Intel 8080

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Intel 8080A processor
Production:	1974 to 1990s
Producers: Intel AMD NEC Siemens AG
Processor clock:	2 MHz to 3.125 MHz
Manufacturing :	6 µm, NMOS
Instruction set :	Intel 8 bit
Base:	40-pin DIP

The Intel 8080 is a 1974 introduced 8-bit - microprocessor in NMOS technology from Intel . It is widely regarded as the first full-fledged microprocessor. It was the successor to the Intel 8008 and was source code compatible with its instruction set, but not binary compatible, so programs had to be reassembled .

Architecture and use

Intel 8080 : Function Block Diagram

The 40-pin design enabled a 16-bit address bus so that the 8080 could address 64 KB of memory. In addition, 256 input / output registers independent of the address area could be connected.

It had seven 8-bit registers, six of which could be combined into three 16-bit registers, as well as a stack pointer and a program pointer with 16 bits each. The CP / M operating system was developed for the 8080 and was the predominant system for microcomputers for nearly a decade , much like MS-DOS later .

The 8080 was used in control units (e.g. for cruise missiles ) and the first personal computers (including IMSAI and Altair 8800 ).

In addition to the processor, a system with the 8080 also required two further components: a separate clock generator ( 8224 ) and a bus controller ( 8228 ). In 1976 the successor 8085 appeared , which already contained their functions. However, it was not very successful, as in the same year Zilog brought out an 8080-compatible, but greatly expanded processor with the Z80 . At the end of the 1970s, the KR580VM80A, compatible with the 8080, appeared in the Soviet Union . and in the early 1980s the MHB8080A appeared in Czechoslovakia .

Technical specifications

• Supply voltages: +12 V, +5 V, −5 V
• Max. Clock frequency: 2 MHz
• Number of transistors: 6000 at 6 µm
• Data bus: 8 bit
• Address bus: 16 bit
• Addressable memory: 64 KB
• Addressable I / O area: 256 B

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  Clone NEC 8080AF

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  Clone AMD Am9080 (manufactured 1977)

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  Intel 8080A in a ceramic case

Peripheral modules

• Intel 8251 serial interface
• Intel 8253 counter / timer
• Intel 8255 parallel interface
• Intel 8257 DMA controller
• Intel 8259 interrupt control

Web links

Commons : Intel 8080  - collection of pictures, videos and audio files

• Intel 8080 - Collectors website with lots of pictures
• Patent US4010449 : MOS computer employing a plurality of separate chips. Published March 1, 1977 , Inventors: Federico Faggin, Masatoshi Shima, Stanley Mazor. ‌
• Online emulator

Individual evidence

1. ↑ zeptobars.com