| 摘要 |
<P>PROBLEM TO BE SOLVED: To more reduce erase operation of data which is needed accompanying potential fluctuation of a cell. <P>SOLUTION: A memory system includes a plurality of nonvolatile memory cells MC connected electrically to a common word line WL. Each memory cell stores a plurality of data corresponding to a plurality of potential ranks. Further the memory system measures a potential of the memory cell for each potential rank and includes a control part 14 changing a lower limit and upper limit of each potential rank based on this measurement result. <P>COPYRIGHT: (C)2011,JPO&INPIT |
