Control Bus (ControlBus) is referred to as CB. The control bus is mainly used to transmit control signals and timing signals.Among the control signals, some are sent by the microprocessor to the memory and input and output device interface circuits, such as: read/write signals, chip select signals, interrupt response signals, etc.; some are fed back to the CPU by other components, such as: interrupts Application signal, reset signal, bus request signal, device ready signal, etc.
Therefore, the transmission direction of the control bus is determined by the specific control signal, which is generally bidirectional. The number of bits in the control bus is determined according to the actual control needs of the system. In fact, the specific situation of the control bus mainly depends on the CPU.
The control bus is connected together and completes and implements communication and data transmission between them. Therefore, the concept of bus is the basis for understanding the structure, working principle and interrelationship between components of PC and motherboard. .
These control information include the read and write signals of the CPU to the memory and the input and output interfaces, the interrupt requests or DMA request signals raised by the input and output interfaces to the CPU, the CPU's answer and response signals to these input and output interfaces, the input and output interfaces various working status signals and various other function control signals. The control bus travels between the CPU, memory, and input and output devices.
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