PURPOSE: To cope with both of the low power consumption of a controller and the the improvement of a function for speeding up an operation start by enabling the controller to select whether a power source circuit is stopped or the output step of a clock is stopped.

CONSTITUTION: A source oscillation circuit part 1 oscillates the clock of a controller, and an output step stop circuit part 2 transmits the clock oscillated and outputted from the source oscillation circuit part 1 to the outside and stops the clock. A source oscillation stop circuit part 3 oscillates the source oscillation circuit part 1, oscillates and stops the part 1, and a reference voltage part 4 outputs two kinds of reference voltage or first reference voltage VREF1 and second reference voltage VREF2. By control input voltage VIN, the source oscillation circuit part 1 is stopped. Or the source oscillation circuit part 1 is made to operate and an oscillation signal is not made to be outputted from the output step stop circuit 2. Or three kinds of controls outputting the oscillation signals of the source oscillation circuit part 1 can be performed. Therefore, the controller is made adaptable to the both of emphasizing the saving of power consumption and the function for speeding up the start of the clock.