| 摘要 |
PURPOSE:To prevent previously the control from being instable by resetting a microcomputer when the level of supply voltage is lowered as well as when a runaway of a program is detected. CONSTITUTION:A voltage-responding reset circuit 23 containing a voltage lowering detection circuit 25 to detect that the voltage level of an electric source line 22 connected to a battery BT is lowered under a fixed value is provided to set a transistor 32 on to reset a microcomputer 10 when an output is issued from the circuit 23. Meanwhile, a pulse processing circuit 33 is provided to decide whether an information pulse PT of the microcomputer 10 is generated with a fixed regularity or not and reset the microcomputer 10 in case of NO. This processing circuit 33 is equipped with a counter 36 which will be given an overflow state when the information pulse PT is irregular for resetting the microcomputer 10 via a single stable multivibrator 28 by the output thereof. |
