Microprocessor
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A microprocessor is a computer processor where the data processing logic and control is included on a single
integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit. The integrated circuit is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose,
clock A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and t ...
-driven,
register Register or registration may refer to: Arts entertainment, and media Music * Register (music), the relative "height" or range of a note, melody, part, instrument, etc. * ''Register'', a 2017 album by Travis Miller * Registration (organ), th ...
-based,
digital integrated circuit Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals. Digital electronic circuits are usually ...
that accepts
binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that ta ...
data as input, processes it according to instructions stored in its
memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
, and provides results (also in binary form) as output. Microprocessors contain both
combinational logic In automata theory, combinational logic (also referred to as time-independent logic or combinatorial logic) is a type of digital logic which is implemented by Boolean circuits, where the output is a pure function of the present input only. This ...
and sequential digital logic, and operate on numbers and symbols represented in the
binary number A binary number is a number expressed in the base-2 numeral system or binary numeral system, a method of mathematical expression which uses only two symbols: typically "0" (zero) and "1" ( one). The base-2 numeral system is a positional notatio ...
system. The integration of a whole CPU onto a single or a few integrated circuits using Very-Large-Scale Integration (VLSI) greatly reduced the cost of processing power. Integrated circuit processors are produced in large numbers by highly automated metal-oxide-semiconductor (MOS) fabrication processes, resulting in a relatively low
unit price A product's average price is the result of dividing the product's total sales revenue by the total units sold. When one product is sold in variants, such as bottle sizes, managers must define "comparable" units. Average prices can be calculated b ...
. Single-chip processors increase reliability because there are much fewer electrical connections that could fail. As microprocessor designs improve, the cost of manufacturing a chip (with smaller components built on a semiconductor chip the same size) generally stays the same according to
Rock's law Rock's law or Moore's second law, named for Arthur Rock or Gordon Moore, says that the cost of a semiconductor chip fabrication plant doubles every four years. As of 2015, the price had already reached about 14 billion US dollars. Rock's law can be ...
. Before microprocessors, small computers had been built using racks of
circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich struc ...
s with many medium- and small-scale integrated circuits, typically of
TTL TTL may refer to: Photography * Through-the-lens metering, a camera feature * Zenit TTL, an SLR film camera named for its TTL metering capability Technology * Time to live, a computer data lifespan-limiting mechanism * Transistor–transistor lo ...
type. Microprocessors combined this into one or a few large-scale ICs. While there is disagreement over who deserves credit for the invention of the microprocessor, the first commercially available microprocessor was the
Intel 4004 The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs. The 4004 was the first significa ...
, designed by
Federico Faggin Federico Faggin (, ; born 1 December 1941) is an Italian physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group d ...
and introduced in 1971. Continued increases in microprocessor capacity have since rendered other forms of computers almost completely obsolete (see history of computing hardware), with one or more microprocessors used in everything from the smallest
embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...
s and
handheld device A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physical ...
s to the largest mainframes and supercomputers.


Structure

The complexity of an integrated circuit is bounded by physical limitations on the number of
transistors upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
that can be put onto one chip, the number of package terminations that can connect the processor to other parts of the system, the number of interconnections it is possible to make on the chip, and the heat that the chip can
dissipate In thermodynamics, dissipation is the result of an irreversible process that takes place in homogeneous thermodynamic systems. In a dissipative process, energy (internal, bulk flow kinetic, or system potential) transforms from an initial form to ...
. Advancing technology makes more complex and powerful chips feasible to manufacture. A minimal hypothetical microprocessor might include only an arithmetic logic unit (ALU), and a
control logic Control logic is a key part of a software program that controls the operations of the program. The control logic responds to commands from the user, and it also acts on its own to perform automated tasks that have been structured into the program. ...
section. The ALU performs addition, subtraction, and operations such as AND or OR. Each operation of the ALU sets one or more
flag A flag is a piece of fabric (most often rectangular or quadrilateral) with a distinctive design and colours. It is used as a symbol, a signalling device, or for decoration. The term ''flag'' is also used to refer to the graphic design empl ...
s in a
status register A status register, flag register, or condition code register (CCR) is a collection of status flag bits for a processor. Examples of such registers include FLAGS register in the x86 architecture, flags in the program status word (PSW) register in ...
, which indicate the results of the last operation (zero value, negative number, overflow, or others). The control logic retrieves instruction codes from memory and initiates the sequence of operations required for the ALU to carry out the instruction. A single operation code might affect many individual data paths, registers, and other elements of the processor. As integrated circuit technology advanced, it was feasible to manufacture more and more complex processors on a single chip. The size of data objects became larger; allowing more transistors on a chip allowed
word A word is a basic element of language that carries an semantics, objective or pragmatics, practical semantics, meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of w ...
sizes to increase from 4- and 8-bit words up to today's
64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A compu ...
words. Additional features were added to the processor architecture; more on-chip registers sped up programs, and complex instructions could be used to make more compact programs. Floating-point arithmetic, for example, was often not available on 8-bit microprocessors, but had to be carried out in
software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...
. Integration of the
floating-point unit In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can b ...
, first as a separate integrated circuit and then as part of the same microprocessor chip, sped up floating-point calculations. Occasionally, physical limitations of integrated circuits made such practices as a
bit slice Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary ''n''-bit central processing unit (CPU). Each of these co ...
approach necessary. Instead of processing all of a long word on one integrated circuit, multiple circuits in parallel processed subsets of each word. While this required extra logic to handle, for example, carry and overflow within each slice, the result was a system that could handle, for example, 32-bit words using integrated circuits with a capacity for only four bits each. The ability to put large numbers of transistors on one chip makes it feasible to integrate memory on the same die as the processor. This
CPU cache A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, whic ...
has the advantage of faster access than off-chip memory and increases the processing speed of the system for many applications. Processor
clock frequency In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pr ...
has increased more rapidly than external memory speed, so
cache memory In computing, a cache ( ) is a hardware or software component that stores data so that future requests for that data can be served faster; the data stored in a cache might be the result of an earlier computation or a copy of data stored elsewher ...
is necessary if the processor is not to be delayed by slower external memory.


Special-purpose designs

A microprocessor is a general - purpose entity. Several specialized processing devices have followed: * A
digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...
(DSP) is specialized for
signal processing Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing ''signals'', such as audio signal processing, sound, image processing, images, and scientific measurements. Signal processing techniq ...
. *
Graphics processing unit A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, m ...
s (GPUs) are processors designed primarily for realtime rendering of images. * Other specialized units exist for
video processing In electronics engineering, video processing is a particular case of signal processing, in particular image processing, which often employs video filters and where the input and output signals are video files or video streams. Video processing ...
and
machine vision Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry. Machine vision refers to ...
. (See: Hardware acceleration.) * Microcontrollers in
embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...
s and
peripheral device A peripheral or peripheral device is an auxiliary device used to put information into and get information out of a computer. The term ''peripheral device'' refers to all hardware components that are attached to a computer and are controlled by the ...
s. * Systems on chip (SoCs) often integrate one or more microprocessor and microcontroller cores with other components such as radio modems, and are used in smartphones and tablet computers.


