Processors (CPU)

What is Microprocessor? Design, Types, Pros, Cons & More

July 15, 2022

In This Article

What is Microprocessor?

A microprocessor refers to the processor or CPU that comes with millions of small transistors, registers, accumulator, and diodes.

It also contains the ALU and a control unit that controls the flow of data and performs the arithmetical and logical operations respectively.

In simple words, a microprocessor is the logic chip mounted on a single Integrated Circuit which forms the central unit of the computer system.

KEY TAKEAWAYS

A microprocessor is classified on the basis of the number of instructions processed, the size, clock speed and the number of bits used.
It comes with advanced architectural design to perform vital tasks such as addition, subtraction, logical operations, inter-processing, I/O management, and device communication.
These microprocessors follow a simple principle of fetch, decode and execute while operating.
There is a primary and secondary memory in the microprocessors that come in different types such as CISC and RISC, EPIC and Superscalar, and more.

Understanding Microprocessor

In a computer, the central unit is the microprocessor. This actually refers to the single IC or Integrated Circuit on which the CPU is built.

Factors for Classification

The classification of the microprocessors is usually done on the basis of a few specific factors such as:

The number of instructions they are able to process in a given period of time
Their size
Their respective clock speed which is usually measured in Megahertz and denoted as MHz and
The number of bits used in each instruction.

Tasks Performed

A microprocessor is mainly built on a silicon microchip and is more advanced in architectural design which helps it to perform several tasks which includes and are not limited to:

Addition and subtraction
Inter-processing
Device communication
Input and output management and more.

Working Process

The working process of the microprocessors typically follows three specific steps. These are:

Fetch – This process involves searching the information that is usually stored in the storage.
Decode – This process involves understating the instruction so that it can be assigned further. The ALU also registers the data in the interim at this stage.
Execute – This is the process that involves carrying out the instructions as received and assigned, and to send it in binary form to the output port.

Generations

The microprocessor has come a long way and has evolved significantly.

Their evolution also helps in categorizing them into different groups. Here is the brief history of their evolution.

First Generation:

The microprocessors of this era are usually called the 4-bit microprocessors.

The first generation of microprocessors came into existence in 1971-1972 and was introduced by Stanley Mazor & Ted Hoff forIntel Corporation. Since these were 4-bit microprocessors, these were named Intel 4004 or Intel 4040.

These were processors on a single chip and could perform tasks including simple arithmetic and logical operations like addition, subtraction, Boolean OR and Boolean AND with a clock speed of 740 KHz.

There were about 2300 transistors, 16 pins, and could process 60K instructions per second.

Second Generation:

The second generation microprocessors were called the 8-bit microprocessors and were introduced by Intel in 1972-1973.

These processors could perform arithmetic and logical operations in 8-bit words and therefore were called Intel 8008.

The 8008 could handle 50K instructions per second at a clock speed of 500 KHz.

The other versions were more improved and introduced as 8080, 8085 and more.

The 8080, introduced in 1974 came with a clock speed of 2 MHz and could handle 60K instructions per second.

The transistors of this transistor literally performed at a speed which was 10 times higher in comparison to that of Intel 8008.

The 8085 microprocessor, on the other hand, was introduced in 1976 and came with 6500 transistors, a clock speed of 3 MHz, 40 pins, and could handle 769230 instructions per second.

Third Generation:

Referred to as 16-bit microprocessors, Intel introduced them in 1978 as Intel 8086, Zilog Z800 and 80286.

These microprocessors could perform just like a minicomputer with a clock speed varying between 4 MHz and 10 MHz usually of the 29000 transistors that could handle 2.5 million instructions per second using just 40 pins.

Further, in 1982, 80186 and 80188 microprocessors were invented that came with a clock speed of 6 MHz.

The 80286 microprocessor also came into existence after that with a clock speed of 8 MHz, 134000 transistors, 68 pins and could handle as many as 4 million instructions per second.

Fourth Generation:

The 4^th generation microprocessors are called 32-bit microprocessors and there were several companies that produced them.

However, the most significant one among all is the 80386 of Intel which was introduced in 1986.

This processor came with a clock speed ranging between 16 MHz and 33 MHz and with 275000 transistors and 132 pins.

This year also saw the release of the Intel 80486 microprocessor that had a clock speed ranging between 16 MHz and 100 MHz, a total of 1.2 million transistors and 168 pins.

