| 摘要 |
PROBLEM TO BE SOLVED: To perform a failure diagnosis of a filter circuit part of a watchdog circuit by outputting a pulse of a higher frequency than that of a pulse outputted in a watchdog pulse output control step between an initialization step and the watchdog pulse output control step. SOLUTION: A step (ST 200) for reversing a logic of an output terminal of a microcomputer outputting a watchdog pulse is interposed between a step (ST 140) judging whether a reset signal is supplied or not and a step (ST 150) judging whether a monitoring timer is up or not. When a diagnosis of a watchdog circuit is performed by operating the monitoring timer (ST 130) by this interposition, the three steps are circulated. Therefore, the watchdog pulse outputted in the ST 200 becomes short in period, that is, the pulse becomes higher in frequency and the pulse deviates from a passing frequency band of a low-pass filter of the watchdog circuit. |