Speed and power considerations

Microprocessors can be selected for differing applications based on their word size, which is a measure of their complexity. Longer word sizes allow each
clock cycle In electronics and especially synchronous digital circuits, a clock signal (historically also known as ''logic beat'') oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits. A clock sig ...
of a processor to carry out more computation, but correspond to physically larger integrated circuit dies with higher standby and operating
power consumption Electric energy consumption is the form of energy consumption that uses electrical energy. Electric energy consumption is the actual energy demand made on existing electricity supply for transportation, residential, industrial, commercial, and ot ...
.CMicrotek
"8-bit vs 32-bit Micros"
.
4-, 8- or 12-bit processors are widely integrated into microcontrollers operating embedded systems. Where a system is expected to handle larger volumes of data or require a more flexible
user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...
, 16-, 32- or 64-bit processors are used. An 8- or 16-bit processor may be selected over a 32-bit processor for system on a chip or microcontroller applications that require extremely
low-power electronics Low-power electronics are electronics, such as notebook processors, that have been designed to use less electric power than usual, often at some expense. In the case of notebook processors, this expense is processing power; notebook processors usu ...
, or are part of a
mixed-signal integrated circuit A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die.analog electronics Analogue electronics ( en-US, analog electronics) are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two levels. The term "analogue" describes the proportional relat ...
such as high-resolution analog to digital converters, or both. Some people say that running 32-bit arithmetic on an 8-bit chip could end up using more power, as the chip must execute software with multiple instructions. However, others say that modern 8-bit chips are always more power-efficient than 32-bit chips when running equivalent software routines. Wayne Freeman
"11 Myths About 8-Bit Microcontrollers"
2016. quote: "Basically, by getting your work done faster, you can put the CPU in sleep mode for longer periods of time. Thus, 32-bit MCUs are more power-efficient than 8-bit MCUs, right? Wrong."


Embedded applications

Thousands of items that were traditionally not computer-related include microprocessors. These include household appliances, vehicles (and their accessories), tools and test instruments, toys, light switches/dimmers and electrical circuit breakers, smoke alarms, battery packs, and hi-fi audio/visual components (from
DVD player A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to ...
s to phonograph turntables). Such products as cellular telephones,
DVD video DVD-Video is a consumer video format used to store digital video on DVD discs. DVD-Video was the dominant consumer home video format in Asia, North America, Europe, and Australia in the 2000s until it was supplanted by the high-definition Bl ...
system and
HDTV High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
broadcast systems fundamentally require consumer devices with powerful, low-cost, microprocessors. Increasingly stringent pollution control standards effectively require automobile manufacturers to use microprocessor engine management systems to allow optimal control of emissions over the widely varying operating conditions of an automobile. Non-programmable controls would require bulky, or costly implementation to achieve the results possible with a microprocessor. A microprocessor control program (
embedded software Embedded software is computer software, written to control machines or devices that are not typically thought of as computers, commonly known as embedded systems. It is typically specialized for the particular hardware that it runs on and has tim ...
) can be tailored to fit the needs of a product line, allowing upgrades in performance with minimal redesign of the product. Unique features can be implemented in product line's various models at negligible production cost. Microprocessor control of a system can provide control strategies that would be impractical to implement using electromechanical controls or purpose-built electronic controls. For example, an internal combustion engine's control system can adjust ignition timing based on engine speed, load, temperature, and any observed tendency for knocking—allowing the engine to operate on a range of fuel grades.


History

The advent of low-cost computers on
integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
has transformed
modern society Modernity, a topic in the humanities and social sciences, is both a historical period (the modern era) and the ensemble of particular socio-cultural norms, attitudes and practices that arose in the wake of the Renaissancein the "Age of Reason ...
. General-purpose microprocessors in
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s are used for computation, text editing, multimedia display, and communication over the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
. Many more microprocessors are part of
embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...
s, providing digital control over myriad objects from appliances to automobiles to
cellular phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while ...
s and industrial process control. Microprocessors perform binary operations based on boolean logic, named after
George Boole George Boole (; 2 November 1815 – 8 December 1864) was a largely self-taught English mathematician, philosopher, and logician, most of whose short career was spent as the first professor of mathematics at Queen's College, Cork in ...
. The ability to operate computer systems using Boolean Logic was first proven in a 1938 thesis by master's student
Claude Shannon Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, and cryptographer known as a "father of information theory". As a 21-year-old master's degree student at the Massachusetts Inst ...
, who later went on to become a professor. Shannon is considered "The Father of Information Theory". Following the development of
MOS integrated circuit upright=1.6, gate (G), body (B), source (S), and drain (D) terminals. The gate is separated from the body by an gate oxide">insulating layer (pink). The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also ...
chips in the early 1960s, MOS chips reached higher transistor density and lower manufacturing costs than bipolar
integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
by 1964. MOS chips further increased in complexity at a rate predicted by Moore's law, leading to
large-scale integration An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
(LSI) with hundreds of
transistors upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
on a single MOS chip by the late 1960s. The application of MOS LSI chips to
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...
was the basis for the first microprocessors, as engineers began recognizing that a complete
computer processor In computing and computer science, a processor or processing unit is an electrical component (digital circuit) that performs operations on an external data source, usually memory or some other data stream. It typically takes the form of a micropr ...
could be contained on several MOS LSI chips. Designers in the late 1960s were striving to integrate the
central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...
(CPU) functions of a computer onto a handful of MOS LSI chips, called microprocessor unit (MPU) chipsets. While there is disagreement over who invented the microprocessor, the first commercially produced microprocessor was the
Intel 4004 The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs. The 4004 was the first significa ...
, released as a single MOS LSI chip in 1971. The single-chip microprocessor was made possible with the development of MOS
silicon-gate In Semiconductor device fabrication, semiconductor electronics fabrication technology, a self-aligned gate is a transistor manufacturing approach whereby the gate (transistor), gate electrode of a MOSFET (metal–oxide–semiconductor field-effec ...
technology (SGT). The earliest MOS transistors had
aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
metal gate A metal gate, in the context of a lateral metal–oxide–semiconductor (MOS) stack, is the gate electrode separated by an oxide from the transistor's channel – the gate material is made from a metal. In most MOS transistors since about the mid ...
s, which Italian physicist
Federico Faggin Federico Faggin (, ; born 1 December 1941) is an Italian physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group d ...
replaced with
silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
self-aligned gate In semiconductor electronics fabrication technology, a self-aligned gate is a transistor manufacturing approach whereby the gate electrode of a MOSFET (metal–oxide–semiconductor field-effect transistor) is used as a mask for the doping of ...
s to develop the first silicon-gate MOS chip at Fairchild Semiconductor in 1968. Faggin later joined
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
and used his silicon-gate MOS technology to develop the 4004, along with
Marcian Hoff Marcian Edward "Ted" Hoff Jr. (born October 28, 1937 in Rochester, New York) is one of the inventors of the microprocessor. Education and work history Hoff received a bachelor's degree in electrical engineering from the Rensselaer Polytechnic Inst ...
, Stanley Mazor and
Masatoshi Shima is a Japanese electronics engineer. He was one of the architects of the world's first microprocessor, the Intel 4004. In 1968, Shima worked for Busicom in Japan, and did the logic design for a specialized CPU to be translated into three-chip c ...
in 1971. The 4004 was designed for Busicom, which had earlier proposed a multi-chip design in 1969, before Faggin's team at Intel changed it into a new single-chip design. Intel introduced the first commercial microprocessor, the
4-bit In computer architecture, 4-bit integers, or other data units are those that are 4 bits wide. Also, 4-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, or data buses of that si ...
Intel 4004, in 1971. It was soon followed by the 8-bit microprocessor
Intel 8008 The Intel 8008 ("''eight-thousand-eight''" or "''eighty-oh-eight''") is an early byte-oriented microprocessor designed by Computer Terminal Corporation (CTC), implemented and manufactured by Intel, and introduced in April 1972. It is an 8-bit CP ...
in 1972. Other embedded uses of 4-bit and 8-bit microprocessors, such as
terminal Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output dev ...
s,
printer Printer may refer to: Technology * Printer (publishing), a person or a company * Printer (computing), a hardware device * Optical printer for motion picture films People * Nariman Printer (fl. c. 1940), Indian journalist and activist * James ...
s, various kinds of
automation Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...
etc., followed soon after. Affordable 8-bit microprocessors with 16-bit addressing also led to the first general-purpose microcomputers from the mid-1970s on. The first use of the term "microprocessor" is attributed to Viatron Computer Systems describing the custom integrated circuit used in their System 21 small computer system announced in 1968. Since the early 1970s, the increase in capacity of microprocessors has followed Moore's law; this originally suggested that the number of components that can be fitted onto a chip doubles every year. With present technology, it is actually every two years, and as a result Moore later changed the period to two years.


