INPUT/OUTPUT CONTROL SYSTEM

摘要

The system connects through a common bus with a central control unit and is connected by way of an external bus with an input-output unit. This provides for control of data to be communicated between the input-output unit and the central control unit. The system also includes a buffer memory in which transferred data are stored momentarily. Sets of data transfer control information from the central control unit are written in a control register. A microprocessor provides direct memory access control for data written in the control register to achieve data transfer control relative to the buffer. The microprocessor executes a predetermined microprogram for starting and finishing operations of the input and output unit control circuit through which the inputoutput unit is accessed for data transfer.