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One of the first Z80 microprocessors manufactured; the date stamp is from June 1976.
One of the first Z80 microprocessors manufactured; the date stamp is from June 1976.
A CMOS Z80 in a QFP package.
A CMOS Z80 in a QFP package. Complementary metal–oxide–semiconductor ( CMOS) (pronounced "see-moss" siːmɔːs ˈsiːmɒs is a major class of Integrated circuits CMOS technology A QFP or Quad Flat Package is an Integrated circuit package with leads extending from each of the four sides

The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their Address space is limited to 64 KBs This is not a "natural A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated Zilog Inc, often seen as ZiLOG (the official company denotation in 1998 through Jun 2007 is a manufacturer of 8-bit, 16-bit, 24-bit Year 1976 ( MCMLXXVI) was a Leap year starting on Thursday (link will display full calendar of the Gregorian calendar. It was widely used both in desktop and embedded computer designs as well as for military purposes. An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints The Z80 and its derivatives and clones make up one of the most commonly used CPU families of all time, and, along with the MOS Technology 6502 family, dominated the 8-bit microcomputer market from the late 1970s to the mid-1980s. MOS Technology Inc, also known as CSG (Commodore Semiconductor Group, was a semiconductor design and fabrication company based in Norristown Pennsylvania The MOS Technology 6502 is an 8-bit Microprocessor that was designed by Chuck Peddle for MOS Technology in 1975

Although Zilog made early attempts with advanced mini-computer like versions of the Z80-architecture (Z800 and Z280), these chips never caught on. A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user The Zilog Z800 was a 16-bit Microprocessor designed by Zilog to be released in 1985. The Zilog Z280 was an enhancement of the Zilog Z80 architecture introduced in July 1987, basically a slighly improved CMOS version of the earlier NMOS The company was also trying hard in the workstation market with its Z8000 and 32-bit Z80000 (both unrelated to Z80). A workstation, such as a Unix workstation, RISC workstation or Engineering workstation, is a high-end Microcomputer The Z8000 was a 16-bit Microprocessor introduced by ZiLOG in 1979 The range of Integer values that can be stored in 32 bits is 0 through 4294967295 or −2147483648 through 2147483647 using Two's complement encoding The Z80000 was Zilog 's 32-bit processor from 1986, an expansion of its 16-bit predecessor the Zilog Z8000. In recent decades Zilog has refocused on the ever-growing market for embedded systems (for which the original Z80 and the Z180 were designed) 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 Z180 and Z80 products. An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints The Zilog Z180 8-bit processor is a successor of the Z80 CPU It is compatible with the large base of software written for the Z80 A microcontroller (also MCU or µC is a functional Computer system-on-a- chip. The IBM System/360, announced in 1964, was an extremely popular computer system with 24-bit addressing and 32-bit general registers and arithmetic The ZiLOG eZ80 is an 8-bit Microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor The word linear comes from the Latin word linearis, which means created by lines. The Zilog Z180 8-bit processor is a successor of the Z80 CPU It is compatible with the large base of software written for the Z80

Zilog licensed the Z80 core to any company wishing to make the device royalty free, though many East European and Russian manufacturers made unlicensed copies. In Electronic design a Semiconductor intellectual property core, IP block, IP core, or logic core is a reusable unit of logic cell Royalty Free refers to a type of contract between a two entities (the licensor and licensee that is employed when licensing the rights to use content such as photographs This enabled a small company's product to gain acceptance in the world market since second sources from far larger companies such as Toshiba started to manufacture the device. In the Electronics industry a second source is a company that is licensed to manufacture and sell components originally designed by another company (the first source ( is a multinational conglomerate manufacturing company headquartered in Tokyo, Japan. Consequently Zilog has made less than 50% of the Z80s since its conception.

Contents

Brief history and overview

The Z80 came about when Federico Faggin, after working on the 8080, left Intel at the end of 1974 to found Zilog with Ralph Ungermann, and by July 1976 they had the Z80 on the market. Federico Faggin (born December 1 1941) is an Italian -born Physicist / Electrical engineer, principally responsible for the design of The Intel 8080 was an early Microprocessor designed and manufactured by Intel. It was designed to be binary compatible with the Intel 8080 so that most 8080 code, notably the CP/M operating system, would run unmodified on it. The Intel 8080 was an early Microprocessor designed and manufactured by Intel. CP/M (Control Program for Microcomputers is an Operating system originally created for Intel 8080 / 85 based Microcomputers by Gary Kildall

