| 摘要 |
PROBLEM TO BE SOLVED: To achieve certain recovery from abnormality of a microprocessor even when diagnosing a watch dog timer during running of the microprocessor.SOLUTION: A microprocessor external monitoring circuit outputs a clear signal input from a microprocessor to a watch dog timer switched from multiple watch dog timers by input switching means. The watch dog timer receiving no input of the clear signal generates a reset signal; however, first output means prevents the reset signal from being output to the microprocessor. Then, second output means outputs the reset signal to the microprocessor as a check signal for notifying the microprocessor of normal running of the watch dog timer. The microprocessor switches and diagnoses a watch dog timer to be diagnosed, by switching the input switching means. |
