| 摘要 |
<p>PURPOSE:To conduct reset without damaging an internal circuit by installing a resistor between an internal reset circuit and a power-ON reset circuit and preventing addition to an output from the internal reset circuit of an output from the power-ON reset circuit. CONSTITUTION:A resistor R2 is mounted between an internal reset circuit 20 and an output from a power-ON reset circuit. When a power supply is turned ON and voltage at the reset terminal of a CPU 30 is increased by a time constant in the power-ON reset circuit and exceeds the threshold voltage of reset, the CPU 30 starts its operation. When the power supply is instantaneously interrupted and a watched timer is made to overflow, the flowing of large currents through the internal reset circuit 20 is prevented by a voltage drop by the resistor R2. Accordingly, damage to the internal reset circuit 20 is prevented.</p> |
