Computer Science (Paper-II)
1. Introduction to Microprocessor and organization of 8085 microprocessor
➢ Evolution of Microprocessor
After the invention of integrated circuit(IC) semiconductor technology has
undergone so many changes. IC means more than one chip fabricated or integrated on a
single chip, It may consists of transistors, diodes, resistors on a single chip.
- Small scale integration
In this technology more than one but less than 100 logic gate chips was integrated
on single chip.
- Medium scale integration
In this technology more than 100 but less than 1000 logic gate chips was integrated
on single chip.
- Large scale integration
In this technology more than 1000 but less than 10000 logic gate chips was
integrated on single chip.
- Very large scale or Super large scale integration
In this technology it became possible to integrate more than 10000 logic gate chips
on single chip.
➢ Generations of Microprocessor
1. First generation
In 1971, Intel introduced first microprocessor in the market was Intel-4004. It was
first 4-bit microprocessor developed by scientist Federico Faggin.
In 1972 Intel introduced the 8008 first 8-bit microprocessor in the market.
Eg:- Intel-4040, Toshiba’s T-3472
2. Second generation
In 1976, Intl introduced 8085 microprocessor. It was 8-bit microprocessor.
Development of microprocessor has been in the direction towards a complete
microcomputer system with CPU, ROM, RAM, Clock, I/O ports, all in single package.
Eg:- Intel 8048, Motorola MC-6801
3. Third generation
In 1978, Intel introduced 8086 microprocessor now called as APX-86. It was first
16-bit microprocessor developed by scientists Stephen Mors and Druce Revenal. it
can perform all the functions of minicomputer.
Eg:- Intel-8086, 8088, Zylog Z-8000
, 4. Fourth generation
In 1981, Intel introduced 80386 microprocessor. It was first 32-bit microprocessor.
It can address a 4GB physical memory.
Eg:- M-68020, HP-32, iAPX-432
➢ Microprocessor
Microprocessor is a multipurpose programmable logic device that reads binary data
from storage device i.e. memory accept that data as input process as per the instructions
and provide result as output.
Fig: Microprocessor
- It is divided into three parts
1. ALU
2. Register
3. Control unit
1. ALU
- It is Arithmetic and Logic unit .
- It is used to perform arithmetic and logic operations, arithmetic operations are
addition, subtraction etc and logical operations are AND, OR, NOT etc.
2. Register
- It is temporary memory.
- It stores data temporarily at the time of execution of program.
3. Control Unit
- It provides timing and control signals to the operations.
- It is use to control flow of data between microprocessor, memory and peripherals.
➢ Microprocessor with microprocessor based system
- There are three parts of microprocessor based system that works with
microprocessor.
1. Memory
2. Peripherals
3. System Bus
, 1. Memory
- Memory is a storage device. It stores data and instructions in binary form.
- Microprocessor reads data and instructions from memory for performing operation.
- It also used to store result.
2. Peripherals
- Peripherals means Input and Output devices.
- Input devices that are Keyboard, Mouse etc. which transfer data from outside of the
computer to the inside of the computer or microprocessor.
- Output devices that are Printer, Monitor etc. which transfer data from inside of the
computer or microprocessor to the outside of the computer.
3. System Bus
- System bus is bunch of wires used to transfer data from one place to another place.
- It is called communication path between microprocessor, memory and peripherals.
Fig: Microprocessor with microprocessor based system
➢ Block diagram of ALU
- ALU is Arithmetic and Logic Unit
- It is used to perform arithmetic and logic operations.
- It is 8 bit unit
- It consists of:
• Adder
It is used to perform arithmetic operations.
• Shifter
It is used to perform logical operations.
• Status register
It is used to show the status of program. It set or reset according to the accumulator.
• Temporary register
It is used to stores data temporarily at the time of execution of program.
• Accumulator
It is used to store result of program i.e. ALU operation.
• System bus
It is used to transfer data from one place to another place.
