![]() As a sound coprocessor in many, many arcade game systems, including many of Sega's 1985-1993 boards.Sega's SG-1000 uses the NEC 780C, a binary-compatible clone of the Z80. ![]() Both the SNK Neo Geo and Sega Mega Drive video games consoles use it as an audio coprocessor.Neo Geo Pocket and Neo Geo Pocket Color.A number of Sega arcade systems used the Z80 as the CPU, starting with the Sega VIC Dual in 1977.Competitor MOS Technology, Inc, maker of the famous 6502 processor, later included this very useful feature in its second generation color video chip VIC-II. Perhaps key to the success of the Z80 was the built-in DRAM controller and memory refresh register (R), which allowed systems to be built with fewer support chips. Later versions increased in speed from the early models' 1 MHz up to as much as 20 MHz. The Z80 quickly took over from the 8080 in the market, and became the most popular 8-bit CPU of all time - indeed, if one takes the absolute size of the market into account, the most successful CPU ever. a built-in DRAM refresh address counter that would otherwise have to be provided by external circuitry.a limited ability for SIMD (Single Instruction, Multiple Data) with instructions to perform copy, compare, input, and output over contiguous blocks of memory.two instances of each of the 16-bit registers AF (accumulator+flags), BC, DE, and HL, which could be quickly switched between to speed up response to interrupts or other context-switching.an enhanced instruction set including the new indexing registers IX/IY and instructions for them, many new bit-manipulating and shifting operations, and enhanced capabilities for processing interrupts. ![]() The Z80 offered five real improvements over the 8080: Masatoshi Shima, the principal logic and transistor level-designer of the Intel 4004 and the 8080, designed most of the microarchitecture as well as the gate and transistor levels of the Z80. ![]() It was designed to be binary compatible with the Intel 8080 so that code for the latter could run unmodified on it, notably the CP/M operating system. By July 1976, Zilog had the Z80 on the market. The Z80 was set in motion at the end of 1974, when Federico Faggin left Intel, after working on the 8080, to found Zilog with Ralph Ungermann. The Z80 is an enhanced (and fully binary-compatible) version of the Intel 8080. ![]()
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