Introduction to Microprocessors

Introduction to Microprocessors

Gursharan Singh Tatla
mailme@gursharansingh.in
www.eazynotes.com

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Introduction to Microprocessors
 The microprocessor is one of the most important

components of a digital computer.
 It acts as the brain of the computer system.
 As technology has progressed, microprocessors

have become faster, smaller and capable of doing
more work per clock cycle.
 Sometimes, microprocessor is written as

µP.

( µ is pronounced as Mu )
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Introduction to Microprocessors
 Definition:

Microprocessor is the controlling unit or CPU of a
micro-computer, fabricated on a very small chip capable
of performing ALU operations and communicating with
the external devices connected to it.

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A Computer
 A computer:
 Accepts the data from the user.
 Stores the data and the set of instructions supplied by

the user in memory.
 Processes the data according to the instructions in the

processing unit.
 Communicates the result to the user or stores it for

further reference.

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A Computer
 A computer has the following units:
 Input Unit
 Output Unit

 Memory Unit
 Central Processing Unit

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A Computer
 INPUT UNIT
 The input unit consists of the devices which accept the data and

instructions from the user and communicates it to the CPU.
 The various input devices are: keyboard, mouse, joystick, trackball

etc.

 OUTPUT UNIT
 It provides the result of the various operations performed by the

CPU to the user.
 The various output devices are: printers, monitors, loudspeakers

etc.
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A Computer
 CENTRAL PROCESSING UNIT (CPU)
 The CPU is the heart and nerve centre of the computer.
 It fetches the instruction and data from the peripheral

devices and performs all the arithmetic operations, takes
logical decision and control the operation of all other units.  Various sub-blocks of the central processing unit are:
 Arithmetic and Logic Unit (ALU)

 Timing & Control Unit
 Registers

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A Computer
 ARITHMETIC AND LOGIC UNIT (ALU)
 This unit perform all the logical and arithmetic operations.  Various arithmetic operations are: addition, subtraction, increment and

decrement etc.
 Various logical operations are: AND, OR, NOT, XOR, etc.

 TIMING AND CONTROL UNIT
 This unit controls the entire operations being performed by the system.  It controls the operations of ALU, input/output devices and memory unit.  This unit interprets the instructions and generates various timing and control

signals.
 REGISTERS
 A register is a very small amount of very fast memory that is built into the CPU

in order to store the current data and instructions which are being executed by the CPU.
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A Computer
 MEMORY UNIT
 It stores the program statement and the data i.e. the

information supplied from the input unit.
 It also stores the final output.
 This is connected to the CPU by means of a bidirectional

bus.
 The CPU processes the information as taken from the

memory and performs the operations in the ALU section.
 The results are either transferred to the output unit or stored

in the memory for later use by the CPU.

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A Micro-Computer
 As the name implies, microcomputers are small

computers.
 The block diagram of the microcomputer is similar to

the computer except that the central processing unit
of the microcomputer is contained in a single IC
called the microprocessor.

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A Micro-Computer
 A microprocessor is a LSI (Large Scale Integration) IC

that does almost all the functions of the...