Introduction to  Microprocessor


                   Figure: Microprocessor, Microcomputer and Microcontroller

Microprocessor:

Microprocessor is a controlling unit of a micro-computer, fabricated on a small chip capable of performing ALU (Arithmetic Logical Unit) operations and communicating with the other devices connected to it.

Microprocessor consists of an ALU, register array, and a control unit. ALU performs arithmetical and logical operations on the data received from the memory or an input device. Register array consists of registers identified by letters like B, C, D, E, H, L and accumulator. The control unit controls the flow of data and instructions within the computer.

Block Diagram of a Basic Microcomputer:



1. Microprocessor (MPU)

Definition:
A microprocessor is the central processing unit (CPU) of a computer integrated into a single chip. It requires external components (like memory, I/O ports, timers) to function.

Key Features:

  • Only CPU on a chip.
  • Needs external RAM, ROM, and I/O to operate.
  • Used in personal computers, servers, and high-performance systems.
  • Good for complex tasks and multitasking.

Examples: Intel Core i7, AMD Ryzen, Intel 8086

2. Microcomputer

Definition:
A microcomputer is a complete computer system built around a microprocessor. It includes CPU, memory (RAM/ROM), I/O ports, and storage, often on a single motherboard.

Key Features:

  • A small, general-purpose computer.
  • Has all components of a computer: CPU + memory + I/O + storage.
  • Used in education, small business, and home computing.

Examples: Laptops, Desktops, Raspberry Pi (in some cases)

 

3. Microcontroller (MCU)

Definition:
A microcontroller is a self-contained system with a CPU, memory (RAM and ROM), and I/O peripherals all embedded on one chip.

Key Features:

  • All-in-one chip: CPU + RAM + ROM + I/O + timers + ADC
  • Used in embedded systems (e.g., appliances, cars, IoT).
  • Optimized for specific control tasks.
  • Low power, low cost.

Examples: Arduino (ATmega328), PIC, STM32, 8051


Comparison Table:

Feature

Microprocessor

Microcomputer

Microcontroller

CPU

Yes

Yes (as part of system)

Yes

RAM, ROM

External

Included (as a system)

 

Built-in

I/O Ports

External

Included

Built-in

Purpose

General-purpose computing

General-purpose system

Specific embedded tasks

Cost & Power

High

Moderate

Low

Application

PCs, servers

Laptops, desktops

Embedded systems, automation like Washing Machine, Micro oven