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Elementary introduction to the basic function of controller
Apr 21, 2017

Data buffering: A buffer must be set in the controller because the rate of I/O devices is low and the CPU and memory rate are high. In the output, use this buffer to temporarily save the data from the host high-speed, the data in the buffer is then transmitted to the I/O device at the rate of the I/O device; When input, the buffer is used for staging data from the I/O device, pending receipt of a batch of data, and then transmitting the data in the buffer to the host at a high speed. Error control: The device controller also controls error detection for data transmitted by I/O devices. If an error is found in the transfer, the error detection code is usually placed and reported to the CPU, so the CPU will be the data transmitted to the void, and again to carry on a transfer. This ensures the correctness of data entry. Data exchange: This refers to the realization of the CPU and controller, the controller and the equipment between the data exchange. For the former, it is through the data bus, the CPU in parallel to write the data to the controller, or from the controller in parallel to read the data; for the latter, the device enters data into the controller, or transmits it from the controller to the device. To do this, you must set up the data registers in the controller.