CLOCK SIGNAL CONTROL CIRCUIT

摘要

PROBLEM TO BE SOLVED: To prevent malfunction of a system due to an unstable clock signal caused at rising of a power supply in an electronic device such as a portable terminal. SOLUTION: The control circuit is provided with a pulse rate detection circuit 102 that detects it that an oscillator is stably oscillated, a clock supply selection circuit 103 that decides whether or not a clock signal is supplied to a clock operation circuit 104 based on an output of the detection circuit 102. Thus, the circuit 103 supplies the clock signal to the clock operation circuit 104 only when the pulse rate detection circuit 102 permits the supply of the clock signal.