DEVICE FOR MONITORING INTERNAL STATE AND METHOD FOR DETECTING NONCOINCIDENCE

摘要

PURPOSE:To rapidly detect a signal change without depending upon the processing capacity of a processor and increasing storage capacity by making it possible to detect the state of a data change simultaneously with the writing of data in a storage means. CONSTITUTION:A control circuit 18 for controlling the reading/writing of data outputted from an input signal synchronizing memory 12 and an output signal holding memory 15 is connected to the memories 12, 15 to transfer the result of rudder processing to the memory 15 based on a command outputted from a processor 13. A reading data comparator 19 inputs data obtained before and after transferring data between a data bus 14 and the memory 12 or between the data bus 14 and the memory 15 at a prescribed timing and rewriting the transferred data and detects the noncoincidence of these data. Since the change of data is detected simultaneously with the writing of data in the storage means 12, 15, the state of a signal change can be rapidly detected without increasing the load of software processing or the contents of the memories.