| 摘要 |
PURPOSE:To prevent data from being dissipated and disable to be restored due to power interruption, etc., when the data stored in nonvolatile memory on which overwrite is disabled is updated. CONSTITUTION:Plural data blocks 7 consisting of plural data areas 8 in which the same data is stored corresponding to each datum are formed in the nonvolatile memory 4, and the data stored in one data area in the data block 7 in accordance with update request data selected by prescribed procedure is read out corresponding to a data update request, and it is written on volatile memory 3, and the data stored in the volatile memory 3 is updated, and a storage content in a selected data area 8 is cleared, and the data after update is written on a cleared data area 8, and after that, the contents of another unselected data areas 8 are cleared, then, the data after update is written on each cleared data area 8. |
