| 摘要 |
PURPOSE:To facilitate the data processing and to improve the operability with a state transition detector by grasping the state of an I/O device at all times at the side of the data processor. CONSTITUTION:A periodical interruption means 101 produces interruptions for each fixed cycle and starts a state monitor means 102. Then the means 102 extracts the state information on an I/O device 20 to a state information register 104 from an I/O data port 103 via an interface cable 11. The state information on the register 104 is compared with the state information stored in a state information memory 106 through a comparator 105. Thus the signal is supplied to a state transition interruption means 107 and the state information on the register 104 is stored in the memory 106. Therefore the programs working through a logic part 110 and a main memory 120 can grasp the latest state of the device 20 from the contents of the memory 106.
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