MicroProcessor and Microcontroller

What is the difference between MicroProcessor and Microcontroller?

What is MicroProcessor and Microcontroller?

To make a Computer system,only microprocessor is not sufficient.It is necessary to add other peripheral devices such as RAM(Random Accessible memory),ROM(Read Only Memory),decoders,drivers to make complete microcomputer system.In addition,special purpose devices,such as interrupt controller,programmable timers,programmable I/O devices,DMA controllers may be added to improve the capability and performance and flexibility of a microcomputer.What is the difference between the two?


A MicroProcessor is a general purpose digital computer Central Processing Unit(CPU).which fetches ,decodes and executes instructions.It consists of Arithmetic Logical Unit(ALU),an array of registers and a control unit.

The below picture shows a MicroProcessor CPU which contains ALU ,Program Counter(PC),a Stack Pointer some registers and circuits.

Microprocessor BlockDiagram
MicroProcessor BlockDiagram

To make a complete microcomputer,one must add memory such as Read Only Memory(ROM) and Random Access Memory(RAM).A few microprocessor programs are stored in ROM.The ROM based programs are primarily fixed Programs that operates Peripheral devices.For example Personal Computer(PC).In the ROM in a PC has permanent programs to control Input and Output devices.


I will shout microcontroller is a true Computer on a Chip.The microcontroller has built-in ROM,RAM,parallel I/O,serial I/O and clock circuit.Microcontroller has on-chip (built-in) peripheral devices .These on-chip peripherals make it possible to have single chip microprocessor system.

Advantages of Microcontrollers:

  • Built-in Peripherals and has very speed.
  • Hardware reduces due to single chip.
  • Less hardware reduces PCB (Printed Circuit Board) Size.
Microcontroller Block Diagram
Microcontroller Block Diagram

Difference between Microprocessor and Microcontroller:


  • Microprocessor contains ALU control unit and timing circuit different registers and interrupt circuits.
  • It has many instructions to move data between memory and CPU.
  • It has many instructions to move data between memory and CPU.
  • It has one or two bit handling instruction.
  • Microprocessor based system requires more hardware.


  • Microcontroller contains microprocessor memory(ROM&RAM) I/O interfacing circuit and peripheral devices.
  • It has one or two instructions to move data between memory and CPU.
  • It has many bit handling instructions .
  • Microcontroller based system requires less hardware reducing the PCB(Printed Circuit Board) size.