The Z80's original DIL40 chip package pinout.
The Z80's original DIL40 chip package pinout. In Microelectronics, a dual in-line package (DIP, sometimes called a DIL package is an electronic device package with a rectangular housing and two parallel rows

The Z80 offered many real improvements over the 8080:

The Z80 quickly took over from the 8080 in the market, and became one of the most popular 8-bit CPUs. An instruction set is a list of all the instructions and all their variations that a processor can execute An index register in a computer's CPU is a Processor register used for modifying Operand addresses during the run of a program typically for doing vector/ An interrupt vector is the Memory address of an Interrupt handler, or an index into an array called an Interrupt vector table or dispatch table A register file is an array of Processor registers in a central processing unit (CPU. In Computing, an interrupt is an asynchronous signal from hardware indicating the need for attention or a synchronous event in software indicating the need for a change Memory refresh is the process of periodically reading information from an area of Computer memory, and immediately rewriting the read information to the same area with no modifications Perhaps a key to the success of the Z80 was the built-in DRAM refresh, and other features which allowed systems to be built with fewer support chips.

The specified maximum clock frequency increased successively from the introductory 2. 5 MHz, via the "standard" 4 MHz, up to 6 and 8 MHz, for the original NMOS design. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. A CMOS version was also developed with a specified maximum clock frequency[1] ranging from 4 MHz up to 20 MHz (for the version sold today). Complementary metal–oxide–semiconductor ( CMOS) (pronounced "see-moss" siːmɔːs ˈsiːmɒs is a major class of Integrated circuits CMOS technology The fully compatible derivatives Z180 and eZ80 are currently specified for up to 33 and 50 MHz respectively. The Zilog Z180 8-bit processor is a successor of the Z80 CPU It is compatible with the large base of software written for the Z80 The ZiLOG eZ80 is an 8-bit Microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor

Technical description

Programming model and register set

The programming model and register set are conventional and similar to many other processors, such as the related x86 family. See also X86 assembly language The generic term x86 refers to the most commercially successful Instruction set architecture in the history of Personal The 8080 compatible registers AF,BC,DE,HL are duplicated as two separate banks in the Z80, where the processor can quickly switch from one bank to the other; a feature useful for speeding up responses to single level, high priority interrupts. The Intel 8080 was an early Microprocessor designed and manufactured by Intel. This feature was present in the Datapoint 2200 but was not implemented by Intel in the 8008. Technical description The Datapoint 2200 had a built-in full-travel keyboard, a built-in 12-line 80-column green screen monitor and two cassette The dual-register set makes sense as the Z80 (like most microprocessors at the time) was really intended for embedded use, not for personal computers, or the yet-to-be invented home computers. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s [2] It also turned out to be quite useful for hard-optimized manual assembly coding. Some software, especially games for the ZX Spectrum took Z80 assembly optimization to rather extreme levels, employing the duplicated registers among other things. The Sinclair ZX Spectrum is an 8-bit personal Home computer released in the United Kingdom in 1982 by Sinclair Research Ltd

The Z80 architecture.
The Z80 architecture.

The 8080 compatible registers:

Registers introduced with the Z80:

There is no direct access to the alternate registers, instead two special instructions, EX AF,AF' and EXX, each toggles one of two multiplexer flipflops; this enables fast context switches for interrupt service routines: EX AF,AF' may be used alone (for really simple and fast interrupt routines) or together with EXX to swap the whole AF,BC,DE,HL set; still much faster than pushing the same registers on the stack (slower, lower priority, or multi level interrupts normally use the stack to store registers). In a Computer 's central processing unit ( CPU) an accumulator is a register in which intermediate arithmetic and logic results are stored In Computing and electronic systems binary-coded decimal ( BCD) is an encoding for decimal numbers in which each digit is represented by its own binary

The refresh register, R, increments[3] each time the CPU fetches an opcode (or opcode prefix) and has therefore no simple relationship with program execution. This has sometimes been used to generate pseudorandom numbers in games, and also in software protection schemes. A pseudorandom process is a process that appears random but is not It has also been employed as a "hardware" counter in some designs; a famous 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). The Sinclair ZX81 Home computer, released by Sinclair Research in 1981, was the follow up to the company's ZX80.

