Microprocessor-Based Personal Computer Systems

 Microprocessor-Based Personal Computer Systems are the systems that are built using microprocessors.

Fig.- Microprocessor Bassed Personal Computer System

There are four parts of microprocessor bussed system-
-Microprocessor Unit
-I/O Devices
-Memory
-System Bus

Microprocessor Unit

microprocessor unit is the brain of the microprocessor bassed computer systems. In This unit is the unit in which all the operations are performed. Any type of command is run in this unit and gives us output. There are many types of operations in a computer such as arithmetic operations, logical. All these operations are performed in the microprocessor unit. Operation and Decision Making Operation

Microprocessor unit has three segments-
1. Arithmetic and Logic Unit
2. Register Array
3. Control Unit

Arithmetic and Logic Unit

Different types of functions are performed in ALU. For example -
Arithmetic operation like addision, subtraction.
Logic operation like AND, OR, EX-OR etc.

Register Array

These register are primarily used to store data temporarily during the execution of a program.

There are two types of registers -
1. User accesible - User Accesible Registers can be accessed by user through instruction or program.
2. Internal - Internal Register can not be accessed by the user. These register is used only by microprocessor.

Control Unit

A control unit (CU) is an integrated circuit in a processor that controls inputs and outputs. It receives instructions from a program, then passes them to the Arithmetic Logic Unit (ALU). The ALU performs the appropriate calculations and sends the resulting values ​​back to the control unit.

I/O(Input/Output) Unit

Microprocessor communicates with ouside world with help of I/O (Input/Output) Devices.
These I/O (Input/Output) devices (including memory) are also known as peripherals.

The Input Devices such as keyboard switches, A/D converters, transfer binary information (data and instruction) from the outside world to the microprocessor.

The Output Devices transfer data from the microprocessor to the outside world.
Output Devices - LEDs, CRT or video screen, D/A converter etc.

Memory Unit

Momory stores binary information such as instruction and data.
To execute programs, the microprocessor read instruction and data from memory. Than microprocessor perfoms the computing operation in its ALU section.
after execution results are either results are either transferred to the output device for display or stored in the memory for later use.

There are two types of memory which are used -
1. ROM (Read-Only Memory)-
THe ROM is used to store programs that do not need alterations. For example system programs, moniter programs etc. Programs stored in the ROM can only be read, they cannot be altered.

2. Ram (Random-Access Memory) also known as Read/Write Memory
The Read/Write Memory is also known as user memory. it used to store user programs and data.

System Bus

The bus which is a group of wires is one by which information is transferred. All peripheral devices are connected to the microprocessor through the bus.

There are three types of buses in a microprocessor:-
1. Address Bus
2. Data Bus
3. Control Bus