8-BIT

Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their address space is limited to 64 kibibytes. This is not a "natural law", however, so there are exceptions.
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 (compatible with the 8080) and the Motorola 6800 were also used in similar computers. The Z80 and the MOS Technology 6502 8-bit CPUs were widely used in home computers and game consoles of the 70s and 80s. Many 8-bit CPUs or microcontrollers are the basis of today's ubiquitous embedded systems.
There are 2⁸ (256) possible permutations for 8 bits.(in binary)
About 55% of all CPUs sold in the world are 8-bit microcontrollers or microprocessors.

Contents

Why 8 bits?

List of 8-bit CPUs

8-bit Intel CPUs

List of competitor compatible CPUs to Intel 8-bit architecture

8-bit Motorola CPUs

List of competitor CPUs similar to Motorola 8-bit architecture

Why 8 bits?

4-bit microprocessors were developed in the early 1970s starting with the Intel 4004. Intel swiftly followed with 8-bit processors, and most competitors to Intel started with 8-bits. This, combined with the performance and memory limitations of the available 4-bit processors, meant that they fell out of commercial application quickly.

List of 8-bit CPUs

A CPU can be classified on the basis of the data it can access in a single operation. An 8-bit processor can access 8 bits of data in a single operation, as opposed to a 16-bit processor, which can access 16 bits of data in a single operation.

8-bit Intel CPUs

★ Intel 8008

★ Intel 8051

★ Intel 8080

★ Intel 8085

★ Intel 8088
^★ NOTE: Intel 8088 is 8-bit externally only

★ Intel 80188
^★ NOTE: Intel 8088 is 8-bit externally only

List of competitor compatible CPUs to Intel 8-bit architecture

★ Zilog Z80

★ Zilog Z800

8-bit Motorola CPUs

: ''see main article: 68h''

★ Motorola 6800

List of competitor CPUs similar to Motorola 8-bit architecture

★ MOS Technology 6501

★ MOS Technology 6502

★ MOS Technology 6510