Semiconductor & Computer Engineering
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 microprocessors during the early 1970s had 4-bit word sizes. Both the Intel 4004, the first commercial microprocessor, and the 4040 had a 4-bit word length, but had 8-bit instructions. Some of the first microcontrollers such as the TMS1000 made by Texas Instruments and NEC's 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 8- and 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 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 S1C60 and S1C63 MCU 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 microprocessors 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 BDC numbers representation.
Today, 4-bit chips such as S1C60 family are still manufactured are used in many low-power devices, wireless tools, and internet of things. Until recently Atmel's MARC4 was also a large player in the low-power RF/IR wireless market.
4-bit microprocessors
- AMD Am2900
- AMI 9209
- Fairchild 4700
- Fairchild 9400
- Fairchild PPS-25
- HP Saturn (64-bit register, 4-bit data path)
- Intel 4004 (HD35404)
- Intel 4040
- Motorola 10800
- National IMP-4
- Rockwell PPS-4
4-bit microcontrollers
- Atmel MARC4
- AMI S2000
- Epson S1C60
- Epson S1C63
- Fujitsu MB88200
- Fujitsu MB8840/400
- Fujitsu MB8850/500
- Hitachi HD404720
- Hitachi HMCS40
- Hitachi HMCS400
- ITT 7150
- Matsushita MN1400
- Matsushita MN1500
- Matsushita MN1700
- Mitsubishi MELPS 4
- Mitsubishi M50430/440
- Mitsubishi M50460/560
- Mitsubishi M5072/M5076
- Mitsubishi M5090
- MMI 5700
- National MAPS
- National COPS I
- National COPS II
- NEC 17K
- NEC μCOM-4
- NEC μPD751
- NEC μPD707
- NEC μPD7500
- NEC μPD75000
- OKI OLMS-40/50/60/64/65
- OKI OLMS-63K
- OKI OLMS-64K
- Rockwell PPS-4/1
- Sanyo LC65
- Sanyo 66xx
- Sanyo LM64xx
- Sharp SM
- Sony SPC500
- TI TMS1000
- Toshiba T3400
- Toshiba TLCS-42
- Toshiba TLCS-43
- Toshiba TLCS-46A
- Toshiba TLCS-47
- Toshiba TLCS-470
- WD CR1872
- WD WD4200
- Bell Labs BELLMAC-4