| 摘要 |
PURPOSE: A reset circuit for preventing a hang-up is provided to reset a CPU of a hard disk drive automatically when a hang-up is generated in the CPU. CONSTITUTION: A power monitor circuit(10) generates and outputs a reset signal when a power source is inputted. A CPU(20) generally controls a hard disk drive. The CPU(20) is initialized by the reset signal. When a power source is inputted, a multivibrator(40,50) outputs an initial value for resetting the CPU(20). In a normal operation, the multivibrator(40,50) generates and output a pulse of a predetermined cycle in accordance with a logic level of a clock pulse being inputted from the CPU(20). An AND gate(30) performs an AND-gate of a signal being inputted from the power monitor circuit(10) and the multivibrator(40,50), respectively, and outputs the signal to a reset terminal of the CPU(20). A clear terminal of the multivibrator is connected to an access point of a resistance and a capacitor serially connected between an input power source side and a grounding side, and generates/outputs an initial signal of a predetermined level when a power source is inputted.
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