| 摘要 |
PROBLEM TO BE SOLVED: To perform a self-test of operations of WDT (watchdog timer) for monitoring CPU (Central Processing Unit) runaways during the operation of a CPU. SOLUTION: A CPU 101 supplies a first and a second watchdog clear signals WD1 and WD2 to a first and a second WDT1 and WDT2 and resets the CPU 101 via a logic coupling element 122, when both of the clear the signals WD1 and WD2. The CPU 101 has an abnormality diagnosing means for diagnosing the reactions of the WDT1 through a monitor signal MN1, by stopping intentionally the WD1 and diagnosing reactions of the WDT2 through a monitor signal MN2 by stopping the WD2 and diagnoses the WDT1 and WDT2, without having to stop the CPU 1. |
