Question

what is the purpose of control bus how many bits can transmit

Answer 1

I think it around 32 bit

Answer 2

The CPU transmits a variety of control signals to components and devices to transmit control signals to the CPU using the control bus. One of the main objectives of a bus is to minimize the lines that are needed for communication. An individual bus permits communication between devices using one data channel. The control bus is bidirectional and assists the CPU in synchronizing control signals to internal devices and external components. It is comprised of interrupt lines, byte enable lines, read/write signals and status lines.