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4-bit architecture
Revision as of 13:05, 16 January 2016 by 76.198.36.54 (talk) (I've reordered the industry section to put the first microprocessor first (this makes more sense chronologically), and also added some details about the intel 4004, 4040. I left off their address space b/c the intel 4004/4040 are different (12 bit/13 bit))

Architecture word sizes
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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 4-8-bit wide addresses.

Industry

Most of the first microprocessors during the early 1970s had 4-bit word length. The world's first single-chip microprocessor by Texas Instruments, the TMS1000, was a 4-bit CPU. Both the Intel 4004, the first commercial microprocessor, and the 4040 had a 4-bit word length, but had 8-bit instructions. 4-bit word were proven to be very limiting and by 1974 there was a shift to larger architectures such as 8-, 12- architectures. Some 4-bit chips are still made to date such as the Epson S1C63 MCU.

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. Today, 4-bit chips such as S1C63 are still manufactured are used in many low-power devices and wireless tools.

4-bit microprocessors

4-bit microcontrollers