A20 line]] gating function for the AT's [[Intel 80286]] CPU and could be commanded by software to reset the 80286 (unlike the [[Intel 80386|80386]] and later processors, the 80286 had no way of switching from [[protected mode]] back to [[real mode]] except by being reset). Later PC compatibles integrate the 8042's functions into their [[super I/O]] devices.

The 8048 was used in the [[Magnavox Odyssey²]] [[video game console]], the [[Korg Trident]] series,<ref>{{Cite web|title=Korg Trident Service Manual|url=http://www.synthfool.com/docs/Korg/Korg_Trident_Service_manual/ |page=4 |publisher=Korg |via=Synthfool |access-date=10 February 2018}}</ref> and the [[Korg Poly-61]],<ref>{{cite web|title=Korg Poly-61 Service Manual|url=http://fa.utfs.org/diy/korgpoly61/Korg_Poly-61_ServiceManual.pdf|access-date=2013-03-07|archive-date=2010-06-02|archive-url=https://web.archive.org/web/20100602041214/http://fa.utfs.org/diy/korgpoly61/Korg_Poly-61_ServiceManual.pdf|url-status=dead}}</ref> [[Roland Jupiter-4]] and [[Roland ProMars]]<ref name="SOS11-04">{{cite web|title=The History Of Roland, Part 1: 1930–1978|url=http://www.soundonsound.com/sos/nov04/articles/roland.htm|work=The History Of Roland|publisher=Sound On Sound Magazine|access-date=29 November 2010|author=Gordon Reid|date=November 2004}}</ref> [[analog synthesizer]]s. The [[Sinclair QL]] used the closely related Intel 8049 to manage its keyboard, joystick ports, RS-232 inputs and audio. The ROM-less 8035 variant was used in [[Nintendo]]'s arcade game ''[[Donkey Kong (arcade game)|Donkey Kong]]'' to generate the background music.