| 摘要 |
PURPOSE:To prevent the malfunction of a device to be connected at the destination of an interface signal by duplexing the interface signal, checking whether one signal is same as the other signal or not and using one signal for diagnosis. CONSTITUTION:An interface signal IF is set to a first flip-flop 10 by a microinstruction MI and an interface signal IF' is set to a second flip-flop 20. A check circuit 30 always decides and monitors whether the interface signals IF and IF' are same or not. In such a case, a diagnostic operation by a shift path SPi is executed by the second flip-flop 20 and the diagnostic operation of the first flip-flop 10 is indirectly executed. Thus, the interface signal of the first flip-flop is not changed and no influence exerts upon the device to be connected at the destination of the interface signal IF. |
