| 摘要 |
PURPOSE:To prevent the destruction of data in course of read, by holding the set timing of status information when a set request is issued from an input/output device during the status information read of a main processing device and by setting information from the input/output device after the read. CONSTITUTION:An input/output control device 2 is provided between an input/ output device 1 and a CPU3 as a main processing device including a memory 4, and status data 7 from the device 1 is set to a status register 9. Status information is read through a driver 11 at a prescribed timing by the CPU3. If a set request of status data 7 is issued from the device 1 while the CPU3 reads status information on the register 7, the set timing of a status set signal 6 is held temporarily in a data protecting circuit 8, and a set pulse 19 is sent to the register 9 from the circuit 8 after the completion of the read due to a read indication signal 10, and status data 7 is set to the register 9, thus preventing the destruction of data in course of read. |
