| 摘要 |
PROBLEM TO BE SOLVED: To prevent important data from being lost when any abnormality is caused in a device. SOLUTION: The important data to be backed up are copied from an external RAM into a SRAM 142. When it is necessitated that the important data is written in before the completion of copy, the data are copied again from the beginning. Further, data are periodically copied from the SRAM 142 to a non- volatile memory 150 through a SRAM 148. In the case of restart processing, the power supply state signal of a voltage detector 144 is checked, and when a battery 142 is consumed, the data backed up to the non-volatile memory 150 are copied to the source address of the external RAM, but when the battery is not consumed, the data stored in the SRAM 142 are copied thereto. |
