The
Zilog Z80 is an
8-bitThe first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
microprocessorA microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
designed by
ZilogZilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...
and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes. The Z80 and its derivatives and clones make up one of the most commonly used
CPUThe central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
families of all time, and, along with the
MOS TechnologyMOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
6502The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
family, dominated the 8-bit microcomputer market from the late 1970s to the mid-1980s.
Zilog licensed the Z80
designIn electronic design a semiconductor intellectual property core, IP core, or IP block is a reusable unit of logic, cell, or chip layout design that is the intellectual property of one party. IP cores may be licensed to another party or can be owned and used by a single party alone...
to several vendors, though many East European and Russian manufacturers made unlicensed copies. This enabled a small company's product to gain acceptance in the world market since
second sourceIn the electronics industry, a second source is a company that is licensed to manufacture and sell components originally designed by another company ....
s from far larger companies such as
Toshibais a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
started to manufacture the device. Consequently, Zilog has made less than 50% of the Z80s since its conception. In recent decades Zilog has refocused on the ever-growing market for
embedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
s (for which the original Z80 and the Z180 were designed) and the most recent Z80-compatible
microcontrollerA microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
family, the fully pipelined
24-bitNotable 24-bit machines include the ICT 1900 series and the Harris H series.The IBM System/360, announced in 1964, was a popular computer system with 24-bit addressing and 32-bit general registers and arithmetic...
eZ80The Zilog eZ80 is an 8-bit microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.The eZ80 is binary compatible with the Z80 and Z180, but almost four times as fast as the original Z80 chip at the same clock frequency...
with a
linearIn mathematics, a linear map or function f is a function which satisfies the following two properties:* Additivity : f = f + f...
16
MBThe megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
address range, has been successfully introduced alongside the simpler Z180 and Z80 products.
Although Zilog made early attempts with advanced mini-computer-like versions of the Z80-architecture (
Z800The Zilog Z800 was a 16-bit microprocessor designed by Zilog to be released in 1985. It was instruction compatible with their existing Z80, and differed primarily in having on chip cache and MMU for a 16 MB address range, and also a huge number of new more orthogonal instructions and addressing modes...
and Z280), these chips never caught on. The company was also trying hard in the
workstationA workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...
market with its Z8000 and
32-bitThe range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
Z80000, both unrelated to the 8-bit Z80.
Brief history and overview
The Z80 came about when
Federico FagginFederico Faggin , who received in 2010 the National Medal of Technology and Innovation by Barack Obama, the highest honor bestowed by the United States government on scientists, engineers, and inventors, at the White House in Washington, is an Italian-born and naturalized U.S...
, after working on the
8080The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
, left Intel at the end of 1974 to found Zilog with Ralph Ungermann, and by July 1976 they had the Z80 on the market. It was designed to be binary compatible with the Intel 8080 so that most 8080 code, notably the
CP/MCP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
operating systemAn operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
, would run unmodified on it.
Masatoshi Shimais a Japanese electronics engineer, who was one of the designers of the world's first microprocessor, the Intel 4004, along with Federico Faggin, Ted Hoff, and Stanley Mazor....
, co-designer of the
4004The Intel 4004 was a 4-bit central processing unit released by Intel Corporation in 1971. It was the first complete CPU on one chip, and also the first commercially available microprocessor...
and the 8080, also contributed to the development of the Z80.
The Z80 offered many real improvements over the 8080:
- An enhanced instruction set
An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...
including bit manipulation, block move, block I/O, and byte search instructions
- New IX and IY index register
An index registerCommonly known as a B-line in early British computers. in a computer's CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations...
s with instructions for direct base+offset addressing
- A better interrupt system
- A more automatic and general vectorized interrupt system
An interrupt vector is the memory address of an interrupt handler, or an index into an array called an interrupt vector table that contains the memory addresses of interrupt handlers...
, mode 2, as well as a fixed vector interrupt system, mode 1, for simple systems with minimal hardware (mode 0 being the 8080-compatible mode).
- A non maskable interrupt (NMI) which can be used to respond to power down situations and/or other high priority events (and allowing a minimalistic Z80 system to easily implement a two-level interrupt scheme in mode 1).
- Two separate register file
A register file is an array of processor registers in a central processing unit . Modern integrated circuit-based register files are usually implemented by way of fast static RAMs with multiple ports...
s, which could be quickly switched, to speed up response to interruptIn computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
s
- Less hardware required for power supply, clock generation and interface to memory and I/O
- Single 5 Volt power supply (the 8080 needed -5V/+5V/+12V)
- Single-phase 5 V clock (the 8080 needed a two-phase high-amplitude clock generator)
- A built-in DRAM
Dram or DRAM may refer to:As a unit of measure:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dirham, a unit of currency in several Arab nationsOther uses:...
refreshMemory 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. Each memory refresh cycle refreshes a succeeding area of memory. Memory refresh is most often associated with...
mechanism that would otherwise have to be provided by external circuitry
- Non-multiplexed buses (the 8080 had state-signals multiplexed onto the data bus)
The Z80 took over from the 8080 and its offspring, the
8085The Intel 8085 is an 8-bit microprocessor introduced by Intel in 1977. It was binary-compatible with the more-famous Intel 8080 but required less supporting hardware, thus allowing simpler and less expensive microcomputer systems to be built....
, in the processor market, and became one of the most popular 8-bit CPUs. Perhaps a key to the initial success of the Z80 was the built-in DRAM refresh, and other features which allowed systems to be built with fewer support chips (later on, most Z80 systems have been
embedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
s, which typically uses static RAM and hence does not need this refresh).
For the original
NMOSN-type metal-oxide-semiconductor logic uses n-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...
design, the specified upper clock frequency limit increased successively from the introductory 2.5 MHz, via the well known 4 MHz (Z80A), up to 6 (Z80B) and 8 MHz (Z80H).
A
CMOSComplementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
version was also developed with specified frequency limits ranging from 4 MHz up to 20 MHz for the version sold today. The CMOS version also allowed a low-power sleep with internal state retained (having no
lower frequency limit). The fully compatible derivatives
HD64180The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit . The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the Zilog Z180. It has the following features:* Memory...
/Z180 and eZ80 are currently specified for up to 33 and 50 MHz respectively.
