Microprocessor|Unit 1 |Introduction of Microprocessor


Defination:→ An integrated ciruit that contains all the funcation of a centeral processing unit of a computer .

Application of Microprocessor;

1)The microprocessor is used in personal computers.
2)It is used in military application.
3)it is used in Traffic Light control.
4)It is used in calculators and game Machine.
5)It is used in Mobile Phone and Television.
6)The microprocessor are used in medical instrument to measure temperature and blood pressure.
7)microprocessor is used in home applicances such as Micowave ovens,Washing maching etc.

Evolution of Microprocessor;

1)Microprocessor is made up of semi-conductor like silicon.
2)It is a combination of transistor.
3)Marcian E hoff,Masantosi shime,Stanlcy Mazor and federico foggin are the inventor of Microprocessor.

Intel 4004(2300)
Intel 8008(3500)
ZILOG Z80(6000)
Intel 8085(6500)
Intel 8086(29000)
M68000 (68000)
Z8000 (6500)
Intel80366 (275000)
M68020 (68000)
intel80486 (12 lakh)
Hp 32
Intel Pentium (31 lakh)
Intel Pentium ii(71 lakh)
Intel Pentium iii(95 lakh)

Von Neumaan Architecture;

1)Von neumaan Architecture was a member of the eckert-manchly team(developer of ENIAC)
2)Von neumann architecture was first published by john von neumaan in 1945
3)His computer architecture design consists of a control unit,logic unit,Memory unit,Registers and input output ports.
4)Von neumann architecture is based on the store program computer concepts,where instructions data and program data are store in the same memory.

fig:Von Neumaan Architecture

※ Centeral Processing Unit:→The centeral processing unit (CPU)is the electronic circuit responsible for executing the Instruction of s computer program. Sometimes it refered as the Microprocessor Or processor.The cpu Contains The ALU,CU and variety of registers.

※ Registers;→Registers are high speed storage areas in the Cpu.All data must be stored in a registers before it can be used.

MAR Memory Adress Register Hold the Memory location of data that need to be accessed
MDR Memory Data Register Hold data that is being transfered to or from memory.
AC Accumulator Where intermediate arithmetic and logic results are stored.
PC Program counter Contains the adress of the next instrucation to be excuted.
CIR Current Instruction Register Contains the cureent Instruction during processing.

※ ALU(Arithmetic and logic unit);→The ALU allows arithmetic add,subtract and logic (AND or not) operations to be carried out.

※ Control unit(CU);→ The control unit controls the operation of the computer's ALU,memory and input/output device,telling them how to the program instruction. It has just read and interpreted from the memory unit. The control unit also provides the timing and control signal required by the other computer component.

※memory Unit:→ The Memory Unit consist of RAM.Sometime it refered as Primary or main memory.Unlikely a hard disk(secondary Memory).THis memory is Fast and also direct accessible by the cpu.
RAM is split into partition.Each partitions.Each Partion consists of an address and its contents(both in binary form)

※Input Device;→A device that feeds data into a computer such as keyboard or Mouse is called Input device.

※Output Device;→An output device is any peripheral that receives data from a computer usually for display.


a)Arithmetic logic unit(AlU);

1)This unit executes all arithmetic and logical operation as specified by instrucation set and produces output.
2)THe result of addition subtraction and logical opertaion (AND or XOR) are stores in the registers or in memory unit or sent to output unit.

b)Register Array;

1)Consists of various registers.
2)Used for temporary storage of data during execution of data.

c)Control unit(CU);

1)Controls the operations of different instrucation.
2)provides necessary timing and control signals to all the operation in the microprocessor and peripherals involving memory.


1)Stores binary information such as instruction and data and provide these information to MP when required.
2)To execute programs the microprocessor reads data and instrucations from memory and performs the computing operations.

System Bus;

1)The system bus is a communaction path between microprocessor and peripherals
2)It is used to carry data,address and control signals
3)It consists;

Data Bus:Carries data
Address Bus:Carries adderss
Control Bus:Caries control signal

Input/Output Bus;

1)Input unit is used to input instrucation or data to the microprocessor exernally.
2)Output unit is used to carry out the information from the Microprocessor unit.

Types of Microprocessor


1)RISC stand for reduced instrucation set computer.
2)RISC processor has a limited number of instrucation because of simple and instrucation it execute it very fast.


1)CISC processor stand for complex instrucation set computer.
2)CISC processor can perform multi-step operations.
3)It contains large number of complex instrucation.

c)Spical processor;

1)Some of special purpose processor Input/Output processor.
2)This Microprocessor have a local memory of it's own which is used to handel only Input,Output processor for a Keyboard,Mouse control.

Different Between RISC and CISC;

1)The origanal Microprocessor ISC(industary Stand Archiletecture) Redsigned ISC that emerged in the early 1980s
2)Hardware centric design Software centric design
3)More efficient use of RAM Heavy use of RAM
4)Complex and variable length instrucations Simple standard instrucation
5)Many support microcode Only one layer of Instrucation
6)Large number of instrucations Small number of fixed length instrucation
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