Microcontroller in Basic Bus Structure

Three Bus Architecture

Normally , a digital action in a Microprocessr-Based System Can Be Described By a three bus structure. A microprocesssor-based system devides any instruction to be executed into certain basic activities. these basic activities are Accomplished by Generating one or more hardware actions ,such as :
1] Data transfer between memory and processor
2] Data transfer between I/O and processor
3] Manipulation Of internal registers
4] Direct memory access

The Three bus structure contains three buses :
 
1) data bus,
2) address bus and
3) control bus
 
They are named based on the signal they carry :
 
1]THE DATA BUS
The data bus contains of 8,16 to 32 parellel signal lines. Data bus is provides a physical path for communication of data to be transferred.the signal is required to flow in both directions, hence it is BIDIRECTIONAL
 
2] THE ADDRESS BUS
Tthe address bus consists of 16,20,24,parellel signal lines.its output the address to eneble correct path for communication. the information is given by the processor , hence address bus is UNIDIRECTIONAL
 
3] THE CONTROL BUS
Tthe control bus consists of 4 to 10 parellel lines. the CPU sends out signals on the control bus to eneble the output of addressed memory devices or port devices.