Fifth Generation:

The 5^th generation microprocessors came into existence in 1995 and the current microprocessors belong to this generation.

These microprocessors are called 64-bit microprocessors.

This era saw the release of 80856, Intel Pentium, Intel Pentium Pro and other microprocessors that allowed multiprocessing in a single system.

The core 2 microprocessor was invented by Intel in 2006 with a clock speed ranging between 1.2 GHz to 3 GHz.

These processors had as many as 291 million transistors.

Then there were the Core i3, Core i5, and Core i7 microprocessors with clock speeds ranging between 2 GHz and 3+ GHz.

Other 64-bit processors were also improved in this period such as Celeron, dual-core, quad-core, and octa-core processors.

At present there aren’t any mainstream 128-bit microprocessors available because it is still a long time to exhaust the 64-bit address space.

Being used at a steady rate of about 2 bits in every 3 years, only 48 bits of it has been used.

So, it will take some time for the 128-bit microprocessors to become mainstream.

List of Different Microprocessors

Here is the list of microprocessors manufactured by different companies in an alphabetical order.

The microprocessors developed and marketed by Adapteva are:

E16G301 and
E64G401.

The microprocessors developed and marketed by Ambric is:

Am2000.

The microprocessors developed and marketed by AMD are:

A10
A8
Am186
Am286
Am29000
Am29030
Am29035
Am29040
Am29050
Am386
Am486
Am5x86
Am8086
Am9080
Athlon
Athlon 64
Athlon 64 X2
Athlon II X4
Athlon MP
Athlon X2
Athlon X4
Athlon XP
Duron
K5
K6
K6-2
K6-2+
K6-III
K6-III+
Opteron
Phenom II X3
Phenom II X4
Phenom X3
Phenom X4
Sempron
Turion 64
Turion 64 X2
Ryzen 3
Ryzen 5
Ryzen 7
Ryzen 9 and
Ryzen Threadripper

The microprocessors developed and marketed by Atmel are:

AVR
AVR32 and
MARC4.

The microprocessors developed and marketed by Broadcom is:

Broadcom.

The microprocessors developed and marketed by Centaur Technology is:

WinChip.

The microprocessors developed and marketed by Clearspeed is:

CSX700.

The microprocessors developed and marketed by Cray Inc are:

MTA-2
Threadstorm and
Threadstorm4.

The microprocessors developed and marketed by Cypress Semiconductor is:

Cypress.

The microprocessors developed and marketed by Cyrix are:

486DX
486SLC
5×86
6×86 and
Cyrix III.

The microprocessors developed and marketed by Digital Equipment Corporation are:

Alpha 21064
Alpha 21064A
Alpha 21066A
Alpha 21164
Alpha 21164A
Alpha 21164PC
Alpha 21264
Alpha 21264A
Alpha 21264B
Alpha 21264C
Alpha 21364 and
StrongARM.

The microprocessors developed and marketed by Exponential Technology is:

X704.

The microprocessors developed and marketed by Fujitsu are:

microSPARC II
SPARC64 and
TurboSPARC.

The microprocessors developed and marketed by General Instrument are:

PIC
SBA and
Series 8000‎‎.

The microprocessors developed and marketed by HAL Computer Systems are:

SPARC64 and
SPARC64 II.

The microprocessors developed and marketed by Hitachi is:

harp-1.

The microprocessors developed and marketed by HP are:

PA-7000
PA-7100
PA-7100LC
PA-7150
PA-7200
PA-7300LC
PA-8000
PA-8200
PA-8500
PA-8600
PA-8700
PA-8700+
PA8800 and
PA8900.

The microprocessors developed and marketed by IBM are:

Power2
Power3
Power3-II
Power4+
Power5
Power6
Power7
PowerPC 7xx
PowerPC 970
PowerPC 602
PowerPC 603
PowerPC 620
PowerPC 630
PowerPC 601
PowerPC 601v
PowerPC 603e
PowerPC 603ev
PowerPC 604
PowerPC 604e
PowerPC 604ev
RS64 IV
RS64-II and
RS64-III.

