Microprocessor

Microprocessor  is the brain of computer, which does all the work. It  is an important part of a computer architecture without which you will not be able to perform anything on your computer. It is a programmable device that takes in input perform some arithmetic and logical operations over it and produce desired output. It accepts input as a binary data and after processing, it provides the output data as per the instructions stored in the memory. It also known as a CPU or central processing unit.  is a complete computation engine that is fabricated on a single chip (Programmable Multipurpose Silicon Chip).

 Block diagram of a microprocessor 

The microprocessor is made up of three main units

1)    Arithmetic  and  Logic  unit  (ALU)

-     It perform arithmetic and logical instructions based on computer instructions.

2)      Control unit (CU)

-     It control overall operations of the computer through signals.

3)      Registers (Internal Memory)

-     It holds the instruction and data for the execution of the processor.

Basics  of  Microprocessor 
A Microprocessor takes a bunch of instructions in machine language and executes them, telling the processor what it has to do. Microprocessor performs three basic things while executing the instructions.

1.     It performs some basic operations like addition, subtraction, multiplication, division and some logical operations using its Arithmetic and Logical Unit (ALU), new microprocessors also perform operations on floating point numbers also.

2.     Data in Microprocessor can move from one location to another.

3.     It has a Program Counter (PC) register that stores the address of next instruction based on the value of PC, Microprocessor jumps from one location to another and takes decision.

Characteristics of Microprocessors

A Microprocessor’s performance depends on the following characteristics

a.  Clock speed     b. Instruction set      c. Word size

a. Clock Speed

Every microprocessor has an internal clock that regulates the speed at which it executes instructions. The speed at which the microprocessor executes instructions is called the clock speed. Clock speed is measured in MHz (Mega Hertz) or in GHz (Gigahertz).

b. Instruction Set

A command which is given to a computer to perform an operation on  data is called an instruction. Basic set of machine level instructions that a microprocessor is designed to execute is called as an instruction set. This instruction set carries out the following types of operations:

 •  Data transfer

•  Arithmetic operations

•  Logical operations

•  Control flow

•  Input/output

c. Word Size

The number of bits that can be processed by a processor in a single instruction is called its word size. Word size determines the amount of RAM that can be accessed by a microprocessor at one time and the total number of pins on the microprocessor. Total number of input and output pins in turn determines the architecture of the microprocessor.