公开(公告)号：US5390130A

公开(公告)日：1995-02-14

申请号：US793614

申请日：1991-11-18

申请人： Akira Watanabe ,  Atsushi Maruyama ,  Touko Kobayashi ,  Azuma Miyazawa

发明人： Akira Watanabe ,  Atsushi Maruyama ,  Touko Kobayashi ,  Azuma Miyazawa

IPC分类号： G03B7/091 ,  G03B7/26 ,  G03B17/00 ,  G06F1/24 ,  G08B21/00 ,  G03B17/18

CPC分类号： G03B7/26

摘要： A CPU checks whether a content of a battery insertion detecting RAM has a predetermined bit configuration and whether a flag during battery check is set after power on reset. If neither the RAM has the bit configuration nor the flag is set, the flag is set and then a dummy current is caused to flow into a dummy load. When power consumption is high, the power supply voltage greatly drops within a predetermined period of time after the dummy load is turned on and therefore the voltage sensing IC detects the voltage drop and the CPU is reset. Since the CPU initializes all ports if it is subjected to hard reset, the current is stopped to flow into the dummy load and the power supply voltage is recovered. After the hard reset, the CPU checks the content of the RAM and the flag. Since the flag continues to be set, the CPU determines that the battery runs down and performs a battery run-down operation. When the battery is loaded, the RAM usually has a predetermined bit configuration. If the content of the RAM is checked, it is possible for the CPU to determine whether the hard reset is performed by loading the battery or it is performed since the voltage sensing IC detects a drop in the battery voltage during the battery check.

摘要翻译： CPU检查电池插入检测RAM的内容是否具有预定的位配置，以及在上电复位后是否设置电池检查期间的标志。 如果RAM都没有位配置，也没有设置标志，则设置标志，然后使虚拟电流流入虚拟负载。 当功耗高时，在虚拟负载接通之后的预定时间段内电源电压大大下降，因此电压感测IC检测到电压降并且CPU被复位。 由于CPU在进行硬复位时初始化所有端口，所以停止电流流入虚拟负载并恢复供电电压。 硬复位后，CPU检查RAM的内容和标志。 由于标志继续设置，CPU会确定电池电量不足，并执行电池电量耗尽操作。 当电池加载时，RAM通常具有预定的位配置。 如果检查RAM的内容，则CPU可以通过加载电池来确定是否执行硬复位，或者由于电压检测IC在电池检查期间检测到电池电压的下降而执行。