The interrupt vector register, I, is used for the Z80 specific mode 2 interrupts (selected by the im 2 instruction). It supplies the base address for a 128-entry table of service routine addresses which are selected via a pointer sent to the CPU during an interrupt acknowledge cycle. An interrupt handler, also known as an interrupt service routine ( ISR) is a callback subroutine in an Operating system or Device driver In Computing, an interrupt is an asynchronous signal from hardware indicating the need for attention or a synchronous event in software indicating the need for a change The pointer identifies a particular peripheral chip and/or peripheral function or event, where the chips are normally connected in a so called daisy-chain for priority resolution. Like the refresh register, this register has also sometimes been used creatively.

The Z80 assembly language

Background - the Datapoint 2200 and Intel 8008

The first Intel 8008 assembly language was based on a very simple (but systematic) syntax inherited from the Datapoint 2200 design. The Intel 8008 was an early byte-oriented Microprocessor designed and manufactured by Intel and introduced in April 1972 Technical description The Datapoint 2200 had a built-in full-travel keyboard, a built-in 12-line 80-column green screen monitor and two cassette This original syntax was later transformed into a new, somewhat more traditional, assembly language form for this same original 8008 chip. At about the same time, the new assembly language was also extended to accommodate the added addressing possibilities in the more advanced Intel 8080 chip (the 8008 and 8080 shared a language subset without being binary compatible; the 8008 actually was binary compatible with the Datapoint 2200 however). The Intel 8080 was an early Microprocessor designed and manufactured by Intel.

In this process, the mnemonic L, for LOAD, was replaced by various abbreviations of the words LOAD, STORE and MOVE, intermixed with other symbolic letters. The mnemonic letter M, for memory (referenced by HL), was lifted out from within the instruction mnemonic to become a syntactically freestanding operand, while registers and combinations of registers became very inconsistently denoted; either by abbreviated operands (MVI D, LXI H etc), within the instruction mnemonic itself (LDA, LHLD etc), or both at the same time (LDAX B, STAX D etc). 

Datapoint 2200
& i8008       i8080        Z80          i8086/i8088
(ca -1973)  (ca 1974)     (1976)          (1978)

LBC        MOV B,C      LD B,C           MOV BL,CL

--         LDAX B       LD A,(BC)        MOV AL,[BX]
LAM        MOV A,M      LD A,(HL)        MOV AL,[BP]
LBM        MOV B,M      LD B,(HL)        MOV BL,[BP]

--         STAX D       LD (DE),A        MOV [DX],AL
LMA        MOV M,A      LD (HL),A        MOV [BP],AL
LMC        MOV M,C      LD (HL),C        MOV [BP],CL

LDI 56     MVI D,56     LD D,56          MOV DL,56
LMI 56     MVI M,56     LD (HL),56       MOV byte ptr [BP],56

--         LDA 1234     LD A,(1234)      MOV AL,[1234]
--         STA 1234     LD (1234),A      MOV [1234],AL

--         --           LD B,(IX+56)     MOV BL,[SI+56]
--         --           LD (IX+56),C     MOV [SI+56],CL
--         --           LD (IY+56),78    MOV byte ptr [DI+56],78

--         LXI B,1234   LD BC,1234       MOV BX,1234
--         LXI H,1234   LD HL,1234       MOV BP,1234

--         SHLD 1234    LD (1234),HL     MOV [1234],BP
--         LHLD 1234    LD HL,(1234)     MOV BP,[1234]
--         --           LD BC,(1234)     MOV BX,[1234]
--         --           LD IX,(1234)     MOV SI,[1234]

Illustration of four syntaxes, using samples of equivalent, or (for 8086) very similar, load and store instructions.

The new syntax

According to Masatoshi Shima, certain people within Zilog wanted a "computer oriented" image for the company, and also felt they needed to "differentiate" their first product from the 8080. Masatoshi Shima (嶋正利 Shima Masatoshi, born on August 22[[ 943]] in Shizuoka, Japan) was one of the designers of the world's first Microprocessor Intel had also claimed copyright on their assembly mnemonics. Yet another assembly syntax was therefore developed, but this time with a more systematic approach:

These principles made it straightforward to find names and forms for all new Z80 instructions, as well as orthogonalizations of old ones, such as LD BC,(1234) above.

