| 摘要 |
<p>PURPOSE:To obtain high reliability against artificial and systematical illegality by furthermore judging whether a storage element is a normal product or not in a control device for executing the monitoring of runaway by means of a watchdog timer circuit. CONSTITUTION:Immediately after the rising of the voltage of a power supply line VC, a CPU 10 executes an initial processing program and confirms an identification(ID) code stored in a prescribed area of a PROM 12 to judge whether the PROM 12 is a normal product or not. Power supply to the watchdog timer circuit 18 is delayed by the period of a time required for the judgement, so that the misrecognition of runaway can be prevented even if the CPU 10 does not reset the circuit 18. However runaway monitoring by the circuit 18 is executed similarly to a convensional method during the period that the CPU 10 executes processing based upon a control program.</p> |
