Oscillator and electronic apparatus using the same

An oscillator operated with an external power source or an external save power source used at a power-off time of the external power source, comprising:

• a clock signal generation unit generating and outputting clock signals having predetermined frequencies;
• a power-on detection unit detecting a power-on event of the external power source and outputting power-on detection signals;
• a power-off detection unit detecting a power-off event of the external power source and outputting power-off detection signals;
• storage storing accumulated running time up to a power-on time of the external power source;
• a running time count unit setting the accumulated running time, inputting the clock signals from the clock signal generation unit, and further accumulating the running time from a time of the power-on detection signals being input to a time of the power-off detection signals being input;
• and
• a control unit reading the accumulated running time from the storage at the time of the power-on detection signals being input to set the running time count unit with the read accumulated running time, reading a new accumulated running time counted by the running time count unit at the time of the power-off detection signals being input, and storing the new accumulated running time in the storage.