The microprocessors developed and marketed by Intel are:

4004
4040
8008
80186
80286
80386 DX
80486 DX
80486 DX2
80486 DX4
8080
8086
8088
Atom
Celeron
Celeron D
Celeron M
Core 2 Duo
Core 2 Extreme
Core 2 Quad
Core 2 Quad Extreme
Core 2 Solo
Core Duo
Core i3
Core i5
Core i7
Core i7 Extreme
Core i9
Core Solo
EP80579
i860
i960
iAPX432
Itanium
Itanium 2
Pentium
Pentium 4
Pentium 4 EE
Pentium 4-M
Pentium D
Pentium EE
Pentium II
Pentium III
Pentium III Mobile
Pentium III Xeon
Pentium II Mobile
Pentium II Xeon
Pentium M
Pentium MMX
Pentium Pro
Quark and
Xeon.

The microprocessors developed and marketed by MediaTek is:

Hello.

The microprocessors developed and marketed by MIPS Technologies are:

3520
5900
7000
74K
R2000
R3000
R4000
R4200
R4300i
R4400
R6000
R8000 and
R10000.

The microprocessors developed and marketed by MOS Technology are:

6502 and
6510.

The microprocessors developed and marketed by Motorola are:

MC14500
6800
68000
68010
68020
68030
68040
68060
88000 and
PowerPC.

The microprocessors developed and marketed by National Semiconductor are:

IMP-4
IMP-8
IMP-16
COPS I
COPS II
MAPS and
NS32k.

The microprocessors developed and marketed by NexGen is:

Nx586.

The microprocessors developed and marketed by Phytium are:

FT-1200 and
FT-1500A.

The microprocessors developed and marketed by Qualcomm are:

MSM
MSM1
MSM2
MSM2300
MSM3000
MSM3100
MSM3300
MSM4500
MSM5000
MSM5105
MSM5100
MSM5200
MSM5500
MSM6xxx
MSM7xxx
Snapdragon
Snapdragon S1
Snapdragon S2
Snapdragon S3
Snapdragon S4
Snapdragon 200
Snapdragon 400
Snapdragon 600 and
Snapdragon 800.

The microprocessors developed and marketed by Quantum Effect Devices are:

R4600
R5000 and
RM7000.

The microprocessors developed and marketed by Rapport is:

Kilocore.

The microprocessors developed and marketed by Ross Technology is:

hyperSPARC.

The microprocessors developed and marketed by SGI are:

R12000
R12000A
R14000
R14000A
R16000
R16000A and
R18000.

The microprocessors developed and marketed by Sun Microsystems are:

microSPARC I
SuperSPARC I
SuperSPARC II
UltraSPARC
UltraSPARC II
UltraSPARC IIe
UltraSPARC IIi
UltraSPARC III Cu
UltraSPARC IIIi
UltraSPARC T1 and
UltraSPARC T2.

The microprocessors developed and marketed by Sunway or ShenWeiare:

SW-1
SW-2
SW1600 (SW-3) and
SW26010.

The microprocessors developed and marketed by Tesla (Czech) is:

MH 3000.

The microprocessors developed and marketed by Transmeta are:

Crusoe and
Efficeon.

The microprocessors developed and marketed by Western Design Center are:

WDC 65C02 and
WDC 65816.

The microprocessors developed and marketed by Western Digital are:

WD MCP-1600 and
WD CR1872.

The microprocessors developed and marketed by Zilog are:

Z80
Z8000 and
Z80000.

Basic Terms

There are a few basic terms that are used in microprocessors which are also good to know. These are:

Instruction Set – This refers to the set of commands that are understood by the microprocessor in machine language. It also refers to all of the probable instructions or subsets of instructions for the CPU to improve its performance in specific situations.
Bus – This refers to the set of conductors used to transmit data and address. It also controls the information sent to different elements of the microprocessor. There are usually three types of buses in a microprocessor namely, data bus, control bus, and address bus.
Instructions Per Cycle – Commonly referred to as IPC, this refers to the number of instructions executed by the processor in a single clock.
Clock Speed – This refers to the number of operations performed by the CPU per second and is usually expressed in Megahertz or Gigahertz. It is more commonly referred to as the Clock Rate.
Bandwidth – This refers to the number of bits processed by the CPU in a single instruction.
Word Length – This indicates the number of bits processed by the processor at a given time. For example, an 8-bit microprocessor at a time can process 8 -bit data. The type of microcomputer determines the world length which ranges from 4 bits to 64 bits.
Data Types – The microprocessor may support different types of data formats such as ASCII or American Standard Code for Information Interchange, binary, signed and unsigned numbers.

Characteristics

Ideally, there are three major characteristics of a microprocessor. These are:

Clock Speed
Word Size and
Instruction Set.