Programming model and register set
The programming model and register set are conventional and similar to the related x86 family. The
8080The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
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. This feature was present in the
Datapoint 2200The Datapoint 2200 was a mass-produced programmable terminal, designed by Phil Ray and Gus Roche, announced by Computer Terminal Corporation in June, 1970...
but was not implemented by Intel in the 8008. The dual-register set makes sense as the Z80 (like most microprocessors at the time) was really intended for
embeddedAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
use, not for personal computers, or the yet-to-be invented home computers. According to one of the designers,
Masatoshi Shimais a Japanese electronics engineer, who was one of the designers of the world's first microprocessor, the Intel 4004, along with Federico Faggin, Ted Hoff, and Stanley Mazor....
, the market focus was on high performance printers, high-end cash registers, and intelligent terminals. It also turned out to be quite useful for heavily optimized manual assembly coding. Some software, especially games for the
MSXMSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
, Sinclair ZX Spectrum and other Z80 based computers took Z80 assembly optimization to rather extreme levels, employing the duplicated registers among other things.
Registers:
Like on the 8080, 8-bit registers are typically coupled to provide 16-bit versions. The 8080 compatible registers are:
-
AF: 8-bit accumulatorIn a computer's central processing unit , an accumulator is a register in which intermediate arithmetic and logic results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation to main memory, perhaps only to be read right back again for...
(A) and flag bits (F) carry, zero, minus, parity/overflow, half-carry (used for BCDIn computing and electronic systems, binary-coded decimal is a digital encoding method for numbers using decimal notation, with each decimal digit represented by its own binary sequence. In BCD, a numeral is usually represented by four bits which, in general, represent the decimal range 0 through 9...
), and an Add/Subtract flag (usually called N) also for BCD
-
BC: 16-bit data/address register or two 8-bit registers
-
DE: 16-bit data/address register or two 8-bit registers
-
HL: 16-bit accumulator/address register or two 8-bit registers
-
SP: stack pointer, 16 bits
-
PC: program counter, 16 bits
The new registers introduced with the Z80 are:
-
IX: 16-bit index or base register for 8-bit immediate offsets
-
IY: 16-bit index or base register for 8-bit immediate offsets
-
I: interrupt vector base register, 8 bits
-
R: DRAM refresh counter, 8 bits (msbIn computing, the most significant bit is the bit position in a binary number having the greatest value...
does not count)
-
AF': alternate (or shadow) accumulator and flags (toggled in and out with EX AF,AF' )
-
BC', DE' and HL': alternate (or shadow) registers (toggled in and out with EXX)
- Four bits of interrupt status and interrupt mode status
There is no
direct access to the alternate registers; instead, two special instructions,
EX AF,AF' and EXX, each toggles one of two multiplexer flip-flopsIn electronics, a flip-flop or latch is a circuit that has two stable states and can be used to store state information. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in sequential logic...
; 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).
The refresh register, R, increments 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. 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 aroundIn computer programming, an integer overflow occurs when an arithmetic operation attempts to create a numeric value that is too large to be represented within the available storage space. For instance, adding 1 to the largest value that can be represented constitutes an integer overflow...
(by connecting INT to A6).
The interrupt vector register, I, is used for the Z80 specific mode 2 interrupts (selected by the IM 2 instruction). It supplies the high byte of the base address for a 128-entry table of service routine addresses which are selected via a pointer sent to the CPU during an interruptIn computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
acknowledge cycle; the low byte of the base address is fixed at zero. The pointer identifies a particular peripheral chip and/or peripheral function or event, where the chips are normally connected in a so called daisy chainIn electrical and electronic engineering a daisy chain is a wiring scheme in which multiple devices are wired together in sequence or in a ring...
for priority resolution. Like the refresh register, this register has also sometimes been used creatively; in interrupt modes 0 and 1 it can be used as simply another 8-bit data register.
Datapoint 2200 and Intel 8008
The first Intel 8008The Intel 8008 was an early byte-oriented microprocessor designed and manufactured by Intel and introduced in April 1972. It was an 8-bit CPU with an external 14-bit address bus that could address 16KB of memory...
assembly languageAn assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
was based on a very simple (but systematic) syntax inherited from the Datapoint 2200The Datapoint 2200 was a mass-produced programmable terminal, designed by Phil Ray and Gus Roche, announced by Computer Terminal Corporation in June, 1970...
design. 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; however, the 8008 was binary compatible with the Datapoint 2200).
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 and so on), within the instruction mnemonic itself (LDA, LHLD and so on), or both at the same time (LDAX B, STAX D and so on).
| Datapoint 2200 & i8008 |
i8080 |
Z80 |
i8086/i8088 |
| before ~1973 |
~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 |
-- |
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.
New syntax
Because Intel had claimed copyright on their assembly mnemonics, a new assembly syntax had to be developed. This time a more systematic approach was used:
- All registers and register pairs are explicitly denoted by their full names
- Parentheses are consistently used to indicate "memory contents at" (indirection, or pointer dereferencing) with the exception of some jump instructions.
- All load and store instructions use the same mnemonic name, LD, for LOAD (a return to the simplistic Datapoint 2200 vocabulary); other common instructions, such as ADD and INC, use the same mnemonic regardless of addressing mode or operand size. This is possible because the operands themselves carry enough information.
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).
Apart from naming differences, and despite a certain discrepancy in basic register structure, the Z80 and 8086The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors...
syntax are virtually isomorphous for a large portion of instructions. Only quite superficial similarities (such as the word MOV, or the letter X, for extended register) exist between the 8080 and 8086 assembly languages, although 8080 programs can be compiled into x86 code using a special assembler.
Instruction set and encoding
The Z80 uses 252 out of the available 256 codes as single byte opcodes ("root instruction"); 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:
- 8-bit arithmetic and logic operations
- 16-bit arithmetic
- 8-bit load
- 16-bit load
- Bit set, reset, and test
- Call, return, and restart
- Exchange, block transfer, and search
- General purpose arithmetic and CPU control
- Input and output
- Jump
- Rotate and shift
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 were copied. 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. The 10-year-newer microcoded Z180 design could initially afford more "chip area", permitting a slightly more efficient implementation (using a wider ALUIn computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...
, among other things), similar things can be said for the Z800The Zilog Z800 was a 16-bit microprocessor designed by Zilog to be released in 1985. It was instruction compatible with their existing Z80, and differed primarily in having on chip cache and MMU for a 16 MB address range, and also a huge number of new more orthogonal instructions and addressing modes...