1. Introduction to Microprocessor and organization of 8085 microprocessor
➢ Evolution of Microprocessor
After the invention of integrated circuit(IC) semiconductor technology has
undergone so many changes. IC means more than one chip fabricated or integrated on a
single chip, It may consists of transistors, diodes, resistors on a single chip.
- Small scale integration
In this technology more than one but less than 100 logic gate chips was integrated
on single chip.
- Medium scale integration
In this technology more than 100 but less than 1000 logic gate chips was integrated
on single chip.
- Large scale integration
In this technology more than 1000 but less than 10000 logic gate chips was
integrated on single chip.
- Very large scale or Super large scale integration
In this technology it became possible to integrate more than 10000 logic gate chips
on single chip.
➢ Generations of Microprocessor
1. First generation
In 1971, Intel introduced first microprocessor in the market was Intel-4004. It was
first 4-bit microprocessor developed by scientist Federico Faggin.
In 1972 Intel introduced the 8008 first 8-bit microprocessor in the market.
Eg:- Intel-4040, Toshiba’s T-3472
2. Second generation
In 1976, Intl introduced 8085 microprocessor. It was 8-bit microprocessor.
Development of microprocessor has been in the direction towards a complete
microcomputer system with CPU, ROM, RAM, Clock, I/O ports, all in single package.
Eg:- Intel 8048, Motorola MC-6801
3. Third generation
In 1978, Intel introduced 8086 microprocessor now called as APX-86. It was first
16-bit microprocessor developed by scientists Stephen Mors and Druce Revenal. it
can perform all the functions of minicomputer.
Eg:- Intel-8086, 8088, Zylog Z-8000
, 4. Fourth generation
In 1981, Intel introduced 80386 microprocessor. It was first 32-bit microprocessor.
It can address a 4GB physical memory.
Eg:- M-68020, HP-32, iAPX-432
➢ Microprocessor
Microprocessor is a multipurpose programmable logic device that reads binary data
from storage device i.e. memory accept that data as input process as per the instructions
and provide result as output.
Fig: Microprocessor
- It is divided into three parts
1. ALU
2. Register
3. Control unit
1. ALU
- It is Arithmetic and Logic unit .
- It is used to perform arithmetic and logic operations, arithmetic operations are
addition, subtraction etc and logical operations are AND, OR, NOT etc.
2. Register
- It is temporary memory.
- It stores data temporarily at the time of execution of program.
3. Control Unit
- It provides timing and control signals to the operations.
- It is use to control flow of data between microprocessor, memory and peripherals.
➢ Microprocessor with microprocessor based system
- There are three parts of microprocessor based system that works with
microprocessor.
1. Memory
2. Peripherals
3. System Bus
, 1. Memory
- Memory is a storage device. It stores data and instructions in binary form.
- Microprocessor reads data and instructions from memory for performing operation.
- It also used to store result.
2. Peripherals
- Peripherals means Input and Output devices.
- Input devices that are Keyboard, Mouse etc. which transfer data from outside of the
computer to the inside of the computer or microprocessor.
- Output devices that are Printer, Monitor etc. which transfer data from inside of the
computer or microprocessor to the outside of the computer.
3. System Bus
- System bus is bunch of wires used to transfer data from one place to another place.
- It is called communication path between microprocessor, memory and peripherals.
Fig: Microprocessor with microprocessor based system
➢ Block diagram of ALU
- ALU is Arithmetic and Logic Unit
- It is used to perform arithmetic and logic operations.
- It is 8 bit unit
- It consists of:
• Adder
It is used to perform arithmetic operations.
• Shifter
It is used to perform logical operations.
• Status register
It is used to show the status of program. It set or reset according to the accumulator.
• Temporary register
It is used to stores data temporarily at the time of execution of program.
• Accumulator
It is used to store result of program i.e. ALU operation.
• System bus
It is used to transfer data from one place to another place.
