Basics of Microprocessor and Microcontroller

Microcomputer, microprocessor, and microcontroller are all electronic devices used for processing data, but they differ in their functionality and architecture. Let’s understand some Basics of Microprocessor and Microcontroller and microcomputer.


  • A microprocessor is a central processing unit (CPU) on a single integrated circuit (IC) chip. It is essentially the “brain” of a computer or other electronic device, responsible for executing instructions and performing arithmetic and logical operations.
  • Microprocessors typically do not have built-in memory, input/output (I/O) interfaces, or other peripheral components, and must be connected to these components externally.
  • A microprocessor is a clock-driven semiconductor device consisting of electronic logic circuits manufactured by using either a large-scale integration (LSI) or very-large-scale integration (VLSI) technique.
  • In large computers, a CPU performs these computing functions. The Microprocessor resembles a CPU exactly. The microprocessor is in many ways similar to the CPU but includes all the logic circuitry including the control unit, on one chip.

Microcomputer- A Microprocessor System

  • The microprocessor is capable of performing various computing functions and making decisions to change the sequence of program execution.
  • The microprocessor can be divided into three segments for the sake of clarity. – They are: arithmetic/logic unit (ALU), register array, and control unit.
  • A microcomputer, on the other hand, is a complete computer system built around a microprocessor.
  • It typically includes not only a microprocessor, but also memory (RAM and ROM), I/O interfaces (such as serial and parallel ports), and other peripheral components (such as a keyboard, display, and storage devices).
  • Microcomputers are usually designed for general-purpose computing, and can be used for a wide range of applications, including word processing, web browsing, and gaming.
  • The block diagram of a microcomputer is shown below.
Basics Of Microprocessor And Microcontroller
  • Arithmetic/Logic Unit: This is the area of the microprocessor where various computing functions are performed on data. The ALU unit performs such arithmetic operations as addition and subtraction, and such logic operations as AND, OR, and exclusive OR.
  • Register Array: This area of the microprocessor consists of various registers. These registers are primarily used to store data temporarily during the execution of a program and are accessible to the user through instructions.
  • Control Unit: The control unit provides the necessary timing and control signals to all the operations in the microcomputer. It controls the flow of data between the microprocessor and memory and peripherals.
  • Memory: Memory stores such binary information as instructions and data, and provides that information to the microprocessor whenever necessary. To execute programs, the microprocessor reads instructions and data from memory and performs the computing operations in its ALU section. Results are either transferred to the output section for display or stored in memory for later use. Read-Only memory (ROM) and Read/Write memory (R/WM), popularly known as Random- Access memory (RAM).
  • I/O (Input/Output): It communicates with the outside world. I/O includes two types of devices: input and output; these I/O devices are also known as peripherals.
  • System Bus: The system bus is a communication path between the microprocessor and peripherals: it is nothing but a group of wires to carry bits.


  • A microcontroller is a small, low-cost, computer-on-a-chip device that contains a processor, memory, and input/output (I/O) peripherals. It is designed to control specific hardware functions in embedded systems, such as appliances, automobiles, medical devices, and industrial automation equipment.
  • The basic architecture of a microcontroller includes a central processing unit (CPU), memory, input/output (I/O) ports, and timers/counters.
  • The CPU executes instructions stored in memory, while the I/O ports allow the microcontroller to interact with external devices such as sensors, displays, and motors. The timers/counters are used to generate precise timing signals for controlling events in real-time.
  • Microcontrollers are available in various sizes and shapes, from small surface-mount packages to larger, dual in-line packages. They are programmed using specialized software tools that enable the user to write, compile, and download the code onto the microcontroller.

Some of the key features and advantages of microcontrollers include:

  • Low cost and low power consumption
  • Small size and high level of integration
  • Real-time processing capabilities
  • On-chip memory and I/O peripherals
  • Availability of specialized development tools and support from vendors

Comparison between Microprocessor, Microcomputer and Microcontroller






It is a single chip CPU of microcomputer.

It is multichip like single board or multiboard system.

It is a single chip microcontroller.


It is used in general purpose computer system like PC.

It is used for personal computing and control application.

It is used in application specific system.


It does not have on chip ROM, RAM, IO ports, timers etc.

It has off chip ROM, RAM, IO ports, timers etc.

It has on chip ROM, RAM, IO ports, timers etc.


It is used as main CPU of computer.

It is used as computer and control application.

It is used only for control application.


The system is user programmed.

The system is user programmed.

The system is preprogrammed.


Area of system is very large.

Area of system is very large.

Area of system is small.


Power consumption is more.

Power consumption is more.

Power consumption is less.


Speed is slow.

Speed is slow.

Speed is fast.


System cost is more.

System cost is more.

System cost is less.

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