, Z280, and Z380. However, it was not until the fully pipelined eZ80The Zilog eZ80 is an 8-bit microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.The eZ80 is binary compatible with the Z80 and Z180, but almost four times as fast as the original Z80 chip at the same clock frequency...
was launched in 2001 that those instructions finally became approximately as cycle-efficient as it is technically possible to make them, i.e. given the Z80 encodings combined with the capability to do an 8-bit read or write every clock cycle. 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.
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 pair of 8-bit pair registers, in the same fashion as the HL register, which is accessible either as 16 bits or separately as the High and Low registers. Even the binary opcodes (machine language) were identical, but preceded by a new opcode prefix. 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. A notable exception to this would be instructions similar to LD H,(IX+d) which make use of both the HL and IX or IY registers in the same instruction; in this case the DD prefix is only applied to the (IX+d) portion of the instruction.
There are several other undocumented instructions as well. Undocumented or illegal opcodeAn Illegal Opcode, also called an Undocumented Instruction, is an instruction to a CPU that is not mentioned in any official documentation released by the CPU's designer or manufacturer, which nevertheless has an effect. Illegal opcodes were common on older CPUs designed during the 1970s, such as...
s are not detected by the Z80 and have various effects, some of which are useful. However, as they are not part of the formal definition of the instruction set, different implementations of the Z80 are not guaranteed to work the same way for every undocumented opcode.
Instruction execution
Each instruction is executed in steps that are usually termed machine cycles (M-cycles), each of which can take between three and six clock periods (T-cycles). 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,n |
opcode |
n |
|
|
|
|
| 3 |
ADD HL,DE |
opcode |
internal |
internal |
|
|
|
| 4 |
SET b,(HL) |
prefix |
opcode |
R(HL), set |
W(HL) |
|
|
| 5 |
LD (IX+d),n |
prefix |
opcode |
d |
n,add |
W(IX+d) |
|
| 6 |
INC (IY+d) |
prefix |
opcode |
d |
add |
R(IY+d),inc |
W(IY+d) |
The Z80 machine cycles are sequenced by an internal state machine which builds each M-cycle out of 3, 4, 5 or 6 T-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 6800The 6800 was an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips...
, or similar).
Memory, especially EPROMAn EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
, but also FlashFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
, were generally slow as compared to the state machine sub-cycles (clock cycles) used in contemporary microprocessors. 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 SRAMStatic random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...
; cacheless, single-cycle designs such as the eZ80The Zilog eZ80 is an 8-bit microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.The eZ80 is binary compatible with the Z80 and Z180, but almost four times as fast as the original Z80 chip at the same clock frequency...
have therefore become much more meaningful recently.
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 CMOSComplementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
versions of these chips were produced.
Like the 8080, 8085 and 8086 processors, but unlike processors such as 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 computersThe Osborne 1 was the first commercially successful portable microcomputer, released on April 3, 1981 by Osborne Computer Corporation. It weighed 10.7 kg , cost USD$ 1795, and ran the then-popular CP/M 2.2 operating system...
used "Motorola-style" memory mapped input/outputMemory-mapped I/O and port I/O are two complementary methods of performing input/output between the CPU and peripheral devices in a computer...
devices, usually the I/O space was used to address one of the many Zilog peripheral chips compatible with the Z80. Zilog I/O chips supported the Z80's new mode 2 interrupts 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 all I/O instructions actually assert the entire 16-bit address bus. OUT (C),reg and IN reg,(C) places the contents of the entire 16 bit BC register on the address bus; OUT (n),A and IN A,(n) places the contents of the A register on b8-b15 of the address bus and n on b0-b7 of the address bus. A designer could choose to decode the entire 16 bit address bus on I/O operations in order to take advantage of this feature, or use the high half of the address bus to select subfeatures of the I/O device. This feature has also been used to minimise decoding hardware requirements, such as in the Amstrad CPCThe Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
and ZX81.
Second sources
MostekMostek was an integrated circuit manufacturer, founded in 1969 by ex-employees of Texas Instruments. Initially their products were manufactured in Worcester, Massachusetts, however by 1974 most of its manufacturing was done in the Carrollton, Texas facility on Crosby Road...
MK3880 and SGS-ThomsonSTMicroelectronics is an Italian-French electronics and semiconductor manufacturer headquartered in Geneva, Switzerland.While STMicroelectronics corporate headquarters and the headquarters for EMEA region are based in Geneva, the holding company, STMicroelectronics N.V. is registered in Amsterdam,...
Z8400 (now STMicroelectronicsSTMicroelectronics is an Italian-French electronics and semiconductor manufacturer headquartered in Geneva, Switzerland.While STMicroelectronics corporate headquarters and the headquarters for EMEA region are based in Geneva, the holding company, STMicroelectronics N.V. is registered in Amsterdam,...
) were both second-sources for the Z80. Sharpis a Japanese multinational corporation that designs and manufactures electronic products. Headquartered in Abeno-ku, Osaka, Japan, Sharp employs more than 55,580 people worldwide as of June 2011. The company was founded in September 1912 and takes its name from one of its founder's first...
and NEC developed second sources for the NMOSN-type metal-oxide-semiconductor logic uses n-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...
Z80, the LH0080 and µPD780C respectively. The µPD780C was used in the Sinclair ZX80 and ZX81, original versions of the ZX SpectrumThe ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...
, and several MSXMSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
computers, and in musical synthesizers such as Oberheim OB-8The Oberheim OB-8 is a subtractive analog synthesizer launched by Oberheim in 1983 and discontinued in 1985. It belongs to the OB-X product line of polyphonic compacts synthesizers and is successor to the OB-Xa...
and others. 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 MZThe Sharp MZ is a series of personal computers sold in Japan and Europe by Sharp beginning in 1978.-Overview:...
series.
Toshibais a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
made a CMOSComplementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
-version, the TMPZ84C00, which is believed (but not verified) to be the same design also used by Zilog for its own CMOS Z84C00. There were also Z80-chips made by GoldStarGoldStar was an electronics company established in 1958. The corporate name was changed to LG Electronics and LG Cable in 1995 after merging with Korean competitor Lucky...
(alias LGLG Corp. is the second-largest South Korean conglomerate company following Samsung, and it is headquartered in the LG Twin Towers in Yeouido-dong, Yeongdeungpo-gu, Seoul. LG produces electronics, chemicals, and telecommunications products and operates subsidiaries like LG Electronics, LG Display,...
) and the BU18400 series of Z80-clones (including DMA, PIO, CTC, DART and SIO) in NMOSN-type metal-oxide-semiconductor logic uses n-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...
and CMOSComplementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
made by ROHM Electronics.