First projects

These projects delivered a microprocessor at about the same time:
Garrett AiResearch Garrett AiResearch was a manufacturer of turboprop engines and turbochargers, and a pioneer in numerous aerospace technologies. It was previously known as Aircraft Tool and Supply Company, Garrett Supply Company, AiResearch Manufacturing Compa ...
's
Central Air Data Computer An air data computer (ADC) or central air data computer (CADC) computes altitude, vertical speed, air speed, and Mach number from pressure and temperature inputs. It is an essential avionics component found in modern aircraft. This computer, rath ...
(CADC) (1970),
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
' TMS 1802NC (September 1971) and
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
's 4004 (November 1971, based on an earlier 1969 Busicom design). Arguably,
Four-Phase Systems AL1 Four-Phase Systems was a computer company, founded by Lee Boysel and others, which built one of the earliest computers using semiconductor main memory and metal-oxide-semiconductor, MOS large-scale integration, LSI logic. The company was incorpo ...
microprocessor was also delivered in 1969.


Four-Phase Systems AL1 (1969)

The
Four-Phase Systems AL1 Four-Phase Systems was a computer company, founded by Lee Boysel and others, which built one of the earliest computers using semiconductor main memory and metal-oxide-semiconductor, MOS large-scale integration, LSI logic. The company was incorpo ...
was an 8-bit
bit slice Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary ''n''-bit central processing unit (CPU). Each of these co ...
chip containing eight registers and an ALU. It was designed by Lee Boysel in 1969. At the time, it formed part of a nine-chip, 24-bit CPU with three AL1s. It was later called a microprocessor when, in response to 1990s litigation by
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
, Boysel constructed a demonstration system where a single AL1 formed part of a courtroom demonstration computer system, together with RAM, ROM, and an input-output device.


Garrett AiResearch CADC (1970)

In 1968,
Garrett AiResearch Garrett AiResearch was a manufacturer of turboprop engines and turbochargers, and a pioneer in numerous aerospace technologies. It was previously known as Aircraft Tool and Supply Company, Garrett Supply Company, AiResearch Manufacturing Compa ...
(who employed designers
Ray Holt Raymond M. Holt is a computer designer and businessman in Silicon Valley. From 1968 to 1970, Ray and his brother Bill Holt were on the Garrett AiResearch's small design team that developed the world's first microprocessor chip set, the 20-bit ...
and Steve Geller) was invited to produce a digital computer to compete with
electromechanical In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
systems then under development for the main flight control computer in the
US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
's new
F-14 Tomcat The Grumman F-14 Tomcat is an American carrier-capable supersonic, twin-engine, two-seat, twin-tail, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental (VFX) program after the ...
fighter. The design was complete by 1970, and used a
MOS MOS or Mos may refer to: Technology * MOSFET (metal–oxide–semiconductor field-effect transistor), also known as the MOS transistor * Mathematical Optimization Society * Model output statistics, a weather-forecasting technique * MOS (filmm ...
-based chipset as the core CPU. The design was significantly (approximately 20 times) smaller and much more reliable than the mechanical systems it competed against and was used in all of the early Tomcat models. This system contained "a 20-bit, pipelined,
parallel Parallel is a geometric term of location which may refer to: Computing * Parallel algorithm * Parallel computing * Parallel metaheuristic * Parallel (software), a UNIX utility for running programs in parallel * Parallel Sysplex, a cluster of ...
multi-microprocessor". The Navy refused to allow publication of the design until 1997. Released in 1998, the documentation on the CADC, and the
MP944 The F-14's Central Air Data Computer, also abbreviated as CADC, computes altitude, vertical speed, air speed, and mach number from sensor inputs such as Pitot-static_system#Pitot_pressure, pitot and Pitot-static_system#Static_pressure, static press ...
chipset, are well known. Ray Holt's autobiographical story of this design and development is presented in the book: The Accidental Engineer.
Ray Holt Raymond M. Holt is a computer designer and businessman in Silicon Valley. From 1968 to 1970, Ray and his brother Bill Holt were on the Garrett AiResearch's small design team that developed the world's first microprocessor chip set, the 20-bit ...
graduated from California Polytechnic University in 1968, and began his computer design career with the CADC. From its inception, it was shrouded in secrecy until 1998 when at Holt's request, the US Navy allowed the documents into the public domain. Holt has claimed that no one has compared this microprocessor with those that came later. According to Parab et al. (2007), This convergence of DSP and microcontroller architectures is known as a
digital signal controller A digital signal controller (DSC) is a hybrid of microcontrollers and digital signal processors (DSPs). Like microcontrollers, DSCs have fast interrupt responses, offer control-oriented peripherals like PWMs and watchdog timers, and are usually ...
.


Gilbert Hyatt (1970)

In 1990, American engineer Gilbert Hyatt was awarded U.S. Patent No. 4,942,516, which was based on a 16-bit serial computer he built at his
Northridge, California Northridge is a neighborhood in the San Fernando Valley region of the Los Angeles, California, City of Los Angeles. The community is home to California State University, Northridge, and the Northridge Fashion Center. Originally named List_of_mino ...
home in 1969 from boards of bipolar chips after quitting his job at
Teledyne Teledyne Technologies Incorporated is an American industrial conglomerate. It was founded in 1960, as Teledyne, Inc., by Henry Singleton and George Kozmetsky. From August 1996 to November 1999, Teledyne existed as part of the conglomerate All ...
in 1968; though the patent had been submitted in December 1970 and prior to
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
' filings for the TMX 1795 and TMS 0100, Hyatt's invention was never manufactured. This nonetheless led to claims that Hyatt was the inventor of the microprocessor and the payment of substantial royalties through a Philips N.V. subsidiary, until Texas Instruments prevailed in a complex legal battle in 1996, when the U.S. Patent Office overturned key parts of the patent, while allowing Hyatt to keep it. Hyatt said in a 1990 ''Los Angeles Times'' article that his invention would have been created had his prospective investors backed him, and that the venture investors leaked details of his chip to the industry, though he did not elaborate with evidence to support this claim. In the same article, ''The Chip'' author
T.R. Reid T. R. Reid (born Thomas Roy Reid III in 1944) is an American reporter, documentary film correspondent, and author. He has also been a frequent guest on National Public Radio (NPR)'s ''Morning Edition''. Reid currently lives in Denver, Colorado. ...
was quoted as saying that historians may ultimately place Hyatt as a co-inventor of the microprocessor, in the way that Intel's Noyce and TI's Kilby share credit for the invention of the chip in 1958: "Kilby got the idea first, but Noyce made it practical. The legal ruling finally favored Noyce, but they are considered co-inventors. The same could happen here." Hyatt would go on to fight a decades-long legal battle with the state of California over alleged unpaid taxes on his patent's windfall after 1990, which would culminate in a landmark Supreme Court case addressing states'
sovereign immunity Sovereign immunity, or crown immunity, is a legal doctrine whereby a sovereign or state cannot commit a legal wrong and is immune from civil suit or criminal prosecution, strictly speaking in modern texts in its own courts. A similar, stronger ...
in ''
Franchise Tax Board of California v. Hyatt (2019) ''Franchise Tax Board of California v. Hyatt'' (short: ''Franchise Tax Bd. of Cal. v. Hyatt'' or ''Hyatt III''), 587 U.S. ___ (2019), was a United States Supreme Court case that determined that unless they consent, states have sovereign immunit ...
''.