It is interesting to see the resemblance between Z80 and 8086 syntax, as illustrated by the table. The 8086 is a 16-bit Microprocessor chip designed by Intel and introduced on the market in 1978 which gave rise to the X86 architecture Apart from naming differences, and despite a certain discrepancy in basic register structure, the two are virtually isomorphous for a large portion of instructions. Whether this is due to some common influence on both design teams (above 8080, such as PDP-11), the competitive nature of the relation between the two designs, or maybe just a matter of taste, is, so far, uncertain. The Intel 8080 was an early Microprocessor designed and manufactured by Intel. The PDP-11 was a series of 16-bit Minicomputers sold by Digital Equipment Corp [4]

Instruction set and encoding

The Z80 uses 252 out of the available 256 codes as single byte opcodes; the four remaining codes are used extensively as opcode prefixes: CB and ED enable extra instructions and DD or FD selects IX+d or IY+d respectively (in some cases without displacement d) in place of HL. This scheme gives the Z80 a large number of permutations of instructions and registers; ZiLOG categorizes these into 158 different "instruction types", 78 of which are the same as those of the Intel 8080 (allowing operation of 8080 programs on a Z80). The ZiLOG documentation further groups instructions into the following categories:

The bit set, reset, and test instructions are well adapted to I/O control. No multiply instruction is available in the original Z80. Different sizes and variants of additions, shifts, and rotates have somewhat differing effects on flags because the flag-influencing properties of the 8080 had to be copied for compatibility. Load instructions do not affect the flags (except for the special purpose I and R register loads). The index register instructions are useful for reducing code size, and, while some of them are not much faster than "equivalent" sequences of simpler operations, they also save execution time indirectly by reducing the need to save and restore registers. [5] Similarly, instructions for 16-bit additions are not particularly fast (11 clocks) in the original Z80; nonetheless, they are about twice as fast as performing the same calculations using 8-bit operations, and equally important, they reduce register usage. [6]

Undocumented instructions

The index registers, IX and IY, were intended as flexible 16 bit pointers, enhancing the ability to manipulate memory, stack frames and data structures. Officially, they were treated as 16 bit only. In reality, they were implemented as a sort of copy of the HL register which is accessible as 16 bits or as a pair of 8 bit pair registers (H and L). Even the binary opcodes (machine language) were identical, but preceded by a new opcode prefix, as mentioned above. ZiLOG published the opcodes and related mnemonics for the intended functions, but did not document the fact that every opcode that allowed manipulation of the H and L registers was equally valid for the 8 bit portions of the IX and IY registers. As an example, the opcode 26h followed by an immediate byte value (LD H,n) will load that value into the H register. Preceding this two-byte instruction with the IX register's opcode prefix DD, would instead result in the most significant 8 bits of the IX register being loaded with that same value.

There are several other undocumented instructions as well.

Instruction execution

As in all microprocessors, each instruction is divided into several steps which are usually termed machine cycles (M-cycles). Z80 needs between one and six M-cycles to execute a particular instruction as each M-cycle corresponds roughly to one memory access and/or internal operation. Many instructions actually end during the M1 of the next instruction which is known as a fetch/execute overlap.

Examples of typical instructions (R=read, W=write)

 Total
M-cycles   instruction           M1        M2         M3         M4         M5           M6

  1         INC BC             opcode
  2         ADD A,100          opcode     100
  3         ADD HL,DE          opcode   internal   internal
  4         SET 5,(HL)         prefix    opcode   R(HL), set   W(HL)
  5         LD (IX+102),103    prefix    opcode      102      103,add    W(IX+102)
  6         INC (IY+104)       prefix    opcode      104        add    R(IY+104),inc   W(IY+104)

The Z80 machine cycles are sequenced by an internal state machine which builds each M-cycle out of 3,4,5 or 6 discrete steps (i. e. clock cycles) depending on context. This avoids cumbersome asynchronous logic and makes the control signals behave consistently at a wide range of clock frequencies. Naturally, it also means that a higher frequency crystal must be used than without this subdivision of machine cycles (approximately 2-3 times higher). It does not imply tighter requirements on memory access times however, as a high resolution clock allows more precise control of memory timings and memory therefore can be active in parallel with the CPU to a greater extent (i. e. sitting less idle), allowing more efficient use of available memory performance. For instruction execution, the Z80 combines two full clock cycles into a long memory access period (the M1-signal) which would typically last only a fraction of a (longer) clock cycle in a more asynchronous design (such as the 6800, or similar). The 6800 is an 8-bit Microprocessor produced by Motorola and released shortly after the Intel 8080 in late 1974