In East Germany, an unlicensed clone of the Z80, known as the U880The U880 was an 8-bit microprocessor manufactured in the German Democratic Republic. It was manufactured in NMOS logic technology and encased in a DIL40 package....
, was manufactured. It was very popular and was used in RobotronVEB Kombinat Robotron was the biggest East German electronics manufacturer. It was based in Dresden and employed 68,000 people . It produced personal computers, SM EVM minicomputers, the ESER mainframe computers, several computer peripherals as well as home computers, radios and television...
's and VEB Mikroelektronik Mühlhausen's computer systems (e.g. the KC85-series) and also in many self-made computer systems (ex. COMP JU+TER). In RomaniaRomania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
another unlicensed clone could be found, named MMN80CPUMMN80CPU is a Z80A microprocessor clone, working at 3.5 MHz. It was produced during 1980s at Microelectronica Bucharest for Romanian 8 bit computers such as HC, CIP, JET, TIM-S, CoBra and others....
and produced by Microelectronica, used in home computers like TIM-S, HC, COBRA.
Also, several clones of Z80 were created in the Soviet UnionThe Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
, notable ones being the T34BM1, also called КР1858ВМ1 (parallelling the Russian 8080-clone KR580VM80AThe KR580VM80A was a Soviet microprocessor, a clone of the Intel 8080 CPU. Different versions of this CPU were manufactured beginning in the late 1970s, the earliest known use being in the SM1800 computer in 1979. Production ceased with the fall of the USSR. Initially called the K580IK80 , it was...
) 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 80s, there are many more T34BM1s than КР1858ВМ1s.
Derivatives
Compatible with the original Z80:
- Hitachi
is a Japanese multinational conglomerate headquartered in Marunouchi 1-chome, Chiyoda, Tokyo, Japan. The company is the parent of the Hitachi Group as part of the larger DKB Group companies...
developed the HD64180The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit . The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the Zilog Z180. It has the following features:* Memory...
, a microcoded and partially dynamic Z80 in CMOS, with on chip peripherals and a simple MMU giving a 1 MBThe megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
address space. It was later second sourced by Zilog, initially as the Z64180, and then in the form of the slightly modified Z180 which has bus protocol and timings better adapted to Z80 peripheral chips. Z180 has been maintained and further developed under Zilog's name, the newest versions being based on the fully static S180/L180 core with very low power draw and EMI (noise).
- Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
developed the 84 pin Z84013 / Z84C13 and the 100 pin Z84015 / Z84C15 series of "intelligent peripheral controllers", basically ordinary NMOS and CMOS Z80 cores with Z80 peripherals, watch dog timer, power on reset, and wait state generator on the same chip. Manufactured by Sharpis a Japanese multinational corporation that designs and manufactures electronic products. Headquartered in Abeno-ku, Osaka, Japan, Sharp employs more than 55,580 people worldwide as of June 2011. The company was founded in September 1912 and takes its name from one of its founder's first...
as well as Toshiba. These products are today second sourced by Zilog.
- The 32-bit Z80 compatible Zilog Z380, introduced 1994, has survived but never gained real momentum; it is used mainly in telecom equipment.
- Zilog's fully pipelined Z80 compatible eZ80
The Zilog eZ80 is an 8-bit microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.The eZ80 is binary compatible with the Z80 and Z180, but almost four times as fast as the original Z80 chip at the same clock frequency...
with an 8/16/24-bit word length and a linear 16 MB address space was introduced in 2001. It exists in versions with on chip SRAMStatic random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...
and/or flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
, as well as with integrated peripherals. One variant has on chip MAC (media access controller)The media access control data communication protocol sub-layer, also known as the medium access control, is a sublayer of the data link layer specified in the seven-layer OSI model , and in the four-layer TCP/IP model...
, and available software include a TCP/IP stack. In contrast with the Z800 and Z280, there are only a few added instructions (primarily LEAs, PEAs, and variable-address 16/24-bit loads), but instructions are instead executed between 2 and 11 times as clock cycle efficient as on the original Z80 (with a mean value around 3-5 times). It is currently specified for clock frequencies up to 50 MHz.
- Kawasaki
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
developed the binary compatible KL5C8400 which is approximately 1.2-1.3 times as clock cycle efficient as the original Z80 and can be clocked at up to 33 MHz. Kawasaki also produces the KL5C80A1x family, which has peripherals as well as a small RAM on chip; it is approximately as clock cycle efficient as the eZ80 and can be clocked at up to 10 MHz (2006).
- The Chinese Actions Semiconductor's audio processor family of chips (ATJ2085 and others) contains a Z80-compatible MCU together with a 24-bit dedicated DSP processor. These chips are used in many MP3 and media player products.
Non-compatible:
- The Toshiba TLCS
The Toshiba TLCS series are a family of CISC and RISC microcontrollers from Toshiba.- TLCS-47 Family :The microcontrollers in the TLCS-47 family are 4-bit systems...
900 series of high volume (mostly OTP) microcontrollers are based on the Z80; they share the same basic BC,DE,HL,IX,IY register structure, and largely the same instructions, but are not binary compatible, while the previous TLCS 90 is Z80-compatible.
- The NEC 78K series microcontrollers are based on the Z80; they share the same basic BC,DE,HL register structure, and has similar (but differently named) instructions; not binary compatible.
Partly compatible:
- Rabbit Semiconductor
Rabbit Semiconductor is the company which designs and sells the Rabbit family of microcontrollers and microcontroller modules.For development, it provides Dynamic C, a non-standard dialect of C with proprietary structures for multitasking....
's Rabbit 2000/3000/4000The Rabbit 2000 is a high-performance 8-bit microcontroller designed by Rabbit Semiconductor expressly to power embedded system applications. Its extensive integrated feature set and glueless architecture facilitate rapid hardware design, and its C-friendly instruction set permits efficient...
microprocessors/microcontrollers are based on the HD64180The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit . The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the Zilog Z180. It has the following features:* Memory...
/Z180 architecture, although they are not fully binary compatible.
No longer produced:
- The ASCII Corporation R800 was a fast 16-bit processor used in MSX TurboR computers; it was software, but not hardware compatible with the Z80 (signal timing, pinout & function of pins differ from the Z80).
