Editing 4-bit architecture

{{Architecture sizes}}
The '''4-bit [[architecture]]''' is a [[microprocessor]] or [[computer]] architecture that has a [[datapath]] width or a highest [[operand]] width of 4 bits or a [[nibble]]. These architectures typically have a matching [[register file]] with [[registers]] width of 4 bits and 4-8-bit wide addresses.

== Industry ==
Most of the first [[microprocessor]]s during the early 1970s had 4-bit [[word]] sizes. Both the Intel {{intel|4004}}, the first commercial microprocessor, and the {{intel|4040}} had a 4-bit word length, but had {{arch|8}} instructions. Some of the first [[microcontroller]]s such as the {{ti|TMS1000}} made by [[Texas Instruments]] and NEC's {{nec|μPD751}} also had 4-bit words. 4-bit word were proven to be very limiting and by 1974 there was a shift to larger architectures such as {{arch|8|8-}} and {{arch|12|12-}} bit architectures.

In the [[microcontroller]] domain, the story is a little different. 4-bit microcontrollers found their way into many battery-powered and low power instruments and devices.  Some 4-bit chips such as the {{atmel|MARC4|Atmel MARC4}} continued to be manufactured until very recently (2010s), those devices aimed directly at wireless devices such as RFID-related applications. Other 4-bit MCUs are still made to date such as the [[Epson]]'s {{epson|S1C60}} and {{epson|S1C63}} MCU [[microprocessor family|families]]. Modern 4-bit microprocessors, however, are much different from the first generation microprocessors of the 1970s - in terms of architecture, performance, and overall capabilities.

== Applications ==
Most of the early 4-bit [[microprocessor]]s were used almost exclusively in calculators and toys, later on for various utilities, video games, controllers, and early computers. 4 bits was a logical choice for many calculators that used [[binary coded decimal|BDC]] numbers representation.

Today, 4-bit chips such as {{epson|S1C60|S1C60 family}} are still manufactured are used in many low-power devices, wireless tools, and [[internet of things]]. Until recently Atmel's {{atmel|MARC4}} was also a large player in the low-power RF/IR wireless market.

== 4-bit microprocessors ==
* {{amd|Am2900|AMD Am2900}}
* {{ami|9209|AMI 9209}}
* {{fairchild|4700|Fairchild 4700}}
* {{fairchild|9400|Fairchild 9400}}
* {{fairchild|PPS-25|Fairchild PPS-25}}
* {{hitachi|hmcs-4/hd35404|Hitachi HD35404}}
* [[HP Saturn]] (64-bit register, 4-bit data path)
* {{intel|4004|Intel 4004}}
* {{intel|4040|Intel 4040}}
* {{motorola|10800|Motorola 10800}}
* {{national|IMP-4|National IMP-4}}
* {{rockwell|PPS-4|Rockwell PPS-4}}

== 4-bit microcontrollers ==
* {{atmel|MARC4|Atmel MARC4}}
* {{ami|S2000|AMI S2000}}
* {{epson|S1C60|Epson S1C60}}
* {{epson|S1C63|Epson S1C63}}
* {{fujitsu|MB88200|Fujitsu MB88200}}
* {{fujitsu|MB8840|Fujitsu MB8840}}/{{fujitsu|MB88400|400}}
* {{fujitsu|MB8850|Fujitsu MB8850}}/{{fujitsu|MB88500|500}}
* {{hitachi|HD404720|Hitachi HD404720}}
* {{hitachi|HMCS40|Hitachi HMCS40}}
* {{hitachi|HMCS400|Hitachi HMCS400}}
* {{itt|7150|ITT 7150}}
* {{national|MAPS|National MAPS}}
* {{national|COPS I|National COPS I}}
* {{national|COPS II|National COPS II}}
* {{nec|17K|NEC 17K}}
* {{nec|μCOM-4|NEC μCOM-4}}
* {{nec|μPD751|NEC μPD751}}
* {{nec|μPD707|NEC μPD707}}
* {{matsushita|MN1400|Matsushita MN1400}}
* {{matsushita|MN1500|Matsushita MN1500}}
* {{mitsu|MELPS 4|Mitsubishi MELPS 4}}
* {{mmi|5700|MMI 5700}}
* {{oki|OLMS-40|OKI OLMS-40}}
* {{oki|OLMS-50|OKI OLMS-50}}
* {{oki|OLMS-60|OKI OLMS-60}}
* {{oki|OLMS-64|OKI OLMS-64}}
* {{oki|OLMS-65|OKI OLMS-65}}
* {{oki|OLMS-63K|OKI OLMS-63K}}
* {{oki|OLMS-64K|OKI OLMS-64K}}
* {{rockwell|PPS-4-1|Rockwell PPS-4/1}}
* [[Sanyo LM6402G]]
* [[Sanyo LC587004]]
* [[Sanyo LC587008]]
* [[Sanyo LC58E68]]
* {{sharp|SM|Sharp SM}}
* {{ti|TMS1000|TI TMS1000}}
* {{toshiba|T3400|Toshiba T3400}}
* [[Toshiba TLCS-47]]
* {{wd|CR1872 series|WD CR1872}}
* {{wd|WD4200|WD WD4200}}

[[Category:4-bit microprocessors]]