Memory, especially EPROM, but also Flash, were generally slow as compared to the state machine sub-cycles (clock cycles) used in contemporary microprocessors. An EPROM, or E rasable P rogrammable '''''R'''ead-'''O'''nly '''M'''emory'', is a type of memory chip that retains its Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed The shortest machine cycle that could safely be used in embedded designs has therefore often been limited by memory access times, not by the maximum CPU frequency (especially so during the home computer era). However, this relation has slowly changed during the last decades, particularly regarding SRAM; cacheless single cycle designs such as the eZ80 have therefore become much more meaningful recently. Static random access memory (SRAM is a type of Semiconductor memory where the word static indicates that unlike ''dynamic'' RAM (DRAM, it does not The ZiLOG eZ80 is an 8-bit Microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor

Compatible peripherals

Zilog introduced a number of peripheral parts for the Z80, which all supported the Z80's interrupt handling system and I/O address space. These included the CTC (Counter-Timer-Circuit), the SIO (Serial Input Output), the DMA (Direct Memory Access), the PIO (Parallel Input-Output) and the DART (Dual Asynchronous Receiver Transmitter). As the product line developed, low-power, high-speed and CMOS versions of these chips were produced. Complementary metal–oxide–semiconductor ( CMOS) (pronounced "see-moss" siːmɔːs ˈsiːmɒs is a major class of Integrated circuits CMOS technology

In the same manner as the x86 family, but unlike contemporary 8-bit processors, like the Motorola 6800 and Mos Technology 6502, the Z80 and 8080 had a separate control line and address space for I/O instructions. While some Z80-based computers used "Motorola-style" memory mapped input/output devices, usually the I/O space was used to address one of the many Zilog peripheral chips compatible with the Z80. The Osborne 1 was the first commercially successful portable Microcomputer, released in April 1981 by Osborne Computer Corporation. Zilog I/O chips supported the Z80's new mode 2 interrupts (see description above) which simplified interrupt handling for large numbers of peripherals.

Undocumented 16 bit I/O-addressing

The Z80 was officially described as supporting 16 bit (64 KB) memory addressing, and 8 bit (256 ports) I/O-addressing. Looking carefully at the hardware reference manual, it can be seen that several I/O instructions, OUT (C),A for example, assert the contents of the entire 16 bit BC register to the address bus. A design could choose decode the entire 16 bit address bus on I/O operations in order to take advantage of this feature, though the code must then avoid the use of I/O instructions which do not send a 16 bit address. This feature has also been used to minimise decoding hardware requirements, such as in the Amstrad CPC and ZX81. The Amstrad CPC is a series of 8-bit Home computers produced by Amstrad Plc during the 1980s and early 1990s The Sinclair ZX81 Home computer, released by Sinclair Research in 1981, was the follow up to the company's ZX80.

Second sources, derivatives etc.

Second sources

NEC's μPD780C Z80 clone on a ZX Spectrum board.
NEC's μPD780C Z80 clone on a ZX Spectrum board. is a Japanese multinational IT company headquartered in Minato Tokyo, Japan. The NEC µPD780C was a fully compatible version of the original NMOS version of the ZiLOG Z80 processor The Sinclair ZX Spectrum is an 8-bit personal Home computer released in the United Kingdom in 1982 by Sinclair Research Ltd
Sharp's LH0080A Z80 clone
Sharp's LH0080A Z80 clone
The T34BM1, a Soviet Z80 clone.
The T34BM1, a Soviet Z80 clone. () is a Japanese Electronics manufacturer founded in 1912 It takes its name from one of its founder's first inventions the Ever-Sharp Mechanical pencil, which
The Toshiba TMPZ84C015 - a plain Z80 with many peripheral- and other functions on chip.
The Toshiba TMPZ84C015 - a plain Z80 with many peripheral- and other functions on chip.
Hitachi HD64180
Hitachi HD64180