- Zilog's ill-fated NMOS Z800
The Zilog Z800 was a 16-bit microprocessor designed by Zilog to be released in 1985. It was instruction compatible with their existing Z80, and differed primarily in having on chip cache and MMU for a 16 MB address range, and also a huge number of new more orthogonal instructions and addressing modes...
and CMOS Z280The Zilog Z280 was an enhancement of the Zilog Z80 architecture introduced in July 1987, basically a slightly improved CMOS version of the earlier NMOS Zilog Z800, both versions were commercial failures...
were quite fast Z80-implementations (before the HD64180The HD64180 is a Z80-based embedded microprocessor developed by Hitachi with an integrated memory management unit . The Hitachi HD64180 "Super Z80" was later licensed to Zilog and sold by them as the Z64180 and with some enhancements as the Zilog Z180. It has the following features:* Memory...
/ Z180) with a 16 MB paged MMU address space; they added many orthogonalizations and addressing modes to the Z80 instruction set, but were too complex and mini-computer inspired to be a natural choice for most embedded applications. Minicomputer features such as, user and system modes, multiprocessor support, on chip MMU, on chip instruction and data cache and so on 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. In contrast, the plain CMOS Z80 has remained popular, alongside the compatible Z180 and eZ80The Zilog eZ80 is an 8-bit microprocessor which is essentially an updated version of the company's earlier Z80 8-bit microprocessor.The eZ80 is binary compatible with the Z80 and Z180, but almost four times as fast as the original Z80 chip at the same clock frequency...
families.
FPGA and ASIC versions
A commercial, functionally equivalent, CPU core is the Evatronix CZ80CPU, available as synthesizable VHDL or VerilogIn the semiconductor and electronic design industry, Verilog is a hardware description language used to model electronic systems. Verilog HDL, not to be confused with VHDL , is most commonly used in the design, verification, and implementation of digital logic chips at the register-transfer level...
source code, for high-volume ASICASIC may refer to:* Application-specific integrated circuit, an integrated circuit developed for a particular use, as opposed to a customised general-purpose device.* ASIC programming language, a dialect of BASIC...
s, or as post-synthesis EDIFEDIF is a vendor-neutral format in which to store Electronic netlists and schematics. It was one of the first attempts to establish a neutral data exchange format for the electronic design automation industry. The goal was to establish a common format from which the proprietary formats of the EDA...
netlistThe word netlist can be used in several different contexts, but perhaps the most popular is in the field of electronic design. In this context, a "netlist" describes the connectivity of an electronic design....
s, for low-volume FPGAs from ActelActel Corporation is a manufacturer of nonvolatile, low-power FPGAs, mixed-signal FPGAs, and programmable logic solutions...
, AlteraAltera Corporation is a Silicon Valley manufacturer of PLDs . The company offered its first programmable logic device in 1984. PLDs can be reprogrammed during the design cycle as well as in the field to perform multiple functions, and they support a fairly fast design process...
, LatticeLattice Semiconductor Corporation is a United States based manufacturer of high-performance programmable logic devices . Founded in 1983, the company employs about 700 people and has annual revenues of around $300 million, with Darin Billerbeck as the chief executive officer...
or XilinxXilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array and as the first semiconductor company with a fabless manufacturing model....
.
Free versions are the T80 and TV80, available as VHDL and Verilog sources under a BSD style license. The VHDL version, once synthesized, can be clocked up to 35 MHz on a XilinxXilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array and as the first semiconductor company with a fabless manufacturing model....
Spartan II FPGA. For large production series, it is much cheaper to use a traditional solution (or ASIC) than an FPGA, however.
Software emulation
Software emulationIn computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
of the Z80 instruction set on modern PCs runs faster than the original Z80 CPU ran and is used for home computerHome computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
simulators (such as Amstrad CPCThe Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
, MSXMSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
and Sinclair ZX Spectrum) and also for video game emulators such as MAMEMAME is an emulator application designed to recreate the hardware of arcade game systems in software on modern personal computers and other platforms. The intention is to preserve gaming history by preventing vintage games from being lost or forgotten...
, which executes arcade video games. SIMHSIMH is a highly portable, multi-system emulator which runs on Windows, Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD, OpenVMS, and other operating systems...
emulates MITS Altair 8800The MITS Altair 8800 was a microcomputer design from 1975 based on the Intel 8080 CPU and sold by mail order through advertisements in Popular Electronics, Radio-Electronics and other hobbyist magazines. The designers hoped to sell only a few hundred build-it-yourself kits to hobbyists, and were...
computer with Intel 8080The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
, Zilog Z80 or Intel 8086The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors...
processors.
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/MCP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
operating system, a combination that dominated the market at the time.
Two well-known examples of Z80+CP/M business computers are the portable Osborne 1The Osborne 1 was the first commercially successful portable microcomputer, released on April 3, 1981 by Osborne Computer Corporation. It weighed 10.7 kg , cost USD$ 1795, and ran the then-popular CP/M 2.2 operating system...
and the KayproKaypro Corporation, commonly called Kaypro, was an American home/personal computer manufacturer of the 1980s. The company was founded by Non-Linear Systems to develop computers to compete with the then-popular Osborne 1 portable microcomputer...
series. Research MachinesRM plc is a British company specialising in providing products and services to schools, colleges, universities and government education departments & agencies...
manufactured the 380Z and 480Z microcomputers which were networked with a thin Ethernet type LAN and CP/NET in 1981. Other manufacturers of such systems included TelevideoTeleVideo Corporation is a U.S. company that achieved its peak of success in the early 1980s producing computer terminals. TeleVideo was founded in 1979 by K. Philip Hwang, a Utah State University graduate born in North Korea who had run a business producing CRT monitors for arcade games since 1975...
, XeroxXerox Corporation is an American multinational document management corporation that produced and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies...
(820 rangeThe Xerox 820 was an 8-bit desktop computer sold by Xerox in the early 1980s. The computer ran under the CP/M operating system and used floppy disk drives for mass storage...
) and a number of more obscure firms. Some systems used multi-tasking operating system software to share the one processor between several concurrent users.
The Radio ShackRadio shack is a slang term for a room or structure for housing radio equipment.-History:In the early days of radio, equipment was experimental and home-built. The first radio transmitters used a noisy spark to generate radio waves and were often housed in a garage or shed. When radio was first...
TRS-80TRS-80 was Tandy Corporation's desktop microcomputer model line, sold through Tandy's Radio Shack stores in the late 1970s and early 1980s. The first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December. The line won popularity with...