Texas Instruments TMX 1795 (1970-1971)

Along with Intel (who developed the
8008 The Intel 8008 ("''eight-thousand-eight''" or "''eighty-oh-eight''") is an early byte-oriented microprocessor designed by Computer Terminal Corporation (CTC), implemented and manufactured by Intel, and introduced in April 1972. It is an 8-bit ...
), Texas Instruments developed in 1970–1971 a one-chip CPU replacement for the
Datapoint 2200 The Datapoint 2200 was a mass-produced programmable computer terminal usable as a computer, designed by Computer Terminal Corporation (CTC) founders Phil Ray and Gus Roche and announced by CTC in June 1970 (with units shipping in 1971). It was ...
terminal, the TMX 1795 (later TMC 1795.) Like the 8008, it was rejected by customer Datapoint. According to Gary Boone, the TMX 1795 never reached production. Since it was built to the same specification, its instruction set was very similar to the Intel 8008.


Texas Instruments TMS 1802NC (1971)

The TMS1802NC was announced September 17, 1971, and implemented a four-function calculator. The TMS1802NC, despite its designation, was not part of the
TMS 1000 The TMS1000 is a family of microcontrollers introduced by Texas Instruments in 1974. It combined a 4-bit central processor unit, read-only memory (ROM), random access memory (RAM), and input/output (I/O) lines as a complete "computer on a chip". ...
series; it was later redesignated as part of the TMS 0100 series, which was used in the TI Datamath calculator. Although marketed as a calculator-on-a-chip, the TMS1802NC was fully programmable, including on the chip a CPU with an 11-bit instruction word, 3520 bits (320 instructions) of ROM and 182 bits of RAM.


Pico/General Instrument (1971)

In 1971, Pico Electronics and
General Instrument General Instrument (GI) was an American electronics manufacturer based in Horsham, Pennsylvania, specializing in semiconductors and cable television equipment. They formed in New York City in 1923 as an electronics manufacturer. During the 1950s, ...
(GI) introduced their first collaboration in ICs, a complete single-chip calculator IC for the Monroe/ Litton Royal Digital III calculator. This chip could also arguably lay claim to be one of the first microprocessors or microcontrollers having
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...
,
RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...
and a RISC instruction set on-chip. The layout for the four layers of the PMOS process was hand drawn at x500 scale on mylar film, a significant task at the time given the complexity of the chip. Pico was a spinout by five GI design engineers whose vision was to create single-chip calculator ICs. They had significant previous design experience on multiple calculator chipsets with both GI and Marconi-Elliott. The key team members had originally been tasked by
Elliott Automation Elliott Brothers (London) Ltd was an early computer company of the 1950s–60s in the United Kingdom. It traced its descent from a firm of instrument makers founded by William Elliott (instrument maker), William Elliott (1780 or 1781-1853) in ...
to create an 8-bit computer in MOS and had helped establish a MOS Research Laboratory in
Glenrothes Glenrothes (; , ; sco, Glenrothes; gd, Gleann Rathais) is a town situated in the heart of Fife, in east-central Scotland. It is about north of Edinburgh and south of Dundee. The town had a population of 39,277 in the 2011 census, making i ...
, Scotland in 1967. Calculators were becoming the largest single market for semiconductors so Pico and GI went on to have significant success in this burgeoning market. GI continued to innovate in microprocessors and microcontrollers with products including the CP1600, IOB1680 and PIC1650. In 1987, the GI Microelectronics business was spun out into the
Microchip An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
PIC microcontroller PIC (usually pronounced as ''"pick"'') is a family of microcontrollers made by Microchip Technology, derived from the PIC1650"PICmicro Family Tree", PIC16F Seminar Presentation originally developed by General Instrument's Microelectronics ...
business.


Intel 4004 (1971)

The
Intel 4004 The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs. The 4004 was the first significa ...
is often (falsely) regarded as the first true microprocessor built on a single chip, priced at . The claim of being the first is definetely false, as the earlier TMS1802NC was also a true microprocessor built on a single chip. The first known advertisement for the 4004 is dated November 15, 1971 and appeared in ''
Electronic News ''Electronic News'' was a publication that covered the electronics industry, from semiconductor equipment and materials to military/aerospace electronics to supercomputers. It was originally a weekly trade newspaper, which covered all aspects of ...
''. The microprocessor was designed by a team consisting of Italian engineer
Federico Faggin Federico Faggin (, ; born 1 December 1941) is an Italian physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group d ...
, American engineers
Marcian Hoff Marcian Edward "Ted" Hoff Jr. (born October 28, 1937 in Rochester, New York) is one of the inventors of the microprocessor. Education and work history Hoff received a bachelor's degree in electrical engineering from the Rensselaer Polytechnic Inst ...
and Stanley Mazor, and Japanese engineer
Masatoshi Shima is a Japanese electronics engineer. He was one of the architects of the world's first microprocessor, the Intel 4004. In 1968, Shima worked for Busicom in Japan, and did the logic design for a specialized CPU to be translated into three-chip c ...
. The project that produced the 4004 originated in 1969, when Busicom, a Japanese calculator manufacturer, asked Intel to build a chipset for high-performance
desktop calculator An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. The first solid-state electronic calculator was created in the early 1960s. Pocket-siz ...
s. Busicom's original design called for a programmable chip set consisting of seven different chips. Three of the chips were to make a special-purpose CPU with its program stored in ROM and its data stored in shift register read-write memory.
Ted Hoff Marcian Edward "Ted" Hoff Jr. (born October 28, 1937 in Rochester, New York) is one of the inventors of the microprocessor. Education and work history Hoff received a bachelor's degree in electrical engineering from the Rensselaer Polytechnic Inst ...
, the Intel engineer assigned to evaluate the project, believed the Busicom design could be simplified by using dynamic RAM storage for data, rather than shift register memory, and a more traditional general-purpose CPU architecture. Hoff came up with a four-chip architectural proposal: a ROM chip for storing the programs, a dynamic RAM chip for storing data, a simple I/O device, and a 4-bit central processing unit (CPU). Although not a chip designer, he felt the CPU could be integrated into a single chip, but as he lacked the technical know-how the idea remained just a wish for the time being. While the architecture and specifications of the MCS-4 came from the interaction of Hoff with Stanley Mazor, a software engineer reporting to him, and with Busicom engineer
Masatoshi Shima is a Japanese electronics engineer. He was one of the architects of the world's first microprocessor, the Intel 4004. In 1968, Shima worked for Busicom in Japan, and did the logic design for a specialized CPU to be translated into three-chip c ...
, during 1969, Mazor and Hoff moved on to other projects. In April 1970, Intel hired Italian engineer
Federico Faggin Federico Faggin (, ; born 1 December 1941) is an Italian physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group d ...
as project leader, a move that ultimately made the single-chip CPU final design a reality (Shima meanwhile designed the Busicom calculator firmware and assisted Faggin during the first six months of the implementation). Faggin, who originally developed the
silicon gate In semiconductor electronics fabrication technology, a self-aligned gate is a transistor manufacturing approach whereby the gate electrode of a MOSFET (metal–oxide–semiconductor field-effect transistor) is used as a mask for the doping of th ...
technology (SGT) in 1968 at Fairchild Semiconductor and designed the world's first commercial integrated circuit using SGT, the Fairchild 3708, had the correct background to lead the project into what would become the first commercial general purpose microprocessor. Since SGT was his very own invention, Faggin also used it to create his new methodology for
random logic Random logic is a semiconductor circuit design technique that translates high-level logic descriptions directly into hardware features such as AND and OR gates. The name derives from the fact that few easily discernible patterns are evident in the a ...
design that made it possible to implement a single-chip CPU with the proper speed, power dissipation and cost. The manager of Intel's MOS Design Department was Leslie L. Vadász at the time of the MCS-4 development but Vadász's attention was completely focused on the mainstream business of semiconductor memories so he left the leadership and the management of the MCS-4 project to Faggin, who was ultimately responsible for leading the 4004 project to its realization. Production units of the 4004 were first delivered to Busicom in March 1971 and shipped to other customers in late 1971.


