Zilog Z80

Z80Z80AZ-80Zilog Z80AZilog Z-80NEC D780CµPD780780CD780C-1LH-0080
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product.wikipedia
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Zilog

Curtis J. CrawfordCurtis CrawfordZilog Incorporated
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product.
Its most famous product is the Z80 series of 8-bit microprocessors that were compatible with the Intel 8080 but significantly cheaper.

8-bit

8-bit computereight-bit8
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product.
The Zilog Z80 (compatible with the 8080) and the Motorola 6800 were also used in similar computers.

Intel 8080

8080i80808080A
The Zilog Z80 was a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems. Note that the assembled code is binary-compatible with the Intel 8080 and 8085 CPUs. He also developed the basic design methodology used for memories and microprocessors at Intel and led the work on the Intel 4004, the 8080 and several other ICs.
It became the engine of the Altair 8800, and subsequent S-100 bus personal computers, until it was replaced by the Z80 in this role, and was the original target CPU for CP/M operating systems developed by Gary Kildall.

Federico Faggin

Faggin, Federico
The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975.
He was co-founder (with Ralph Ungermann) and CEO of Zilog, the first company solely dedicated to microprocessors, and led the development of the Zilog Z80 and Z8 processors.

Home computer

home computershomehome computing
Although used in that role, the Z80 also became one of the most widely used CPUs in desktop computers and home computers from the 1970s to the mid-1980s.
Things were different in the business world, where cost-conscious small business owners had been using CP/M running on Z80 based computers from Osborne, Kaypro, Morrow Designs and a host of other manufacturers.

Zilog eZ80

eZ80
In recent decades Zilog has refocused on the ever-growing market for embedded systems and the most recent Z80-compatible microcontroller family, the fully pipelined 24-bit eZ80 with a linear 16 MB address range, has been successfully introduced alongside the simpler Z80 and Z180 products.
The Zilog eZ80 is an 8-bit microprocessor from Zilog which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.

Microprocessor

microprocessorsprocessorprocessors
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product.
The Zilog Z80 (1976) was also a Faggin design, using low voltage N channel with depletion load and derivative Intel 8-bit processors: all designed with the methodology Faggin created for the 4004.

Depletion-load NMOS logic

HMOSdepletion-modedepletion
These companies were chosen because they could do the ion implantation needed to create the depletion-mode MOSFETs that the Z80 design used as load transistors in order to cope with a single 5 Volt power supply.
Some depletion-load nMOS designs are still produced, typically in parallel with newer CMOS counterparts; one example of this is the Z84015 and Z84C15.

Zilog Z180

Z180
In recent decades Zilog has refocused on the ever-growing market for embedded systems and the most recent Z80-compatible microcontroller family, the fully pipelined 24-bit eZ80 with a linear 16 MB address range, has been successfully introduced alongside the simpler Z80 and Z180 products.
The Zilog Z180 eight-bit processor is a successor of the Z80 CPU.

CP/M

CP/M-80CP/M operating systemBDOS
Faggin designed the instruction set to be binary compatible with the Intel 8080 so that most 8080 code, notably the CP/M operating system and Intel's PL/M compiler for 8080 (as well as its generated code), would run unmodified on the new Z80 CPU.
The code for ZCPR3 could also be compiled (with reduced features) for the 8080 and would run on systems that did not have the requisite Z80 microprocessor.

Intel 8085

8085Intel 827580C85
Note that the assembled code is binary-compatible with the Intel 8080 and 8085 CPUs.
This capability matched that of the competing Z80, a popular 8080-derived CPU introduced the year before.

Computer

computerscomputer systemdigital computer
It was also common in military applications, musical equipment, such as synthesizers, and in the computerized coin operated video games of the late 1970s and early 1980, the arcade machines or video game arcade cabinets.

Intel 4004

4004MCS-4first commercially available microprocessor (Intel 4004)
He also developed the basic design methodology used for memories and microprocessors at Intel and led the work on the Intel 4004, the 8080 and several other ICs.
His methodology set the design style for all the early Intel microprocessors and later for the Zilog Z80.

Masatoshi Shima

Shima Masatoshi
Masatoshi Shima, the principal logic and transistor level-designer of the 4004 and the 8080 under Faggin's supervision, joined the Zilog team.
He then joined Zilog, where he worked with Faggin to develop the Zilog Z80 (1976) and Z8000 (1979).

