| 摘要 |
PURPOSE: To surely restore data destroyed caused by the turning-off of a power supply by minimizing the number of the data region of an EEPROM required for one measuring item to reduce the rewriting time of data in the data region. CONSTITUTION: An EEPROM comprises three data regions M1, M2, M3, and all of them are brought into the erase state 'FFFF' in the initial state (0 cycle) and the data regions M1, M2, M3 are sequentially counted down for every minimum time unit (cycle) required for the measuring item. The rewriting of data from '1' to '0' can be performed for every individual element (every cell) in the countdown, and since it is unnecessary to erase the whole, the processing time required for rewriting can be reduced. Even when the data of one data region is brought into the abnormal condition, the data can be surely restored by comparing the data with the count value of the other two data regions.
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