8-bit designs

The
Intel 4004 The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs. The 4004 was the first significa ...
was followed in 1972 by the
Intel 8008 The Intel 8008 ("''eight-thousand-eight''" or "''eighty-oh-eight''") is an early byte-oriented microprocessor designed by Computer Terminal Corporation (CTC), implemented and manufactured by Intel, and introduced in April 1972. It is an 8-bit CP ...
, the world's first 8-bit microprocessor. The 8008 was not, however, an extension of the 4004 design, but instead the culmination of a separate design project at Intel, arising from a contract with Computer Terminals Corporation, of San Antonio TX, for a chip for a terminal they were designing, the
Datapoint 2200 The Datapoint 2200 was a mass-produced programmable computer terminal usable as a computer, designed by Computer Terminal Corporation (CTC) founders Phil Ray and Gus Roche and announced by CTC in June 1970 (with units shipping in 1971). It was ...
—fundamental aspects of the design came not from Intel but from CTC. In 1968, CTC's Vic Poor and Harry Pyle developed the original design for the instruction set and operation of the processor. In 1969, CTC contracted two companies,
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
and
Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
, to make a single-chip implementation, known as the CTC 1201. In late 1970 or early 1971, TI dropped out being unable to make a reliable part. In 1970, with Intel yet to deliver the part, CTC opted to use their own implementation in the Datapoint 2200, using traditional TTL logic instead (thus the first machine to run "8008 code" was not in fact a microprocessor at all and was delivered a year earlier). Intel's version of the 1201 microprocessor arrived in late 1971, but was too late, slow, and required a number of additional support chips. CTC had no interest in using it. CTC had originally contracted Intel for the chip, and would have owed them for their design work. To avoid paying for a chip they did not want (and could not use), CTC released Intel from their contract and allowed them free use of the design. Intel marketed it as the 8008 in April, 1972, as the world's first 8-bit microprocessor. It was the basis for the famous "
Mark-8 The Mark-8 is a microcomputer design from 1974, based on the Intel 8008 CPU (which was the world's first 8-bit microprocessor). The Mark-8 was designed by Jonathan Titus, a Virginia Tech graduate student in Chemistry. After building the machine ...
" computer kit advertised in the magazine ''
Radio-Electronics ''Radio-Electronics'' was an American electronics magazine that was published under various titles from 1929 to 2003. Hugo Gernsback, sometimes called the father of science fiction, started it as ''Radio-Craft'' in July 1929. The title was changed ...
'' in 1974. This processor had an 8-bit data bus and a 14-bit address bus. The 8008 was the precursor to the successful
Intel 8080 The Intel 8080 (''"eighty-eighty"'') is the second 8-bit microprocessor designed and manufactured by Intel. It first appeared in April 1974 and is an extended and enhanced variant of the earlier 8008 design, although without binary compatibil ...
(1974), which offered improved performance over the 8008 and required fewer support chips. Federico Faggin conceived and designed it using high voltage N channel MOS. The
Zilog Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...
(1976) was also a Faggin design, using low voltage N channel with depletion load and derivative Intel 8-bit processors: all designed with the methodology Faggin created for the 4004.
Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorol ...
released the competing 6800 in August 1974, and the similar
MOS Technology 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...
was released in 1975 (both designed largely by the same people). The 6502 family rivaled the Z80 in popularity during the 1980s. A low overall cost, little packaging, simple computer bus requirements, and sometimes the integration of extra circuitry (e.g. the Z80's built-in
memory refresh 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 without modification, for the purpose of preserving the information."refresh cycle" i ...
circuitry) allowed the home computer "revolution" to accelerate sharply in the early 1980s. This delivered such inexpensive machines as the Sinclair
ZX81 The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cos ...
, which sold for . A variation of the 6502, the
MOS Technology 6510 300px, Image of the internals of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). The chip on the right is the 6581 SID. The production week/year (WWYY) of each chip is given below its name. The MOS Technology 6510 is an 8-bit mic ...
was used in the
Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...
and yet another variant, the 8502, powered the
Commodore 128 The Commodore 128, also known as the C128, C-128, C= 128,The "C=" represents the graphical part of the logo. is the last 8-bit home computer that was commercially released by Commodore Business Machines (CBM). Introduced in January 1985 at the ...
. The Western Design Center, Inc (WDC) introduced the CMOS
WDC 65C02 The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502. The 65C02 fixed several problems in the original 6502 and added some new instructions, but its main feature wa ...
in 1982 and licensed the design to several firms. It was used as the CPU in the
Apple IIe The Apple IIe (styled as Apple //e) is the third model in the Apple II series of personal computers produced by Apple Computer. The ''e'' in the name stands for ''enhanced'', referring to the fact that several popular features were now built-in ...
and IIc personal computers as well as in medical implantable grade pacemakers and
defibrillator Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''coun ...
s, automotive, industrial and consumer devices. WDC pioneered the licensing of microprocessor designs, later followed by
ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...
(32-bit) and other microprocessor
intellectual property Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, cop ...
(IP) providers in the 1990s. Motorola introduced the MC6809 in 1978. It was an ambitious and well thought-through 8-bit design that was source compatible with the 6800, and implemented using purely hard-wired logic (subsequent 16-bit microprocessors typically used microcode to some extent, as CISC design requirements were becoming too complex for pure hard-wired logic). Another early 8-bit microprocessor was the
Signetics 2650 The Signetics 2650 was an 8-bit microprocessor introduced in July 1975. According to Adam Osborne's book ''An Introduction to Microprocessors Vol 2: Some Real Products'', it was "the most minicomputer-like" of the microprocessors available at ...
, which enjoyed a brief surge of interest due to its innovative and powerful instruction set architecture. A seminal microprocessor in the world of spaceflight was
RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
's
RCA 1802 The COSMAC (Complementary Symmetry Monolithic Array Computer) is an 8-bit microprocessor family introduced by RCA. It is historically notable as the first CMOS microprocessor. The first production model was the two-chip CDP1801R and CDP1801U, wh ...
(aka CDP1802, RCA COSMAC) (introduced in 1976), which was used on board the '' Galileo'' probe to Jupiter (launched 1989, arrived 1995). RCA COSMAC was the first to implement CMOS technology. The CDP1802 was used because it could be run at very low power, and because a variant was available fabricated using a special production process,
silicon on sapphire Silicon on sapphire (SOS) is a hetero-epitaxial process for metal-oxide-semiconductor (MOS) integrated circuit (IC) manufacturing that consists of a thin layer (typically thinner than 0.6 µm) of silicon grown on a sapphire (Al2O3) wafer. ...
(SOS), which provided much better protection against cosmic radiation and electrostatic discharge than that of any other processor of the era. Thus, the SOS version of the 1802 was said to be the first
radiation-hardened Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation ( particle radiation and high-energy electromagnetic radiation), especially for environ ...
microprocessor. The RCA 1802 had a static design, meaning that the
clock frequency In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pr ...
could be made arbitrarily low, or even stopped. This let the ''Galileo'' spacecraft use minimum electric power for long uneventful stretches of a voyage. Timers or sensors would awaken the processor in time for important tasks, such as navigation updates, attitude control, data acquisition, and radio communication. Current versions of the Western Design Center 65C02 and 65C816 also have
static core Static core generally refers to a microprocessor (MPU) entirely implemented in static logic.  A static core MPU may be halted by stopping the system clock oscillator that is driving it, maintaining its state and resume processing at the poin ...
s, and thus retain data even when the clock is completely halted.