24-bit

24 bits24 bit24 bits per pixel
In recent decades Zilog has refocused on the ever-growing market for embedded systems and the most recent Z80-compatible microcontroller family, the fully pipelined 24-bit eZ80 with a linear 16 MB address range, has been successfully introduced alongside the simpler Z80 and Z180 products.
The eZ80 is a microprocessor and microcontroller family, with 24-bit registers and therefore 24-bit linear addressing, that is binary compatible with the 8/16-bit Z80.

ZX81

Sinclair ZX81ZX-81Sinclair ZX-81
It has also been employed as a "hardware" counter in some designs; an example of this is the ZX81, which lets it keep track of character positions on the TV screen by triggering an interrupt at wrap around (by connecting INT to A6). This feature has also been used to minimise decoding hardware requirements, such as in the Amstrad CPC/PCW and ZX81. The µPD780C was used in Sinclair's ZX80, ZX81 and early versions of the ZX Spectrum, in several MSX computers, and in musical synthesizers such as Oberheim OB-8 and others, while the µPD780-1 (a Z80A part which ran at 4 MHz) was used in Sega's SG-1000 game console.
There are only three other onboard chips: a 3.5 MHz Z80A 8-bit microprocessor from NEC, an uncommitted logic array (ULA) chip from Ferranti, and an 8 KB ROM providing a simple BASIC interpreter.

Mostek

Mostek Corporation
Zilog licensed the Z80 to the US-based Synertek and Mostek, which had helped them with initial production, as well as to a European second source manufacturer, SGS.
Mostek produced MK3880, the Zilog Z80 and a series of Z80 support chips, until Zilog built their own fab.

Intel 8086

808680C86Intel-8086
Apart from naming differences, and despite a certain discrepancy in basic register structure, the Z80 and 8086 syntax are virtually isomorphic for a large portion of instructions.
Other well known 8-bit microprocessors that emerged during these years are Motorola 6800 (1974), General Instrument PIC16X (1975), MOS Technology 6502 (1975), Zilog Z80 (1976), and Motorola 6809 (1978).

Backward compatibility

backward compatiblebackward-compatiblebackwards compatible
The Zilog Z80 was a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems.
The Zilog Z80, however, was fully backwards compatible with the Intel 8080.)

Amstrad CPC

CPCAmstradAmstrad CPC 6128
This feature has also been used to minimise decoding hardware requirements, such as in the Amstrad CPC/PCW and ZX81.
The CPC models' hardware is based on the Zilog Z80A CPU, complemented with either 64 or 128 KB of RAM.

Illegal opcode

illegal instructioninvalid opcodeundocumented instructions
Undocumented or illegal opcodes are not detected by the Z80 and have various effects, some of which are useful.
Illegal opcodes were common on older CPUs designed during the 1970s, such as the MOS Technology 6502, Intel 8086, and the Zilog Z80.

ZX Spectrum

Sinclair ZX SpectrumWorld of SpectrumSinclair Spectrum
The µPD780C was used in Sinclair's ZX80, ZX81 and early versions of the ZX Spectrum, in several MSX computers, and in musical synthesizers such as Oberheim OB-8 and others, while the µPD780-1 (a Z80A part which ran at 4 MHz) was used in Sega's SG-1000 game console.
The Spectrum is based on a Zilog Z80 A CPU running at 3.5 MHz (or NEC D780C-1 clone).

Sharp MZ

Sharp MZ-2000Sharp MZ-700Sharp MZ-80K
The LH0080 was used in various home computers and personal computers made by Sharp and other Japanese manufacturers, including Sony MSX computers, and a number of computers in the Sharp MZ series.
Although commonly believed to stand for "Microcomputer Z80", the term MZ actually has its roots in the MZ-40K, a home computer kit produced by Sharp in 1978 which was based on Fujitsu's 4-bit MB8843 processor and provided a simple hexadecimal keypad for input.

Integrated circuit

integrated circuitsmicrochipchip
With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years.

Self-modifying code

self-modifyingrun-time code generationRuntime Code Generation
It was not uncommon for programmers to "poke" different (typically calculated dynamically) offset displacement bytes into indexed instructions; this is an example of self-modifying code which was regular practice on nearly all early 8-bit processors with non-pipelined execution units.
Below is an example in Zilog Z80 assembly language.