4-bit

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In computer architecture, 4-bit integers, memory addresses, or other data units are those that are at most 4 bits wide. Also, 4-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. The Intel 4004, the world's first commercially available single-chip microprocessor, was a 4-bit CPU. The F-14 Tomcat's Central Air Data Computer (or F14 CADC) was created a year before the 4004, but its existence was classified by the United States Navy until 1997. Also, the HP48 Saturn processor (a commonly used scientific calculator) is basically a 4-bit machine, though it strings multiple words together, e.g. its 20-bit memory addressing.

The 1970s saw the emergence of 4-bit software applications for mass markets like pocket calculators.

With 4 bits, it is possible to create 16 different values. All single digit hexadecimal numbers can be written with 4 bits.

[edit] List of 4-bit Processors

This section requires expansion.

• Intel 4004
• Intel 4040
• Atmel MARC4 core (atmel.com) - Mature. Not recommended for new designs.
• Toshiba TLCS-47 series
• HP Saturn (microprocessor)
• NEC μPD75X
• NEC μPD6P9 infrared remote control transmitter microcontroller[1]

[edit] External references

• Saturn CPU link

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