| 摘要 |
<p>PROBLEM TO BE SOLVED: To operate a semiconductor integrated circuit stably at a high speed by automatically setting frequencies of a clock signal corresponding to various states such as use conditions. SOLUTION: A CPU 13 reads and writes specific data of about one byte in and out of specific memory addresses of a RAM 4 which are electrically connected by the wiring pattern of a printed wiring board at constant intervals of time to judge whether or not the data can accurately be read and written, and increases the frequency of a clock signal when the data can accurately be read and written and supplies it to the semiconductor integrated circuit, but when not, a clock signal generation part 5 generates a clock signal of low frequency and automatically generates and supplies a clock signal of the highest frequency meeting the use conditions to the semiconductor integrated circuit device 3.</p> |
