- published: 01 Mar 2015
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The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility. The initial specified clock frequency limit was 2 MHz and with common instructions having execution times of 4, 5, 7, 10 or 11 cycles this meant a few hundred thousand instructions per second. The 8080 has sometimes been labeled "the first truly usable microprocessor", although earlier microprocessors were used for calculators and other applications.
The 8080 was implemented using non-saturated enhancement-load NMOS, demanding an extra +12 volt and a −5 volt supply.
The Intel 8080 was the successor to the 8008. It used the same basic instruction set as the 8008 (developed by Computer Terminal Corporation) and was source code compatible with its predecessor, but added some handy 16-bit operations to the instruction set as well. The 8080's large 40-pin DIP packaging permitted it to provide a 16-bit address bus and an 8-bit data bus, allowing easy access to 64 kilobytes of memory.