| 摘要 |
PURPOSE:To set the most suitable time set value, by holding the maximum value of the counted values of a watchdog timer in a register and making it possible to read out the counted value and the maximum value of the watchdog timer which change every moment. CONSTITUTION:Detection of a program running condition is performed in parallel with the supervisory operation of the program running condition. A comparison/control circuit 5 reads out the content of a watchdog timer 1 and content of a maximum value holding register 2 at a prescribed period and compares both values. When the counted value of the watchdog timer 1 is larger than the other, the circuit 5 holds the maximum value holding register 2 in the counted value by controlling a gate 6. When the counted value is smaller than the other, on the contrary, the gate 6 is not opened and the register 2 holds the original its content. Since the record of the watchdog timer 1 which changes every moment can be taken, a time set value can be corrected to the most suitable value base on the record. |
