| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit (MCU) to be arranged in a device for electric tools which can set the count time with a watch dog timer according to processing contents of the control circuit.SOLUTION: In control circuits (MCU) 30 and 60 which control a device for an electric tool, e.g. an electric tool 10 or a battery pack 40, two watch dog timers WDT (1) and WDT (2) are provided. In executing a control program, the control circuits (MCU) reduce the count time of the WDT (1) by modifying the count time of at least the WDT (1) according to the contents of the program, e.g. presence or absence of writing into or deletion from non-volatile memory 69, when the processing time for clearing the WDT (1) and WDT (2) is short. The count time of the WDT (1) is longer than that of the WDT (2). |