, introduced in 1977, used the Z80, as did the follow on Models II,III,IV and proposed Model V. In the United Kingdom, Sinclair Research used the Z80 and Z80A in its ZX80, ZX81 and ZX SpectrumThe ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...
home computers, and AmstradAmstrad is a British electronics company, now wholly owned by BSkyB. As of 2006, Amstrad's main business is manufacturing Sky Digital interactive boxes....
used them in their Amstrad CPCThe Amstrad CPC is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
line.
The Commodore 128The Commodore 128 home/personal computer was the last 8-bit machine commercially released by Commodore Business Machines...
featured a Z80 processor alongside its MOS Technology 8502The MOS Technology 8502 was an 8-bit microprocessor designed by MOS Technology and used in the Commodore 128. Based on the MOS 6510 that was used in the Commodore 64, the 8502 added the ability to run at a double clock rate, in addition to the standard 1.024 MHz rate used by the Commodore 64.Since...
processor for CP/M compatibility.
Other 6502The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
architecture computers on the market at the time, such as the BBC MicroThe BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...
, Apple IIThe Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
and the 6510thumb|300px|Image of the internals of a [[Commodore 64]] showing the 6510 CPU . The chip on the right is the [[MOS Technology SID|6581 SID]]...
based Commodore 64The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
,
could make use of the Z80 with an external unit, a plug-in card, or an expansion cartridge. The MicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
Z-80 SoftCardThe Z-80 SoftCard was a plug-in card supplied by Microsoft for use with the Apple II personal computer, which did not have a Z-80 compatible processor and could not run CP/M. It had a Zilog Z80 CPU plus some 74LS00 series TTL chips to adapt that processor's bus to the rather different bus system...
for the Apple II was a particularly successful add-on card and one of Microsoft's few hardware products of the era.
AcerAcer Incorporated is a multinational information technology and electronics corporation headquartered in Xizhi, New Taipei City, Taiwan. Acer's products include desktop and laptop PCs, tablet computers, servers, storage devices, displays, smartphones and peripherals...
, formerly Multitech, introduced the Microprofessor IThe Micro-Professor MPF-I, introduced in 1981 by Multitech , was the first branded computer product from Multitech and probably one of the world's longest selling computers...
, in 1981. It was designed as a simple and inexpensive training system for the Z80 microprocessor. Currently, it is still being manufactured and sold by Flite Electronics International Limited in Southampton, England
Embedded systems and consumer electronics
The Zilog Z80 has long been a popular microprocessor in embedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
s and microcontrollerA microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
cores, where it remains in widespread use today. The following list provides examples of such applications of the Z80, including uses in consumer electronics products.
Industry
- Office equipment such as matrix printers, fax machines, answering machine
The answering machine or message machine, also known as the telephone answering machine in the UK and some Commonwealth countries) and previously known as an ansaphone, ansafone, or telephone answering device is a device for answering telephones and recording callers' messages.Unlike voicemail,...
s, and photocopiers are known examples.
- Industrial programmable logic controller
A programmable logic controller or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines...
s (PLCs) use the Z80 in CPU modules, for auxiliary functions such as analog I/O, or in communication modules.
- It has also been employed in robots, for example for speech recognition and low level tasks such as servo processors
A servo drive is a special electronic amplifier used to power electric servomechanisms.A servo drive monitors the feedback signal from the servomechanism and continually adjusts for deviation from expected behavior.-Function:...
in pick and place machines.
- RS232 multiplexers connecting large numbers of old style "terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
s" to minicomputers or mainframes used arrays of Z80 CPU/SIO boards.
- Applications such as TV broadcast
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
vision mixerA vision mixer is a device used to select between several different video sources and in some cases Compositing video sources together to create special effects...
s have used the Z80 for embedded real timeIn computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
subtasks.
- It has also been used in Seagate Technology
Seagate Technology is one of the world's largest manufacturers of hard disk drives. Incorporated in 1978 as Shugart Technology, Seagate is currently incorporated in Dublin, Ireland and has its principal executive offices in Scotts Valley, California, United States.-1970s:On November 1, 1979...
's and other manufacturers' hard diskA hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
s.
- Credit card
A credit card is a small plastic card issued to users as a system of payment. It allows its holder to buy goods and services based on the holder's promise to pay for these goods and services...
consoles controlling fuel pumps used Z80 CPU and PIOs (US patents 4930665, 4962462 and 5602745).
- Several PC expansion cards, such as Adaptec
Adaptec is a computer hardware brand owned by PMC-Sierra that is used on some of its host adapters for connecting storage devices to computers. The production line of Adaptec is in Indonesia. Products are made to interface with SCSI, Serial ATA, and Serial attached SCSI. Some of its host adapters...
s SCSISmall Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
boards, have been using the Z80/Z180 and peripheral chips.
- Z80/Z180/Z380 have been used in telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
equipment such as telephone switches and various kinds of modemA modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
s.
- The Stofor
Stofor, pronounced as in "Stow Four", is a store and forward message switching system designed by Fenwood Designs Ltd, UK in 1980.-Market and specification:...
message switch, used extensively by banks and brokers in the UK was Z80 based.
- Cash registers and store management systems
- Home automation, wireless sprinkler control and wireless mesh using the N8VEM open source homebrew system.
- Breathalyzer
A breathalyzer or breathalyser is a device for estimating blood alcohol content from a breath sample...
equipment used by law enforcement agencies.
Consumer electronics
- Various scientific
A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science, engineering, and mathematics...
and graphing calculatorA graphing calculator typically refers to a class of handheld calculators that are capable of plotting graphs, solving simultaneous equations, and performing numerous other tasks with variables...
s use the Z80, including the Texas InstrumentsTexas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
TI-73, TI-81The TI-81 is the first graphing calculator made by Texas Instruments. It was designed in 1990 for use in algebra and precalculus courses. Since its original release, it has been superseded several times by newer calculators - the TI-82, the TI-83, the TI-83 Plus, TI-83 Plus Silver Edition, the...
, TI-82The TI-82 is a graphing calculator made by Texas Instruments. The TI-82 was designed in 1993 as a stripped down, more user friendly version of the TI-85, and as a replacement for the TI-81. It was the direct predecessor of the TI-83. It shares with the TI-85 a 6 MHz Zilog Z80 microprocessor...
, TI-83The TI-83 series of graphing calculators is manufactured by Texas Instruments.The original TI-83 is itself an upgraded version of the TI-82. Released in 1996, it is one of the most used graphing calculators for students...
