| 摘要 |
<p>PURPOSE:To exactly inform a low voltage alarm state of a user even when an MPU is set in a sleep state concerning a device driven by a battery. CONSTITUTION:This device is provided with an MPU 1 to generate a clock signal in the active state, to stop generating the clock signal in the sleep state and to turn to the sleep state when no key input exists for prescribed time, alarm detection circuit 5 to output an alarm signal by detecting that a battery voltage is lower than a prescribed value, and pseudo keying circuit 3 to turn an alarm signal (b) from the alarm detection circuit 5 to a pseudo signal a' equivalent to a key input signal (a) and to input it to the MPU 1. When the MPU 1 is set in the sleep state, it is turned to the active state by the pseudo signal a' from the pseudo keying circuit 3, the alarm signal (b) from the alarm detection circuit 5 is read based on the clock signal, and alarm information is displayed.</p> |