Mostek MK3880 and SGS-Thomson Z8400 (now ST Microelectronics) were both second-sources for the Z80. Mostek Podlaskie Voivodeship Mostek was an Integrated circuit manufacturer founded in 1969 by ex-employees of Texas Instruments. STMicroelectronics (,)is an franco-italian Electronics and Semiconductor manufacturer headquartered in in Geneva, Switzerland. STMicroelectronics (,)is an franco-italian Electronics and Semiconductor manufacturer headquartered in in Geneva, Switzerland. Sharp and NEC developed clones in NMOS, the LH-0080 and µPD780C respectively. () is a Japanese Electronics manufacturer founded in 1912 It takes its name from one of its founder's first inventions the Ever-Sharp Mechanical pencil, which is a Japanese multinational IT company headquartered in Minato Tokyo, Japan. The Sharp LH-0080 was a fully compatible version of the original NMOS version of the ZiLOG Z80 processor The NEC µPD780C was a fully compatible version of the original NMOS version of the ZiLOG Z80 processor Toshiba made a CMOS-version, the TMPZ84C00, which is believed (but not verified) to be the same design also used by Zilog for its own CMOS Z84C00. ( is a multinational conglomerate manufacturing company headquartered in Tokyo, Japan. Complementary metal–oxide–semiconductor ( CMOS) (pronounced "see-moss" siːmɔːs ˈsiːmɒs is a major class of Integrated circuits CMOS technology There were also Z80-chips marked GoldStar and LG. GoldStar was an electronics company established in 1958. The corporate name was changed to LG Electronics and LG Cable in 1995.

In East Germany, an unlicensed clone of the Z80, known as the U880, was manufactured. The German Democratic Republic ( GDR; Deutsche Demokratische Republik DDR; commonly known in English as East Germany) was a Socialist state The U880 was an 8-bit Microprocessor manufactured in the German Democratic Republic. It was very popular and was used in Robotron's and VEB Mikroelektronik Mühlhausen's computer systems (e. This article is about the East German company For the Australian company see Robotron Group. g. the KC85-series) and also in many self-made computer systems (ex. The KC 85 ('KC' meaning "Kleincomputer" or "small computer" were models of Microcomputers built in East Germany, first in 1984 by Robotron COMP JU+TER). In Romania another unlicensed clone could be found, named MMN80CPU and produced by Microelectronica, used in home computers like TIM-S, HC, COBRA. Romania ( dated: Rumania, Roumania MMN80CPU is a Z80A Microprocessor clone, working at 35 MHz. It was produced during 1980s at Microelectronica Bucharest

Also, several fully compatible clones of Z80 were created in the Soviet Union, notable ones being the T34BM1, also called КP1858ВМ1. The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 The first marking was used in pre-production series, while the second had to be used for a larger production. Though, due to the collapse of Soviet microelectronics in late 80's, there are much more T34BM1's than КP1858ВМ1's. This CPUs are not full 'clones' of the Z80, they have different behaviour in some situations. They are said to be made for Soviet ZX Spectrum clones, due to their correct work in these computers. Another Soviet CPU, the КP580ИK80 (later marked as КP580ВМ80), was a clone of the Z80's predecessor, the Intel 8080. The KR580VM80A (КР580ВМ80А was a Soviet Microprocessor, a clone of the Intel 8080 CPU.

Derivatives

Fully compatible with the original Z80:

Non, or partially, compatible:

No longer produced:

FPGA and ASIC versions

A commercial, functionally equivalent, CPU core is the Evatronix CZ80CPU, available as synthesizable VHDL or Verilog source code, for high volume ASICs, or as post-synthesis EDIF netlists, for low volume FPGAs from Actel, Altera, Lattice or Xilinx. In the Semiconductor and electronic design industry Verilog is a Hardware description language (HDL used to model electronic systems. EDIF stands for Electronic Design Interchange Format, and has been predominantly used as a vendor neutral format in which to store Electronic Netlists and schematics The word netlist can be used in several different contexts but perhaps the most popular is in the field of Electronic design. FPGAs should not be confused with the Flip-chip pin grid array, a form of integrated circuit packaging Actel Corporation ( is a manufacturer of single-chip FPGA solutions Altera Corporation ( is one of the two major manufacturer of high-end PLDs ( Programmable logic devices, along with Xilinx. Lattice Semiconductor Corporation ( is a United States based manufacturer of high-performance Programmable logic devices ( FPGAs, CPLDs & SPLDs Xilinx Inc ( is the world's largest developer and fabless manufacturer of a class of reconfigurable hardware chips known as Field-programmable gate arrays

Free versions are the T80 and TV80, available as VHDL and Verilog sources under a BSD style license. In the Semiconductor and electronic design industry Verilog is a Hardware description language (HDL used to model electronic systems. The VHDL version, once synthesized, can be clocked up to 35 MHz on a Xilinx Spartan II FPGA. Xilinx Inc ( is the world's largest developer and fabless manufacturer of a class of reconfigurable hardware chips known as Field-programmable gate arrays FPGAs should not be confused with the Flip-chip pin grid array, a form of integrated circuit packaging For large production series, it's much cheaper to use a traditional solution (or ASIC) than an FPGA, however.