12-bit designs

The
Intersil 6100 The Intersil 6100 is a single-chip microprocessor implementation of the 12-bit PDP-8 instruction set, along with a range of peripheral support and memory ICs developed by Intersil in the mid-1970s. It was sometimes referred to as the CMOS-PDP8 ...
family consisted of a 12-bit microprocessor (the 6100) and a range of peripheral support and memory ICs. The microprocessor recognised the DEC
PDP-8 The PDP-8 is a 12-bit computing, 12-bit minicomputer that was produced by Digital Equipment Corporation, Digital Equipment Corporation (DEC). It was the first commercially successful minicomputer, with over 50,000 units being sold over the model's ...
minicomputer instruction set. As such it was sometimes referred to as the CMOS-PDP8. Since it was also produced by Harris Corporation, it was also known as the Harris HM-6100. By virtue of its CMOS technology and associated benefits, the 6100 was being incorporated into some military designs until the early 1980s.


16-bit designs

The first multi-chip 16-bit microprocessor was the
National Semiconductor National Semiconductor was an American semiconductor manufacturer which specialized in analog devices and subsystems, formerly with headquarters in Santa Clara, California. The company produced power management integrated circuits, display dr ...
IMP-16 The IMP-16, by National Semiconductor, was the first multi-chip 16-bit microprocessor, released in 1973. It consisted of five PMOS integrated circuits: four identical RALU chips, short for register and ALU, providing the data path, and one CROM ...
, introduced in early 1973. An 8-bit version of the chipset was introduced in 1974 as the IMP-8. Other early multi-chip 16-bit microprocessors include the
MCP-1600 The MCP-1600 is a multi-chip 16-bit microprocessor introduced by Western Digital in 1975 and produced through the early 1980s. Used in the Pascal MicroEngine, the WD16 processor in the Alpha Microsystems AM-100, and the DEC LSI-11 microcomput ...
that Digital Equipment Corporation (DEC) used in the
LSI-11 The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...
OEM board set and the packaged PDP-11/03 minicomputer—and the Fairchild Semiconductor MicroFlame 9440, both introduced in 1975–76. In late 1974, National introduced the first 16-bit single-chip microprocessor, the
National Semiconductor PACE National Semiconductor's IPC-16A PACE, short for "Processing and Control Element", was the first commercial single-chip 16-bit microprocessor, announced in late 1974. It was a single-chip implementation of their early 1973 five-chip IMP-16 archit ...
, which was later followed by an NMOS version, the INS8900. Next in list is the
General Instrument CP1600 The CP1600 is a 16-bit microprocessor created in a partnership between General Instrument and Honeywell, introduced in February 1975. It is one of the first single-chip 16-bit processors. The overall design bore a strong resemblance to the PDP-11. ...
, released in February 1975, which was used mainly in the Intellivision console. Another early single-chip 16-bit microprocessor was TI's
TMS 9900 Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit microprocessors. It implemented Texas Instruments' TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end ...
, which was also compatible with their
TI-990 {{Short description, Series of 16-bit computers by Texas Instruments. The TI-990 was a series of 16-bit minicomputers sold by Texas Instruments (TI) in the 1970s and 1980s. The TI-990 was a replacement for TI's earlier minicomputer systems, the T ...
line of minicomputers. The 9900 was used in the TI 990/4 minicomputer, the
TI-99/4A The TI-99/4 and TI-99/4A are home computers released by Texas Instruments in 1979 and 1981, respectively. Based on the Texas Instruments TMS9900 microprocessor originally used in minicomputers, the TI-99/4 was the first 16-bit home computer. ...
home computer, and the TM990 line of OEM microcomputer boards. The chip was packaged in a large ceramic 64-pin Dual in-line package, DIP package, while most 8-bit microprocessors such as the Intel 8080 used the more common, smaller, and less expensive plastic 40-pin DIP. A follow-on chip, the TMS 9980, was designed to compete with the Intel 8080, had the full TI 990 16-bit instruction set, used a plastic 40-pin package, moved data 8 bits at a time, but could only address 16 Kilobyte, KB. A third chip, the TMS 9995, was a new design. The family later expanded to include the 99105 and 99110. The Western Design Center (WDC) introduced the CMOS WDC 65816/65802, 65816 16-bit upgrade of the WDC CMOS WDC 65C02, 65C02 in 1984. The 65816 16-bit microprocessor was the core of the Apple IIGS and later the Super Nintendo Entertainment System, making it one of the most popular 16-bit designs of all time. Intel "upsized" their 8080 design into the 16-bit Intel 8086, the first member of the x86 family, which powers most modern IBM PC compatible, PC type computers.
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
introduced the 8086 as a cost-effective way of porting software from the 8080 lines, and succeeded in winning much business on that premise. The Intel 8088, 8088, a version of the 8086 that used an 8-bit external data bus, was the microprocessor in the first IBM PC. Intel then released the Intel 80186, 80186 and Intel 80188, 80188, the Intel 80286, 80286 and, in 1985, the 32-bit Intel 80386, 80386, cementing their PC market dominance with the processor family's backwards compatibility. The 80186 and 80188 were essentially versions of the 8086 and 8088, enhanced with some onboard peripherals and a few new instructions. Although Intel's 80186 and 80188 were not used in IBM PC type designs, second source versions from NEC, the NEC V20, V20 and V30 frequently were. The 8086 and successors had an innovative but limited method of memory segmentation, while the 80286 introduced a full-featured segmented memory management unit (MMU). The 80386 introduced a flat 32-bit memory model with paged memory management. The 16-bit Intel x86 processors up to and including the 80386 do not include Floating-point unit, floating-point units (FPUs). Intel introduced the Intel 8087, 8087, Intel 80187, 80187, Intel 80287, 80287 and Intel 80387, 80387 math coprocessors to add hardware floating-point and transcendental function capabilities to the 8086 through 80386 CPUs. The 8087 works with the 8086/8088 and 80186/80188, the 80187 works with the 80186 but not the 80188, the 80287 works with the 80286 and the 80387 works with the 80386. The combination of an x86 CPU and an x87 coprocessor forms a single multi-chip microprocessor; the two chips are programmed as a unit using a single integrated instruction set. The 8087 and 80187 coprocessors are connected in parallel with the data and address buses of their parent processor and directly execute instructions intended for them. The 80287 and 80387 coprocessors are interfaced to the CPU through I/O ports in the CPU's address space, this is transparent to the program, which does not need to know about or access these I/O ports directly; the program accesses the coprocessor and its registers through normal instruction opcodes.


