| 摘要 |
<p>PURPOSE:To prevent a runaway of a device to be controlled, by detecting a fact that a scanning pulse for selecting desired information to be set has stopped, and resetting an operation of a system. CONSTITUTION:A microcomputer 11 controls a motor, etc. in accordance with a program, and has a resetting circuit and a key recognizing function. The key recognizing function recognizes a matrix keyboard 12 by a key scanning pulse. The resetting circuit has time constant circuits 14, 17, respectively, together with the first and the second retriggable monostable multivibrators 13, 16, and it is connected to a reset terminal R of the microcomputer 11 through an OR gate circuit 15. Therefore, when a scanning pulse (g) stops, the first multivibrator 13 is not started, and an output signal (c) is inverted. Also, the second multivibrator 16 also inverts its output signal (d), and cuts off a voltage supply to the time constant circuit 17. As a result, a reset signal (f) which has been delayed by a prescribed period is outputted from the OR gate circuit 15.</p> |
