| 摘要 |
The rewriting of one access unit (a page) of data stored in non-volatile memory 1 is executed by erase and write cycles, data being protected from loss in the event of an interruption in electric power.
<??>When rewriting into second data the first data which is stored in a data storage area 10a of the non-volatile memory, either the first or the second data is stored in a save area 11 of the non-volatile memory 1, and the first data in the data storage area 10a is erased only after data has been entered in the save area 11. Thereafter the writing of the second data in the non-volatile memory, into data storage area 10a, and, if necessary a previously blank data storage area 10x, takes place to complete rewrite operation.
<??>The rewriting takes place under control of a processor 4. A memory 2 holds the first and second data temporarily during the rewrite operation. Read and write of non-volatile memory 1 and temporary storage memory 2 are effected by a memory controller 6 and a direct memory access device 7. |
