| 摘要 |
PURPOSE:To reduce a refreshment overhead by setting a refreshment period time in a timer counter and outputting a refresh request signal from a refreshment control part at every interval of this set period time. CONSTITUTION:A temperature detecting means 11 reads ambient temperature and outputs an analog value TA based upon the temperature in a step S1. The analog value is converted into a digital value TD by an A/D converter 12 in a step S2. This digital value TD is converted by a temperature/time conversion part 14 into a refreshment period time RT in a step S3, and the time RT is stored in the timer counter 15 in a step S4. The correspondence between said digital value TD and refreshment period time TA is set previously. The refreshment period time is set on the basis of the ambient temperature in the steps S1-S4 and the refreshment period is counted on the basis of the set time in S5 and S6 to perform refreshing operation. |