Software emulation

Software emulation of the Z80 instruction set on modern PCs runs faster than the original Z80 CPU ran and is used for home computer simulators (such as ZX Spectrum and Amstrad CPC) and also for video game emulators such as MAME, which executes 1980s vintage video games. An emulator duplicates (provides an emulation of the functions of one System using a different system so that the second system behaves like (and appears to A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s Simulation is the imitation of some real thing state of affairs or process The Sinclair ZX Spectrum is an 8-bit personal Home computer released in the United Kingdom in 1982 by Sinclair Research Ltd The Amstrad CPC is a series of 8-bit Home computers produced by Amstrad Plc during the 1980s and early 1990s MAME is an Emulator application designed to recreate the Hardware of Arcade game systems in Software, with the intent of preserving gaming The 1980s was the decade spanning from January 1 1980 to December 31 1989. SIMH emulates MITS Altair 8800 computer with Intel 8080, Zilog Z80 or Intel 8086 processors. SIMH is a highly portable multi-system Emulator which runs on Windows, Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD The MITS Altair 8800 was a Microcomputer design from 1975 based on the Intel 8080 CPU and sold as a mail-order kit through advertisements in The Intel 8080 was an early Microprocessor designed and manufactured by Intel. The 8086 is a 16-bit Microprocessor chip designed by Intel and introduced on the market in 1978 which gave rise to the X86 architecture

Notable uses

In desktop computers

During the late 1970s and early 1980s, the Z80 was used in a great number of fairly anonymous business-oriented machines with the CP/M operating system; a CPU/OS combination that dominated the market in much the same way that Windows based Intel-machines do today. CP/M (Control Program for Microcomputers is an Operating system originally created for Intel 8080 / 85 based Microcomputers by Gary Kildall Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Two well-known examples of Z80+CP/M business computers are the portable Osborne 1 and the Kaypro series. The Osborne 1 was the first commercially successful portable Microcomputer, released in April 1981 by Osborne Computer Corporation. Kaypro Corporation, commonly called Kaypro, was an American home / Personal computer manufacturer of the 1980s Research Machines manufactured the 380Z and 480Z microcomputers which were networked with a thin Ethernet type LAN and CP/NET in 1981. The Research Machines 380Z (often called the RML 380Z or RM 380Z) was an early 8-bit Microcomputer produced by Research Machines Limited Other manufacturers of such systems included Televideo, Xerox and a number of more obscure firms. This article is about TeleVideo Corporation For information on single-unit TV/VCR devices ('televideos' see TV/VCR combo. Xerox Corporation ( (name ˈziːrɒks is a global document management company which manufactures and sells a range of color and black-and-white printers, multifunction Some systems used multi-tasking operating system software to share the one processor between several concurrent users.

Home computers using the Z80 (or equivalent) include the following:

For a comprehensive overview, see the List of home computers using the Z80. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s RadioShack Corporation (formerly Tandy Corporation) (  is a chain of electronics retail stores in the United States, as well as parts of North America TRS-80 was Tandy Corporation 's desktop Microcomputer model line sold through Tandy's Radio Shack stores in the late 1970s and early The Sinclair ZX80 was a Home computer brought to market in 1980 by Sinclair Research of Cambridge England The Sinclair ZX81 Home computer, released by Sinclair Research in 1981, was the follow up to the company's ZX80. The Sinclair ZX Spectrum is an 8-bit personal Home computer released in the United Kingdom in 1982 by Sinclair Research Ltd The Amstrad CPC is a series of 8-bit Home computers produced by Amstrad Plc during the 1980s and early 1990s The Amstrad PCW series ( '''P'''ersonal '''C'''omputer '''W'''ord processor) was British company Amstrad 's versatile line of home/personal Kit beginnings The computer was conceived as a kit with assembly instructions included in Your Computer magazine in June 1982. MSX was the name of a standardized Home computer architecture in the 1980s Spectravideo, or SVI, was a US Computer company founded in 1981 as "SpectraVision" by Harry Fox The SV-318 was the basic model of the Spectravideo range It was fitted with a chiclet style keyboard difficult to use alongside which sat a combination The SV-328 was the business-targeted model of the Spectravideo range sporting a rather crowded full-travel keyboard with Numeric keypad, and no built-in The Jupiter Ace was a British Home computer of the early 1980s produced by a company set up for the purpose named Jupiter Cantab. The ABC 80 (Advanced BASIC Computer 80 was a Home computer engineered by the Swedish corporation Dataindustrier AB (DIAB and manufactured by Luxor The Luxor ABC 800 series were office-versions of the ABC 80 Home computer. The Sharp MZ is a series of Personal computers sold in Japan and Europe (particularly Germany and Great Britain) by Sharp The Galaksija (pronounced Galaxiya, meaning Galaxy) was originally a build-it-yourself Computer designed by Voja Antonić Miles Gordon Technology, known as MGT, was a small British company initially specialising in high-quality add-ons for the Sinclair ZX Spectrum The SAM Coupé is an 8-bit British Home computer that was first released in late 1989 This is a list of home and office computers by category where the main category is the Home computer 's CPU wordlength (8/16/32/64 bits and the subcategory is the

