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Basics of Computers Microprocessor Concepts

Basics of Computers Microprocessor Concepts

Microprocessor is the computer's core, which performs all the work. It is a computer processor that integrates all of the CPU (Central Processing Unit) functions on a single IC (Integrated Circuit) or on a few ICs at most. Only implemented microprocessors in the early 1970's. 4004 was Intel's first general purpose microprocessor used in the construction of personal computers. The arrival of microprocessors with a low cost general intent was instrumental in the growth of modern society, as it has.

Microprocessors Characteristics

Microprocessors are multi-purpose devices that can be built for specific or common functions. Laptop and smartphone microprocessors are general purpose whereas specialized ones are designed for graphical processing or machine vision. There are some traits common to all microprocessors.

These are the key characteristics of a microprocessor –

  • Clock speed
  • Instruction set
  • Word size

Clock Speed

Growing microprocessor has an internal clock that controls the speed at which instructions are performed, and often synchronizes them with other components. The speed at which instructions are performed by the microprocessor is called clock rate. Clock frequencies are expressed in MHz or GHz where 1 MHz represents 1 million cycles per second and 1 GHz is equal to 1 billion cycles per seconde.

Microprocessors usually have clock speeds in the region of 3 GHz which is the highest that current technology can reach. Speeds greater than this produce sufficient heat to destroy the chip itself. To solve this, manufacturers utilize several processors that work on a chip in parallel.

Word Size

The number of bits which a processor may process in a single instruction is called their word size. Word size specifies the volume of RAM that can be reached on the microprocessor in one go and the total number of pins. The cumulative number of input and output pins in effect specifies the microprocessor architecture.

The first commercial Intel 4004 microprocessor had been a 4-bit processor. It had 4 pins for input and 4 pins for output. The number of output pins shall also be equal to the number of pins received. Most microprocessors actually use 32-bit or 64-bit architecture.

Instruction Set

A command given to a digital computer is considered an instruction to perform an action on a piece of evidence. Simple series of machine level instructions programmed to run a microprocessor is named the instruction set. Such guidelines perform all kinds of activities –

  • Data transfer
  • Arithmetic operations
  • Logical operations
  • Control flow
  • Input/output and machine control

Microprocessor Components

The processors of today are very tiny relative to the first microprocessors, but they do have some fundamental components right from the first model.

  • CPU
  • Bus
  • Memory


CPU is produced as an integrated circuit (VLSI) of very wide size and has these parts -

  • Register of Instructions − Contains the instructions to be executed.
  • Decoder − It decodes the instructions (converts to machine level language) and sends them to the ALU (Arithmetic Logic Unit).
  • ALU − Arithmetic, logical, memory, register, and program sequencing operations include circuits.
  • Register − Holds intermediate results obtained through processing of the programme. Registers are used instead of RAM to retain these information, as accessing registers is almost 10 times quicker than accessing RAM.


Connection lines used to connect the microprocessor chip 's internal parts are called bus. A microprocessor has three types of buses −

  • Data Bus − Lines carrying data from and to the memory are named data buses. It is a microprocessor's bidirectional bus with a width equal to the word-length.
  • Address Bus − A unidirectional carrying address of a memory position or I / O port from CPU to memory or I / O port is responsible for this.
  • Control bus − Control bus are named monitor bus lines that hold control signals such as clock signals, interrupt signal or ready signal. They 're also bidirectional. Signal that denotes the readiness of a system to process is named ready signal. Signal that asks a device to interrupt the operation is called an interrupt.


Microprocessor has two memory types;

  • RAM − Random Access Memory is a volatile memory that can be erased as control is disconnected. Both details and documentation are held in RAM.
  • ROM − Read Only Memory is non-volatile memory whose data stays unchanged even when control is turned off. Microprocessor will read from it any time it likes but cannot write to it. It is pre-programmed by the manufacturer with most essential data such as the booting sequence.