| 摘要 |
PROBLEM TO BE SOLVED: To reduce unnecessary electromagnetic radiation noise due to an operation clock signal generated by an oscillator circuit. SOLUTION: In a semiconductor integrated circuit, random number data output by a random number generation circuit 10 is stored in a frequency variable data register 12. The data stored in the frequency variable data register 12 is replaced by random number data sequentially generated by the random number generation circuit 10. An oscillator circuit 13 is a circuit generating a clock signal, and the clock signal is supplied as an operation clock signal to an internal circuit 14 through an unillustrated operation clock signal generation circuit. The frequency of the clock signal from the oscillator circuit 13 is variably controlled in response to the random number data stored in the frequency variable data register 12. A frequency variable range control register 15 which stores control data for controlling the range of the frequency variably controlled in response to the random number data stored in the frequency variable data register 12 is further provided. COPYRIGHT: (C)2009,JPO&INPIT |
