A system bus is responsible for maintaining all communication between the Central Processing Unit (CPU), system peripherals and memories. The system bus operates with a certain bus protocol to exchange data between a bus master and a bus slave. The bus protocol ensures to isolate all other system devices from interfering the bus while the bus master exchanges data with a bus slave. Bus master initiates the data transfer, and sends or receives data from a slave device or a system memory. Bus slave, on the other hand, does not have the capability to start data transfer.