, TI-84The TI-84 Plus is a graphing calculator made by Texas Instruments which was released in early 2004. There is no original TI-84, only the TI-84 Plus and TI-84 Plus Silver Edition models. It is an enhanced version of the TI-83 Plus. The key-by-key correspondence is relatively the same, but the 84...
, TI-85The TI-85 was a graphing calculator made by Texas Instruments based around the Zilog Z80 microprocessor. Designed in 1992 as TI's second graphing calculator , it has since been replaced by the TI-86, which has also been discontinued....
and TI-86The TI-86 is a programmable graphing calculator introduced in 1997 and produced by Texas Instruments. The TI-86 uses the Zilog Z80 microprocessor. It is partially backwards-compatible with its predecessor, the TI-85....
series.
- All the S1 MP3 Player
S1 MP3 players are a type of digital audio players based on many different kinds of chipsets. The popular ones include Actions and ALI chipsets...
type digital audio players use the Z80 instruction set.
- Z80 was often used in coin-operated arcade game
An arcade game is a coin-operated entertainment machine, usually installed in public businesses such as restaurants, bars, and amusement arcades. Most arcade games are video games, pinball machines, electro-mechanical games, redemption games, and merchandisers...
s, and was commonly used as the main CPU, sound or video coprocessors. Pac-Manis an arcade game developed by Namco and licensed for distribution in the United States by Midway, first released in Japan on May 22, 1980. Immensely popular from its original release to the present day, Pac-Man is considered one of the classics of the medium, virtually synonymous with video games,...
arcade games feature a single Z80 as the main CPU. Galaxianis an arcade game developed by Namco in 1979. It was published by Namco in Japan and was imported to North America by Midway in 1980. A fixed shooter-style game in which the player controls a spaceship at the bottom of the screen and shoots enemies descending in various directions, it was designed...
and arcade games such as King & BalloonKing & Balloon is a fixed shooter arcade game that was released by Namco in 1980. It was an early example of dual-core processing, running on Namco Galaxian hardware, based on the Z80 microprocessor, with an extra Z80 microprocessor to drive a DAC for speech; the King speaks when he is captured ,...
and Check ManCheck Man is an arcade game released by Zilec-Zenitone in 1982. While being a fast paced action game, there are puzzle elements to the gameplay. The game uses the Namco Galaxian arcade board.-Gameplay:...
that use the Namco GalaxianThe Namco 8-bit Galaxian arcade system board was first used by Namco in 1979.-Namco Galaxian specifications:*Main CPU: Zilog Z80*Sound chips: Discrete*Video resolution: 256x224...
boardset also use a Z80 as the main CPU. Other Namcois a Japanese corporation best known as a former video game developer and publisher. Following a merger with Bandai in September 2005, the two companies' game production assets were spun off into Namco Bandai Games on March 31, 2006. Namco Ltd. was re-established to continue domestic operation of...
licensed arcade games such as Galagais a fixed shooter arcade game developed and published by Namco in Japan and published by Midway in North America in 1981. It is the sequel to Galaxian, released in 1979. The gameplay of Galaga puts the player in control of a space ship which is situated on the bottom of the screen...
and other games that use the Namco GalagaThe Namco 8-bit Galaga is an arcade game system board. It was first used by Namco in 1981.-Namco Galaga specifications:*Main, graphics and sound CPU : three Z80 processors...
boardset such as Bosconianis a free-roaming multi-directional scrolling shooter arcade game that was developed by Namco and released in 1981. In contrast to the more linear shooter games of its time, Bosconian allows the player's ship to freely move across open space that scrolls in all directions. The game also features a...
, Dig Dugis an arcade game developed and published by Namco in Japan in 1982 for Namco Galaga hardware. It was later published outside of Japan by Atari. A popular game based on a simple concept, it was also released as a video game on many consoles.-Objective:...
, Xeviousis a vertical scrolling shooter arcade game by Namco, released in 1982. It was designed by Masanobu Endō. In the U.S., the game was manufactured and distributed by Atari. Xevious runs on Namco Galaga hardware. In Brazil the arcade cabinet was printed with the name 'COLUMBIA' for the game, while the...
, and Super Xeviousalso is a vertical scrolling shooter arcade game that was released by Namco in 1984. As the name suggests, it is the sequel to Xevious, which was released 2 years earlier.-Gameplay:...
use three Z80 microprocessors running in parallel for the main CPU, graphics, and sound.
- It was also found in home video game consoles such as the ColecoVision
The ColecoVision is Coleco Industries' second generation home video game console which was released in August 1982. The ColecoVision offered arcade-quality graphics and gaming style, and the means to expand the system's basic hardware...
, Sega Master SystemThe is a third-generation video game console that was manufactured and released by Sega in 1985 in Japan , 1986 in North America and 1987 in Europe....
and Sega Game GearThe was Sega's first handheld game console. It was the third commercially available color handheld console, after the Atari Lynx and the TurboExpress....
video game consoleA video game console is an interactive entertainment computer or customized computer system that produces a video display signal which can be used with a display device to display a video game...
s, as an audio co-processor in the Sega Mega DriveThe Sega Genesis is a fourth-generation video game console developed and produced by Sega. It was originally released in Japan in 1988 as , then in North America in 1989 as Sega Genesis, and in Europe, Australia and other PAL regions in 1990 as Mega Drive. The reason for the two names is that...
and as an audio controller and co-processor to the Motorola 68000 in the SNKSNK Playmore Corporation is a Japanese video game hardware and software company. SNK is an acronym of , which was SNK's original name. The company's legal and trading name became SNK in 1986....
Neo-GeoThe is a cartridge-based arcade and home video game system released on July 1, 1991 by Japanese game company SNK. Being in the Fourth generation of Gaming, it was the first console in the former Neo Geo family, which only lived through the 1990s...
.
- Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
's Game BoyThe , is an 8-bit handheld video game device developed and manufactured by Nintendo. It was released in Japan on , in North America in , and in Europe on...
and Game Boy ColorThe is Nintendo's successor to the 8-bit Game Boy handheld game console, and was released on October 21, 1998 in Japan, November 19, 1998 in North America, November 23, 1998 in Europe and November 27, 1998 in the United Kingdom. It features a color screen and is slightly thicker and taller than...
handheld game systems used a 8008-derived processor with some Z80 instructions added (BIT) as well as unique auto-increment/decrement addressing modes. The CPU was manufactured by Sharp Corporationis a Japanese multinational corporation that designs and manufactures electronic products. Headquartered in Abeno-ku, Osaka, Japan, Sharp employs more than 55,580 people worldwide as of June 2011. The company was founded in September 1912 and takes its name from one of its founder's first...
