It is a general-purpose device that can be programmed to carry out a set of arithmetic or logic operations. In other words, a microprocessor is a programmable electronics chip that has computing and decision-making capabilities.
It is capable of doing the following tasks:
- Receives input data or instruction (INPUT UNIT)
- Carries out arithmetic or logic operations as per the instructions on the data (ALU)
- Stores the data and instructions (MEMORY)
- Gives the results of the computations (OUTPUT UNIT)
- Controls the functions of all devices (CONTROL UNIT)
8085 & 8086 Microprocessor ICs
Microprocessor Images
Basic Building Block of Computer
The building block of the computer includes different units as shown in the below image.
Input Unit
Receives input from different input devices like keyboard, mouse, etc.
ALU Unit
Performs all arithmetic operations like addition, subtraction, etc. and logical operations like AND, OR, XOR, etc.
Control Unit
Contains Instruction Register and Program Counter.
Program Counter (PC):
Register which contains the address of the memory location, the contents of which are to be fetched by the CPU.
Instruction Register (IR):
A register which stores the instruction temporarily and which is further to be decoded.
- The memory unit stores the data and instruction.
- The ALU, Control Unit, and Register are combined to form a CPU which is also known as MICROPROCESSOR.
BUS Architecture
- All the three units, I/O, Memory, and CPU must be able to communicate with each other.
- They can be communicated with the help of the bus.
- A bus is a group of conducting wires or lines over which electrical signals are transmitted.
Three buses are used in this system.
- Address Bus
- Data Bus
- Control Bus
Address Bus
- Group of conducting wires which carries ADDRESS only
- It is unidirectional (data flow in one direction)
- Over the address bus, the microprocessor transmits the address of that I/O device or memory location which is desires to access (data out of microprocessor)
Data Bus
- Group of conducting wires which carry DATA only.
- It is bi-directional (data flow in both directions)
- The microprocessor uses a data bus to send and receive the data to and from memory or Input/Output devices.
Control Bus
- Group of conducting wires, which is used to generate timing and control signals to control all associates peripherals.
- It is used for transmitting and receiving the control signals between the microprocessor and various devices.
Some Control Signals
- Memory Read
- Memory Write
- I/O Read
- I/O Write
- Opcode Fetch
Microprocessor Application
- PC, Machines, Calculator, Car, Bike, Bus, etc.
- Communication Devices like Switch, Routers, Hub, etc.
- Industrial machines like Robots, etc.
- Home Appliances like Bell, Fridge, AC, Micro oven, etc.
- Test Instruments like CRO, Oscilloscope, etc.