| 摘要 |
PURPOSE:To continue an execution of a program by a simple circuit constitution by storing information required for continuing an execution of a program, in a memory backed up by a battery, and thereafter, stopping a power supply to a processor. CONSTITUTION:When a power source switch is turned off in a state that a CPU1 is not in a power save mode, an output of a high level of a power save terminal PS of the CPU1 is provided to an OR gate 4, the OR gate 4 maintains a high level, and a power supply to the CPU1 from a power source circuit 5 is not stopped. When this state continues for a prescribed time, the CPU1 transfers and stores the contents of a program counter PC, a stack pointer SP and a register RG in an RAM2 to which power is supplied by a battery 3, and thereafter, becomes a power save mode. Therefore, both input signals to both input terminals of the OR gate 4 become a low level, its output signal also becomes a low level, and a power supply to the CPU1, etc. from the power source circuit 5 is stopped.
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