In embedded systems and consumer electronics

The Zilog Z80 has long been a popular microprocessor in embedded systems and microcontroller cores, where it remains in widespread use today. An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints A microcontroller (also MCU or µC is a functional Computer system-on-a- chip. The following list provides examples of such applications of the Z80, including uses in consumer electronics products. Consumer electronics include electronic equipment intended for everyday use

Industrial/professional:

Consumer electronics:

Musical instruments etc:

See also

Articles about the Z80 microprocessor

Articles about Z80 architecture

Educational uses

Scientific Applications

Footnotes

  1. ^ Margins are great, and most chips actually works well at significantly higher (such as 2x) clock frequencies than specified; memory speed has often been the real (physical) limiting factor up until the last 15 years or so, when cheaper and faster available memory chips changed this relation.
  2. ^ According to one of the designers, Masatoshi Shima, the market focus was on high performance printers, high-end cash registers, and intelligent terminals. Masatoshi Shima (嶋正利 Shima Masatoshi, born on August 22[[ 943]] in Shizuoka, Japan) was one of the designers of the world's first Microprocessor
  3. ^ While R is an 8 bit register, it wraps around at 128 instead of 256. If the programmer stores a value in the register, its high bit will be preserved regardless of what the CPU does to the remaining 7 bits. Incorrect implementation of this behaviour is a common source of problems when running games on emulated Z80-machines
  4. ^ Surprisingly, only quite superficial similarities (such as the word MOV, or the letter X, for extended register) exists between the 8080 and 8086 assembly languages, despite the fact that 8080 programs can be compiled into x86 code (using a special assembler).
  5. ^ The 10-year-newer microcoded Z180 design could initially afford more "chip area", permitting a slightly more efficient implementation (using a wider ALU, among other things), similar things can be said for the Z800, Z280, and Z380. The Zilog Z180 8-bit processor is a successor of the Z80 CPU It is compatible with the large base of software written for the Z80 In Computing, an arithmetic logic unit ( ALU) is a Digital circuit that performs Arithmetic and Logical operations The Zilog Z280 was an enhancement of the Zilog Z80 architecture introduced in July 1987, basically a slighly improved CMOS version of the earlier NMOS The Z380 is Zilog 's 32 bit processor from 1994. The Z380 is Z80 compatible but the newer and faster eZ80 family has been more successful However, it was not until the fully pipelined eZ80 was launched in 2001 that those instructions finally became approximately as cycle-efficient as it is technically possible to make them, i. The ZiLOG eZ80 is an 8-bit Microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. e. given the Z80 encodings combined with the capability to do an 8-bit read or write every clock cycle.
  6. ^ A retroactive "home computer" comparison: The Z80 takes 11 clocks for a 16-bit addition; the popular 6502 needs around 20 cycles (see for instance [1]) to do the same thing using 8-bit additions and necessary intermediate storage. The MOS Technology 6502 is an 8-bit Microprocessor that was designed by Chuck Peddle for MOS Technology in 1975 Using "typical" clocks of 4MHz versus 1MHz respectively (i. e. similarly fast memory chips), this translates into the Z80 being approximately seven times as fast as the 6502 for this particular operation (20/(11/4) ≈ 7).
  7. ^ Minicomputer features such as, user and system modes, multiprocessor support, on chip MMU, on chip instruction and data cache, etc. was seen rather as more complexity than as functionality and support for the (usually electronics-oriented) embedded systems designer, it also made it very hard to predict instruction execution times.

External links

References

Zilog Components Data Book, Zilog, Campbell California, 1985, no ISBN

Microprofessor I (MPF 1 introduced in 1981 by Multitech, who changed their company name to Acer in 1987, was their first branded computer
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