Design

The microprocessors come with several tiny components that work together to perform a given functions. These are:

The transistors
The registers and
Diodes.

The most important part of the microprocessor is the CPU of the Central Processing Unit. It processes data and instructions and also performs several calculations and other tasks.

The CPU is also called the main processor or central processor which comes with the following subparts:

The ALU or Arithmetic Logic Unit which performs the arithmetic and logical operations such as addition, subtraction, multiplication, division, greater than, less than and others on the data fed through the input devices or received from the memory
The CU or Control Unit which controls the data flow and instructions and manages the tasks executed by the CPU and
The register array which comprises registers such as B, C, D, E, H, L, and an accumulator and cats as memory areas to store input and calculation data, output results and more.

Some of the other parts of a microprocessor include a decoder which decodes the High Level Language instructions to Machine Language before passing them on to the CPU as well as an Instruction Register to store the instructions to be executed currently.

The microprocessor also comes with a bus architecture which helps in communication.

It is actually a collection of wires that use electric signals to transmit data and information.

Bus architecture consists of different types of buses as said above such as:

An address bus, which communicates address of given data and instructions
A data bus, which transfers data from one part to another and
A control bus, which manages the signals between the devices.

There is a memory as well in a microprocessor which also comes in different parts such as:

Primary Memory – This volatile internal memory stores data and instructions of the processor which is lost when the system is switched off. There are two types of primary memory namely, RAM or Random Access Memory and ROM or Read Only Memory.
Secondary Memory – This refers to the external non-volatile storage devices to store data permanently such as CD, DVD, and others.

Types of Microprocessors

There are different types of microprocessors available today though you may only find a few of them dominating the market.

CISC microprocessor:

The Complex Instruction Set Computer or CISC microprocessors help in simplifying the code and to make the instruction set shorter.

This reduces memory requirement.

The program size is reduced by using complicated addressing node which also reduces the memory cycle and execution time of a program.

The architecture of this processor includes special-purpose circuits that carry instructions at a very high speed. These instructions can be either very simple or very complex.

The complex instructions take longer time to be executed and are specified at the assembly language level. The compiler changes it from higher level to assembly.

The most significant benefits offered by the CISC microprocessors are reduced memory usage and time consumption.

It can perform several low-level operations such as loading from and storing into memory, an arithmetic operation by using very few registers and more.

A few examples of CISC microprocessors are:

Intel 386
Intel 486
Pentium
Pentium Pro
Pentium II
Pentium III
Motorola 68000
Motorola 68020
Motorola 68040 and more.

RISC microprocessor:

This is one of the major microprocessors that are considered to be an alternative to the CISC processors and come with simple instruction sets and addressing modes.

The RISC or Reduced Instruction Set Computer processors are faster and take less time to operate as they execute each instruction in only one clock cycle.

One of the special features of the RISC processors is that it allows increasing the register set by the users as well as the internal parallelism.

However, it usually has a fixed length of 32-bit of instruction.

The main downside of the RISC processors is that direct memory to memory transfer is not allowed and therefore it is hard to process complex addressing modes and instructions.

These processors are mainly used in modern electronic gadgets.

A few examples of RISC microprocessor are:

IBM RS6000
MC88100
DEC Alpha 21064
DEC Alpha 21164 and
DEC Alpha 21264.

EPIC microprocessor:

The EPIC or Explicitly Parallel Instruction Computing microprocessors use compilers to carry out instructions in parallel without needing to use higher clock frequencies.

The instruction is encoded into 128-bit bundles, each of which consists of 3 instructions encoded in 41 bits each along with a 5-bit template field such as the IA-64 or Intel Architecture-64.

Superscalar microprocessor:

These processors are fast enough to handle multiple tasks easily and produce the results without delay.

The superscalar microprocessors come with an extensive architecture structure that enables them to handle multiple instructions sets during a clock cycle.

There are several execution units in them that help in feeding different pipelines.

A few examples of superscalar microprocessors are:

Intel i960A
AMD29006 series
MC88100 and
MIPS R.

