| 摘要 |
<P>PROBLEM TO BE SOLVED: To correct the inexactitude of a timepiece caused by a difference in source voltage between when the timepiece is powered and when it is turned off for backup, using a timepiece function which provides time data using an external X' tal as a reference clock while switching power supplies between when it is operated and when it is backed up, such as an RTC macro with a built-in ASIC. <P>SOLUTION: The timepiece control circuit has a memory for storing time data read from an RTC and a time data updating means for writing into the memory the time data read from the RTC at regular intervals. When the circuit is powered again, the difference between the time data stored in the memory and the time data read from the RTC is calculated and the timepiece is corrected when the total of off time increases above a certain level. <P>COPYRIGHT: (C)2003,JPO |
