BUS System

   Definition: BUS is a means of transporter / channel contained within a microprocessor (CPU) that connects the microprocessor to the outside world, Only devices addressed by the signals pay attention to them, the others discard the signals.

The microprocessor (CPU), there are 3 basic BUS system:

•  Data BUS        (bi-directional)
•  Address BUS     (uni-directional)
•  Control BUS     (uni-directional)  

A .Data Bus  

• Handles the transfer of all data and instructions between  functional areas of the computer. 
• The data bus is usually used as a taxonomy of microprocessor concerned.
• Only transmit in one direction at a time.
• Used to transfer instructions from memory to the CPU for execution.
• Used to transfer data between memory and the I/O section during input/output operation.

BUS

B. Address BUS

• Consists of all the signals necessary to define any of the possible memory address locations within the computer.
• Carrier to the address of the microprocessor component supporters.
• An address is defined as a label, symbol, or other set of characters used to designate a location or register where information is stored.
• Supporting components in a computer system must have a UNIQUE address. 

C. Coontrol BUS

• Carrier signal between the microprocessor control and support equipment in the continuity of communication between the parts of the computer system.
• Used to transmit a variety of individual signals (read, write, interrupt, acknowledge, and so forth) necessary to control and coordinate the operations of the computer.