| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability in a reset operation by permitting the power source of buffer circuits to be common with the power source to be given to a microcomputer. SOLUTION: A switch 13 is provided in the route of a reference voltage to be given to a regulator circuit 9 for supplying power to the microcomputer 16, it is disconnected unless the voltage is sufficient for the operation and power is not given to the microcomputer 16. Besides, the voltage being more than a power source terminal is not obtained even in another terminal of the microcomputer 16 by connecting the same power source being the same as that of the microcomputer 16 to the buffer circuits 15a-15d. Moreover, a change-over operation is executed by logic which occurs in an AND circuit 14 in the switch 13. Thus, the power of a common line with the microcomputer 16 is given to the circuits 15a-15d and the power is surely disconnected unless the operation of a logical circuit is guaranteed. Therefore, inconvenience that resetting is errorneously released while the voltage is low and also the voltage being more than the power source terminal is supplied to the respective terminals of the microcomputer 16 is eliminated. |