32-bit designs

16-bit designs had only been on the market briefly when 32-bit implementations started to appear. The most significant of the 32-bit designs is the Motorola 68000, Motorola MC68000, introduced in 1979. The 68k, as it was widely known, had 32-bit registers in its programming model but used 16-bit internal data paths, three 16-bit Arithmetic Logic Units, and a 16-bit external data bus (to reduce pin count), and externally supported only 24-bit addresses (internally it worked with full 32 bit addresses). In PC-based IBM-compatible mainframes the MC68000 internal microcode was modified to emulate the 32-bit System/370 IBM mainframe. Motorola generally described it as a 16-bit processor. The combination of high performance, large (16 megabytes or 224 bytes) memory space and fairly low cost made it the most popular CPU design of its class. The Apple Lisa and Apple Macintosh, Macintosh designs made use of the 68000, as did a host of other designs in the mid-1980s, including the Atari ST and Commodore Amiga. The world's first single-chip fully 32-bit microprocessor, with 32-bit data paths, 32-bit buses, and 32-bit addresses, was the AT&T Corporation, AT&T Bell Labs Bellmac 32, BELLMAC-32A, with first samples in 1980, and general production in 1982. After the Bell System divestiture, divestiture of AT&T in 1984, it was renamed the WE 32000 (WE for Western Electric), and had two follow-on generations, the WE 32100 and WE 32200. These microprocessors were used in the AT&T 3B5 and 3B15 minicomputers; in the 3B2, the world's first desktop super microcomputer; in the "Companion", the world's first 32-bit laptop computer; and in "Alexander", the world's first book-sized super microcomputer, featuring ROM-pack memory cartridges similar to today's gaming consoles. All these systems ran the UNIX System V operating system. The first commercial, single chip, fully 32-bit microprocessor available on the market was the HP FOCUS. Intel's first 32-bit microprocessor was the Intel iAPX 432, iAPX 432, which was introduced in 1981, but was not a commercial success. It had an advanced Capability-based security, capability-based Object (computer science), object-oriented architecture, but poor performance compared to contemporary architectures such as Intel's own 80286 (introduced 1982), which was almost four times as fast on typical benchmark tests. However, the results for the iAPX432 was partly due to a rushed and therefore suboptimal Ada (programming language), Ada compiler. Motorola's success with the 68000 led to the Motorola 68010, MC68010, which added virtual memory support. The Motorola 68020, MC68020, introduced in 1984 added full 32-bit data and address buses. The 68020 became hugely popular in the Unix supermicrocomputer market, and many small companies (e.g., Altos Computer Systems, Altos, UNOS (operating system), Charles River Data Systems, Cromemco) produced desktop-size systems. The Motorola 68030, MC68030 was introduced next, improving upon the previous design by integrating the MMU into the chip. The continued success led to the Motorola 68040, MC68040, which included an floating-point unit, FPU for better math performance. The 68050 failed to achieve its performance goals and was not released, and the follow-up Motorola 68060, MC68060 was released into a market saturated by much faster RISC designs. The 68k family faded from use in the early 1990s. Other large companies designed the 68020 and follow-ons into embedded equipment. At one point, there were more 68020s in embedded equipment than there were
Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...
Pentiums in PCs. The Motorola ColdFire, ColdFire processor cores are derivatives of the 68020. During this time (early to mid-1980s),
National Semiconductor National Semiconductor was an American semiconductor manufacturer which specialized in analog devices and subsystems, formerly with headquarters in Santa Clara, California. The company produced power management integrated circuits, display dr ...
introduced a very similar 16-bit pinout, 32-bit internal microprocessor called the NS 16032 (later renamed 32016), the full 32-bit version named the NS320xx, NS 32032. Later, National Semiconductor produced the NS320xx, NS 32132, which allowed two CPUs to reside on the same memory bus with built in arbitration. The NS32016/32 outperformed the MC68000/10, but the NS32332—which arrived at approximately the same time as the MC68020—did not have enough performance. The third generation chip, the NS32532, was different. It had about double the performance of the MC68030, which was released around the same time. The appearance of RISC processors like the AM29000 and MC88000 (now both dead) influenced the architecture of the final core, the NS32764. Technically advanced—with a superscalar RISC core, 64-bit bus, and internally overclocked—it could still execute Series 32000 instructions through real-time translation. When National Semiconductor decided to leave the Unix market, the chip was redesigned into the Swordfish Embedded processor with a set of on-chip peripherals. The chip turned out to be too expensive for the laser printer market and was killed. The design team went to Intel and there designed the Pentium processor, which is very similar to the NS32764 core internally. The big success of the Series 32000 was in the laser printer market, where the NS32CG16 with microcoded BitBlt instructions had very good price/performance and was adopted by large companies like Canon. By the mid-1980s, Sequent Computer Systems, Sequent introduced the first SMP server-class computer using the NS 32032. This was one of the design's few wins, and it disappeared in the late 1980s. The MIPS architecture, MIPS R2000 (microprocessor), R2000 (1984) and R3000 (1989) were highly successful 32-bit RISC microprocessors. They were used in high-end workstations and servers by Silicon Graphics, SGI, among others. Other designs included the Zilog Z80000, which arrived too late to market to stand a chance and disappeared quickly. The ARM architecture family, ARM first appeared in 1985. This is a RISC processor design, which has since come to dominate the 32-bit embedded systems processor space due in large part to its power efficiency, its licensing model, and its wide selection of system development tools. Semiconductor manufacturers generally license cores and integrate them into their own system on a chip products; only a few such vendors such as Apple are licensed to modify the ARM cores or create their own. Most cell phones include an ARM processor, as do a wide variety of other products. There are microcontroller-oriented ARM cores without virtual memory support, as well as symmetric multiprocessor system, symmetric multiprocessor (SMP) applications processors with virtual memory. From 1993 to 2003, the 32-bit x86 architectures became increasingly dominant in desktop computer, desktop, laptop, and server markets, and these microprocessors became faster and more capable. Intel had licensed early versions of the architecture to other companies, but declined to license the Pentium, so AMD and Cyrix built later versions of the architecture based on their own designs. During this span, these processors increased in complexity (transistor count) and capability (instructions/second) by at least three orders of magnitude. Intel's Pentium line is probably the most famous and recognizable 32-bit processor model, at least with the public at broad.