. Game Boy Color is notable for its ability to selectively double the CPU clock speed when running Game Boy Color software. The Game Boy AdvanceThe is a 32-bit handheld video game console developed, manufactured, and marketed by Nintendo. It is the successor to the Game Boy Color. It was released in Japan on March 21, 2001; in North America on June 11, 2001; in Australia and Europe on June 22, 2001; and in the People's Republic of China...
series of products originally included this same modified Z80 for backward compatibility. However, this changed with the release of the Game Boy Microis a handheld game console developed and manufactured by Nintendo. It was first released in September 2005 in the market. The system is the last console of the Game Boy line...
.
- In Russia, Z80 and its clones were widely used in multi-functional land line phones with Caller ID
Musical instruments
- MIDI sequencers such as E-mu 4060 Polyphonic Keyboard and Sequencer, Zyklus MPS, and Roland
Roland was a Frankish military leader under Charlemagne who became one of the principal figures in the literary cycle known as the Matter of France. Historically, Roland was military governor of the Breton March, with responsibility for defending the frontier of Francia against the Bretons...
MSQ700 were built around the Z80,
- MIDI controllers and switches such as Waldorf Midi-Bay MB-15 and others.
- Several polyphonic analog synthesizer
An analog or analogue synthesizer is a synthesizer that uses analog circuits and analog computer techniques to generate sound electronically. The earliest analog synthesizers in the 1920s and 1930s such as the Trautonium were built with a variety of vacuum-tube and electro-mechanical technologies...
s used it for keyboard-scanning (also wheels, knobs, displays...) and D/A or PWMPulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....
control of analog levels; in newer designs, sometimes sequencing and/or MIDI-communication. The Z80 was also often involved in the sound generation itself; implementing LFOs, envelope generators and so on. Known examples include:
- Sequential Circuits
Sequential Circuits Inc. was a California-based synthesizer company that was founded in the early 1970s by Dave Smith and sold to Yamaha Corporation in 1987. The company, throughout its lifespan, pioneered many groundbreaking technologies and design principles that are often taken for granted in...
Prophet 5, Prophet 10, Prophet 600, Six-Trak, Multitrak, MAX, and Split-8The Split-8 is a polyphonic analogue keyboard synthesizer manufactured by Sequential Circuits. Built in Japan and going by the alternative name "Pro-8" in some markets, this was one of the last synthesizers produced by the company and was assigned model number 608. It was released in 1985 at a list...
- MemoryMoog
The Memorymoog is a polyphonic electronic music synthesizer manufactured by Moog Music from 1981 to 1983, the last polyphonic synthesizer to be released by Moog Music before the company was sold to management and renamed Moog Electronics...
six-voice synthesizer
- Oberheim OB-8
The Oberheim OB-8 is a subtractive analog synthesizer launched by Oberheim in 1983 and discontinued in 1985. It belongs to the OB-X product line of polyphonic compacts synthesizers and is successor to the OB-Xa...
eight-voice synthesizer with MIDI
- Roland Jupiter-8
The Jupiter-8 is an eight-voice polyphonic analog subtractive synthesizer introduced by Roland Corporation in 1981.The Jupiter-8, or JP-8, was Roland's flagship synthesizer for the first half of the 1980's...
eight-voice synthesizer
- Digital sampling
In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave to a sequence of samples ....
synthesizerA synthesizer is an electronic instrument capable of producing sounds by generating electrical signals of different frequencies. These electrical signals are played through a loudspeaker or set of headphones...
s such as the Emulator I, Emulator II, and Akai S700 12-bit Sampler,
- as well as drum machines like the E-mu SP-12, E-mu SP-1200
E-mu SP-1200 is a classic drum machine and sampler released in August 1987 by E-mu Systems, Inc. as an update of the SP-12, which was originally created for dance music producers...
, E-mu Drumulator, and the Sequential CircuitsSequential Circuits Inc. was a California-based synthesizer company that was founded in the early 1970s by Dave Smith and sold to Yamaha Corporation in 1987. The company, throughout its lifespan, pioneered many groundbreaking technologies and design principles that are often taken for granted in...
Drumtraks, used Z80 processors.
- Many Lexicon
Lexicon is an American audio equipment manufacturing company founded in 1971 and owned by Harman International Industries. Lexicon's roots began in 1969 with the founding of American Data Sciences by MIT professor Dr...
reverberators (PCM70, LXP15, LXP1, MPX100) used one or more Z80s for user interface and LFO generation where dedicated hardware provided DSPDigital signal processing is concerned with the representation of discrete time signals by a sequence of numbers or symbols and the processing of these signals. Digital signal processing and analog signal processing are subfields of signal processing...
functions.
- The ADA MP-1. A MIDI controlled, vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
, guitar pre-amplifier.
See also
- Small C
- BDS C
BDS C is a compiler for a sizeable subset of the C programming language, that ran on and generated code for the Intel 8080 and Zilog Z80 processors. It was written by and first released in 1979 when he was 20 years old...
- Small Device C Compiler
The Small Device C Compiler is an open source, partially retargetable C compiler for microcontrollers. It is distributed under the GNU General Public License. The package also contains a linker, assembler, simulator and debugger...
- Z88DK
Z88DK is a Small-C-derived cross compiler for a long list of Z80 based computers. The name derives from the fact that it was originally developed to target the Cambridge Z88...
- MP/M
MP/M was a multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each using a separate terminal....
- SymbOS
SymbOS is a free multitasking operating system for Z80-based 8-bit computer systems. At present it is available for the Amstrad CPC series of computers, as well as for all MSX models starting from the MSX2 standard and for most Amstrad PCW models...
- S-100 bus
The S-100 bus or Altair bus, IEEE696-1983 , was an early computer bus designed in 1974 as a part of the Altair 8800, generally considered today to be the first personal computer...
- List of home computers by category
- Vasm
vasm is a free assembler supporting various CPUs and many different output formats.CPUs officially supported by vasm include M680x0 family, ColdFire family, 80x86 family, PowerPC, ARM family, Z80 family, C16x/ST10, 6502 etc. Vasm supports Standard MIT , Motorola/Freescale 68k and Old 8-bit style...
Further reading
- Microprofessor I
The Micro-Professor MPF-I, introduced in 1981 by Multitech , was the first branded computer product from Multitech and probably one of the world's longest selling computers...
Z80 System hardware, associated coursework & training manuals.
External links