Zilog introduced the Z80 microprocessor in March 1976 after a development effort that began in 1975 and was funded by Exxon Enterprises. The project was led by Federico Faggin, Ralph Ungermann and Masatoshi Shima, who designed the chip to be a 5‑V, 8‑bit processor compatible with Intel’s 8080 and to add functions from the Motorola 6800. Using 8,200 transistors, the Z80 offered an 8‑bit data bus, a 16‑bit address bus, support for 78 instructions compatible with the 8080, 20 eight‑bit registers, four sixteen‑bit registers and a memory address space of up to 64 KB. The first working prototype was demonstrated on March 9, 1976 by an 11‑member team, and development cost was reported to be under $400,000. The Z80 was adopted by home computer manufacturers such as Radio Shack (TRS‑80), SORD, Sinclair (ZX81, ZX Spectrum), Kaypro and found use in industrial embedded systems. Its popularity declined after Intel introduced 16‑bit processors in the mid‑1980s, but enhanced versions such as the ez80 remain in use in Texas Instruments calculators and other devices. Zilog continues to produce Z80‑based microprocessors and intelligent peripheral controllers, which are available from major electronics component distributors. The Z80 is regarded as one of the longest‑living microprocessor families in the industry.