64-bit designs in personal computers

While
64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A compu ...
microprocessor designs have been in use in several markets since the early 1990s (including the Nintendo 64 gaming console in 1996), the early 2000s saw the introduction of 64-bit microprocessors targeted at the PC market. With AMD's introduction of a 64-bit architecture backwards-compatible with x86, x86-64 (also called AMD64), in September 2003, followed by Intel's near fully compatible 64-bit extensions (first called IA-32e or EM64T, later renamed Intel 64), the 64-bit desktop era began. Both versions can run 32-bit legacy applications without any performance penalty as well as new 64-bit software. With operating systems Windows XP Professional x64 Edition, Windows XP x64, Windows Vista x64, Windows 7 x64, Linux, BSD, and macOS that run 64-bit natively, the software is also geared to fully utilize the capabilities of such processors. The move to 64 bits is more than just an increase in register size from the IA-32 as it also doubles the number of general-purpose registers. The move to 64 bits by PowerPC had been intended since the architecture's design in the early 90s and was not a major cause of incompatibility. Existing integer registers are extended as are all related data pathways, but, as was the case with IA-32, both floating-point and vector units had been operating at or above 64 bits for several years. Unlike what happened when IA-32 was extended to x86-64, no new general purpose registers were added in 64-bit PowerPC, so any performance gained when using the 64-bit mode for applications making no use of the larger address space is minimal. In 2011, ARM introduced the new 64-bit ARM architecture.


RISC

In the mid-1980s to early 1990s, a crop of new high-performance reduced instruction set computer ( RISC) microprocessors appeared, influenced by discrete RISC-like CPU designs such as the IBM 801 and others. RISC microprocessors were initially used in special-purpose machines and Unix workstations, but then gained wide acceptance in other roles. The first commercial RISC microprocessor design was released in 1984, by MIPS Computer Systems, the 32-bit R2000 (microprocessor), R2000 (the R1000 was not released). In 1986, HP released its first system with a PA-RISC CPU. In 1987, in the non-Unix Acorn computers' 32-bit, then cache-less, ARM2-based Acorn Archimedes became the first commercial success using the ARM architecture family, ARM architecture, then known as Acorn RISC Machine (ARM); first silicon ARM1 in 1985. The R3000 made the design truly practical, and the R4000 introduced the world's first commercially available 64-bit RISC microprocessor. Competing projects would result in the IBM IBM POWER Instruction Set Architecture, POWER and Sun Microsystems, Sun SPARC architectures. Soon every major vendor was releasing a RISC design, including the AT&T CRISP, AMD 29000, Intel i860 and Intel i960, Motorola 88000, DEC Alpha. In the late 1990s, only two 64-bit RISC architectures were still produced in volume for non-embedded applications: SPARC and Power ISA, but as ARM has become increasingly powerful, in the early 2010s, it became the third RISC architecture in the general computing segment.


SMP and multi-core design

SMP ''symmetric multiprocessing'' is a configuration of two, four, or more CPU's (in pairs) that are typically used in servers, certain workstations and in desktop personal computers, since the 1990s. A multi-core processor is a single CPU that contains more than one microprocessor core. This popular two-socket motherboard from ABIT BP6, Abit was released in 1999 as the first SMP enabled PC motherboard, the Pentium Pro, Intel Pentium Pro was the first commercial CPU offered to system builders and enthusiasts. The Abit BP9 supports two Intel Celeron CPU's and when used with a SMP enabled operating system (Windows NT/2000/Linux) many applications obtain much higher performance than a single CPU. The early Celerons are easily overclockable and hobbyists used these relatively inexpensive CPU's clocked as high as 533Mhz - far beyond Intel's specification. After discovering the capacity of these motherboards Intel removed access to the multiplier in later CPU's. In 2001 IBM released the POWER4 CPU, it was a processor that was developed over five years of research, began in 1996 using a team of 250 researchers. The effort to accomplish the impossible was buttressed by development of and through—remote-collaboration and assigning younger engineers to work with more experienced engineers. The teams work achieved success with the new microprocessor, Power4. It is a two-in-one CPU that more than doubled performance at half the price of the competition, and a major advance in computing. The business magazine ''eWeek'' wrote: ''“The newly designed 1GHz Power4 represents a tremendous leap over its predecessor”''. An industry analyst, Brad Day of Giga Information Group said: ''“IBM is getting very aggressive, and this server is a game changer”.'' The Power4 won "''Analysts’ Choice Award for Best Workstation/Server Processor of 2001", and'' it broke notable records, including winning a contest against the best players on the Jeopardy! U.S. television show. Intel's Yonah (microprocessor), codename Yonah CPU's launched on Jan 6, 2006 and were manufactured with two dies packaged on a multi-chip module. In a hotly-contested marketplace List of AMD processors, AMD and others released new versions of multi-core CPU's, AMD's SMP enabled Athlon MP CPU's from the Athlon-XP, AthlonXP line in 2001, Sun released the UltraSPARC T1, Niagara and UltraSPARC T2, Niagara 2 with eight-cores, AMD's Athlon 64 X2, Athlon X2 was released in June 2007. The companies were engaged in a never-ending race for speed, indeed more demanding software mandated more processing power and faster CPU speeds. By 2012 ''dual and quad-core'' processors became widely used in PCs and laptops, newer processors - similar to the higher cost professional level Intel Xeon's - with additional cores that execute instructions in parallel so software performance typically increases, provided the software is designed to utilize advanced hardware. Operating systems provided support for multiple-cores and SMD CPU's, many software applications including large workload and resource intensive applications - such as 3-D games - are programmed to take advantage of multiple core and multi-CPU systems. Apple, Intel, and AMD currently lead the market with multiple core desktop and workstation CPU's. Although they frequently hip-hop each other for the lead in the performance tier. Intel retains higher frequencies and thus has the fastest single core performance, while AMD is often the leader in multi-threaded routines due to a more advanced ISA and the process node the CPU's are fabricated on. Multiprocessing concepts for multi-core/multi-cpu configurations are related to Amdahl's law.


Market statistics

In 1997, about 55% of all central processing unit, CPUs sold in the world were 8-bit microcontrollers, of which over 2 billion were sold. In 2002, less than 10% of all the CPUs sold in the world were 32-bit or more. Of all the 32-bit CPUs sold, about 2% are used in desktop or laptop personal computers. Most microprocessors are used in embedded control applications such as household appliances, automobiles, and computer peripherals. Taken as a whole, the average price for a microprocessor, microcontroller, or digital signal processor, DSP is just over . In 2003, about $44 billion (equivalent to about $ billion in ) worth of microprocessors were manufactured and sold. Although about half of that money was spent on CPUs used in desktop or laptop
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s, those count for only about 2% of all CPUs sold. The quality-adjusted price of laptop microprocessors improved −25% to −35% per year in 2004–2010, and the rate of improvement slowed to −15% to −25% per year in 2010–2013. About 10 billion CPUs were manufactured in 2008. Most new CPUs produced each year are embedded.


See also

* Comparison of instruction set architectures * Computer architecture * Computer engineering * List of microprocessors * Microarchitecture * Microprocessor chronology


Notes


References

*


External links


Patent problems
* * * * * * * * {{Authority control Microprocessors, American inventions Japanese inventions Digital electronics History of computing hardware Microcomputers Telecommunications engineering 1971 introductions