| 摘要 |
PURPOSE:To prevent malfunction due to a low voltage from occurring by detecting voltage drop in a battery, and automatically operating the reset circuit of a CPU when the voltage drops to a value lower than a prescribed value. CONSTITUTION:Since an IC 32 for holding outputs a high level when the voltage VDD of the battery shows the voltage higher than a hold voltage set in advance, the hold input terminal 22 of the CPU 20 is set at the high level, thereby, the CPU 20 can be operated normally. In such a case, when the voltage VDD of the battery decreases gradually, the IC 32 for holding detects the voltage set in advance, then, the IC outputs a low level. Since such low level sets the hold input terminal 22 of the CPU 20 at the low level, the CPU 20 advances to a hold state. Therefore, the CPU 20 backs up only a RAM, which minimizes the consumption of the power source by stopping all other operations. The set is brought back to the master machine to charge the battery, or the battery is exchanged. |
