| 摘要 |
<p>PURPOSE:To enable it to detect trouble in a microcomputer by installing a watchdog timer circuit or the like which outputs a reset signal to each microcomputer when a periodic abnormal state has continued as long as more than the specified time, in a car-mounted controller using two-microcomputers. CONSTITUTION:Two microcomputers 1, 2 of a car-mounted controller the microcomputer 1 at the first of an operating period and the microcomputer 2 at the timing different from the former generate each of one-shot output signals (a), (b) as a watchdog pulse respectively. Then, these output signals (a), (b) are inputted into two reset terminals S, R of an FF circuit 3 through which each operating period of the microcomputers 1, 2 is converted into a rectangular wave, making it output a signal (c). This signal (c) is inputted into a period abnormal judging circuit 4, and when an output period of this signal (c) is not within the specified range, it is so judged as something wrong, and when this abnormal state has continued as long as more than the specified time, a reset signal is generated to each of these microcomputers 1, 2 from the watchdog timer circuit 22.</p> |
