The 4-bit architecture is a microprocessor 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 8-bit wide addresses.
Industry
Most of the first microprocessors during the early 1970s had 4-bit word length. Both the Intel4004 and the 4040 were 4-bits. The world's first single-chip microprocessor by Texas Instruments, the TMS1000, was also a 4-bit CPU. 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 architecture architectures.
Applications
Most 4-bit microprocessors were used almost exclusively in calculators and toys. 4 bits was a logical choice for many calculators that used BDC numbers representation.
4-bit microprocessor
- AMD Am2900
- AMI 9209
- Fairchild 4700
- Fairchild 9400
- Fairchild PPS-25
- Hitachi HD35404
- HP Saturn (64-bit register, 4-bit data path)
- Intel 4004
- Intel 4040
- MMI 5700
- National IMP-4
- Rockwell PPS-4/1
- Rockwell PPS-4/2
- TMS1000
- Toshiba T3472
4-bit microcontrollers
- AMI S2000
- Epson S1C63
- Fujitsu MB8840
- Fujitsu MB8850/500
- Hitachi HD404729S
- Hitachi HMCS40
- ITT 7150
- National COPS I
- National COPS II
- National MM5799
- National MM57140
- National MM57152
- NEC μCOM-4
- NEC μPD751
- NEC μPD707
- Matsushita MN1400
- Matsushita MN1500
- Mitsubishi MELPS 4
- MARC4
- OKI MSM6411
- Sanyo LM6402G
- Sanyo LC587004
- Sanyo LC587008
- Sanyo LC58E68
- Sharp SM552
- Toshiba TLCS-47
- WD CR1872