8-bit 45148 222503442 2008-06-29T18:10:00Z Balmung0731 3091195 +ja {{dablink|This article is about 8-bit in computer architecture. For the era of computer gaming commonly referred to as "8-bit", see [[History of video game consoles (third generation)]]. For music in the 8-bit style, see [[8-bit (music)]]. For the sprite comic, see [[8-Bit Theater]]}} {{N-bit|8|(1 octet)}} 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 [[KB]]s. 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 [[smart card]]s{{Fact|date=January 2008}} and 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 computer]]s and [[game console]]s of the 70s and 80s. Many 8-bit CPUs or [[microcontroller]]s are the basis of today's ubiquitous [[embedded systems]]. There are 2<sup>8</sup> (256) possible values for 8 bits.(in binary) About 55% of all CPUs sold in the world are 8-bit microcontrollers or [[microprocessor]]s. {{Fact|date=April 2007}} ==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. Performance and memory limitations meant that 4-bit processors fell out of more demanding applications quickly (4-bit processors are still [[mass-produced]] however). ==List of 8-bit CPUs== A [[CPU]] can be classified on the basis of the [[data]] it can access in a single [[Instruction (computer science)|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. ''Examples of 8-bit processors (very incomplete):'' * [[Intel 8008]] * [[Intel 8080]] (''8008 source compatible'') * [[Intel 8085]] (''8080 binary compatible'') * [[Intel 8051]] (''Harward architecture'') * [[Zilog Z80]] (''8080 binary compatible'') * [[Zilog Z180]] (''Z80 binary compatible'') * [[Zilog Z8]] * [[Zilog eZ80]] (''Z80 binary compatible'') * [[Motorola 6800]] * [[Motorola 6809]] (''partially 6800 compatible'') * [[MOS Technology 6502]] * [[Microchip PIC10]][http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2060] * [[Microchip PIC12]][http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2553&param=en027589] * [[Microchip PIC16]][http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2553&param=en027586] * [[Microchip PIC18]][http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2042&param=en020453],[http://en.wikipedia.org/wiki/PIC_microcontroller] * [[Atmel AVR]] family microcontrollers [[de:8-Bit-Architektur]] [[es:8 bits]] [[eo:8-bita arkitekturo]] [[ko:8비트 컴퓨터]] [[it:8 bit]] [[ja:8ビット]] [[pl:Architektura 8-bitowa]] [[pt:8 bit]] [[sv:8-bitars CPU]] [[zh:8位元]]