Intel 8080

The Intel 8080 is an 8-bit microprocessor produced by Intel, first released in April 1974. It served as the successor to the 8008, despite not being binary compatible with it. Originally intended for use in embedded systems such as calculators, cash registers, computer terminals, and industrial robots, the 8080 became a popular processor used across a wide range of devices, and contributed to the rise of the microcomputer industry. Several key design choices contributed to the 8080’s success. Its 40‑pin package simplified interfacing compared to the 8008’s 18‑pin design, enabling a more efficient data bus. The transition to NMOS technology provided faster transistor speeds than the 8008's PMOS, also making it TTL compatible. An expanded instruction set and a full 16-bit address bus allowed the 8080 to access up to 64 KB of memory, quadrupling the capacity of its predecessor. A broader selection of support chips further enhanced its functionality. Many of these improvements stemmed from customer feedback, as designer Federico Faggin and others at Intel heard from industry about shortcomings in the 8008 architecture. The 8080 found its way into early personal computers such as the Altair 8800 and subsequent S-100 bus systems, and it served as the original target CPU for the CP/M operating system. It directly influenced the later x86 architecture, which was designed so that its assembly language closely resembled that of the 8080, permitting many instructions to map directly from one to the other. Originally operating at a clock rate of 2 MHz, with common instructions taking between 4 and 11 clock cycles, the 8080 was capable of executing several hundred thousand instructions per second. Later, two faster variants, the 8080A-1 and 8080A-2, offered improved clock speeds of 3.125 MHz and 2.63 MHz, respectively. In most applications, the processor was paired with two support chips,...