You will also get a few special function microprocessor variants based on their working operations. These are:

ASIC processor – The Application Specific Integrated Circuit microprocessors are designed to transmit protocols on handheld computers and are used across several industries such as communications, automotive, and more.
DSP – A short for Digital Signal Processor is also a special type of microprocessor that is typically built with MOS ICs or Metal Oxide Semiconductor Integrated Circuits to process digital signals as well as filter, measure and compress analog signals. The special memory helps it in controlling several data instructions. It is used in telecommunication, radar systems, digital image processing, mobile phones, speech recognition, and satellite technology.
SIMD processor – A short for Single Instruction, Multiple Data, the name of this microprocessor says it all. In this processor the Control Unit supervises a set of processing units and every processor is given the same instructions set from the CU but they work with different data in parallel. These processors are useful in multimedia applications helping in adjusting contrast of a digital image or volume of digital audio.
Symbolic processor – Mainly dealing with operations like algorithmic behavior, communication, and memory input-output, the symbolic processors are typically used in text retrieval, knowledge engineering, and machine intelligence.
Bit slice microprocessor – These processors use bit slicing technique to construct form modules of processors with lesser bit width to increase the word length. Each of these modules is of one-bit field or slice. These processors come with Arithmetic Logic Unit of 1, 2, 4, 8, or 16-bit control lines.
Transputer processors – A short for Transistor Computer, these processors are semiconductor based and come with integrated memory. These low-power, low-cost processors have serial communication lines supporting parallel computing.
Graphics processor – This refers to the Graphic Processor Unit or GPU which is a special electronic circuit that handles parallel processing of graphics and video rendering. These help in altering memory to speed up the creation of images in the frame incorporated for output and the parallel structure makes them so useful in the modern computing world. Usually mobile phones, embedded systems, personal computers, game stations, and workstations use GPUs.

Features of Microprocessor

Some of the most significant features of the microprocessor are:

Low cost due to the IC or Integrated Circuit technology
High speed operation due to better architecture
Smaller size due to large scale integration technology
Versatile nature due to ability to use in several applications
Low power consumption due to Metal Oxide Semiconductor technology
Less heat generation due to the use of semiconductor technology
Reliability due to lower failure rate of the semiconductors and
Portability due to its small size.

Where are Microprocessors Used?

Due to the useful features as mentioned above, you will see microprocessors being used is several electronic devices which includes and are not limited to:

Mobile phones
Electronic and video games
Kitchen appliances
Automobile emission control devices
Timing devices
Home thermal controls
Calculators
Telephone switching systems and
Security systems.

You will also see microprocessors are used in several different devices used in the industries to monitor and do different things such as:

Operations
Temperature
Speed
Pressure
Alert or warning system on extreme conditions
Automating office work and business processes.

Microprocessors are also used to:

Simplify publishing activities
Expedite information exchange through satellite and telephone network and
Making innovative devices for entertainment and photography.

Moreover, the microprocessors are used in a lot of devices that are specifically used in military applications and also in space research.

In short, the microprocessors are found in almost any device you use today that helps in doing your home and office jobs in a much better and faster manner and also stay connected with the rest of the world.

Why is the Microprocessor Important?

A microprocessor is important because without it the computer will not be able to perform any task that you want it to.

It takes the data input and processes it by performing different arithmetic and logical operations to produce the desired output.

The microprocessor helps the computer add and subtract, multiply and divide, compare and transfer numbers from one place to another.

In short, it is the central part of the computer without which the system will be ‘brain dead,’ with all puns intended.

Advantages

There are several benefits of using a microprocessor and it is all due to the design and functionality of these processors.

To be very specific, the use of microprocessors in the systems in an industry helps in a lot of ways such as:

Reducing operating cost
Optimizing control, monitoring, and money saving strategies
Ensuring uniformity in operations with automated processes
Improving responsiveness in product processing, specification and while making new additions
Incorporating better strategies to reduce product offset due to equipment failure
Improving plant safety
Improving communications between maintenance and operations managers and
Incorporating Relational Database Management and statistical strategies.

In general, the microprocessors in a computer helps in performing multiple tasks very fast because it helps in moving data very quickly between different memory locations and devices.

Disadvantages

Just like a coin has two faces, the microprocessors also come with some disadvantages.

Therefore, when you look at the flip side, the significant downsides of the microprocessors are:

Overheating if used continuously
Performance is dependent on the size of the data
Lack of floating point operations support
Bigger in size than the microcontrollers
Performance is based on machine language only
High overall cost and
Lack of any internal peripherals such as RAM, ROM and other I/O devices.

Most importantly, it is required to ensure that it does not come in contact with any other external devices.

Conclusion

Ideally, the microprocessors of today have really revolutionized modern computing.

And, thanks to this article, now you know what it is, how it works, as well as the specific reasons as to why it has become an integral part in the development process of everyday technology.