Non-volatile memory control method
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsAkio Takeuchi, Shigekazu Kogita, Kazuya Iwata
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Abstract
A control method of nonvolatile memory, wherein it does not happen that data which ought to have been erased are not erased or data which ought to have been written are lost even in the case where forced interruption takes place due to shutdown of power source for memory device, reset command or the like, is provided. When data are written in a last page of a block, the block is validated by setting the block data validation flag provided in the redundant area of the last page of the block 0 (valid). Furthermore, by providing a counter for judging new or old, data can be protected even in the case where the above-mentioned solution means cannot respond to.
Claims6
A control method of a nonvolatile memory having a plural number of blocks, wherein
- said block has a plural number of pages,
- said page has data area for writing data and redundant area,
- said redundant area of initial said page of said block has a block data invalidation flag indicating whether said data written in the block are invalid or not and indicating that said data are not invalid at the state that the nonvolatile memory is erased, and
- said redundant area of last said page of said block has a block data validation flag indicating whether said data written in the block are valid or not and indicating that said data are not valid at the state that the nonvolatile memory is erased,
- having:
- a data writing step of writing data in said data area;
- and
- a validation step of making said block data validation flag of said block having said data area in which said data are written to indicate that said data are valid.
A nonvolatile memory characterized in having a plural number of blocks, wherein
- said block has a plural number of pages;
- said page has data area for writing data and redundant area;
- said redundant area of initial said page of said block has a block data invalidation flag indicating whether said data written in the block are invalid or not and indicating that said data are not invalid at the state that the nonvolatile memory is erased;
- said redundant area of last said page of said block has a block data invalidation flag indicating whether said data written in the block are valid or not and indicating that said data are not valid at the state that the nonvolatile memory is erased;
- and
- the block data validation flag of at least one said block indicates that said data are valid.
Dependencies are inferred from the claim text.