| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve reliability of a storage device including a nonvolatile memory. <P>SOLUTION: For instance, a normal memory area NML_AR and a checking memory area CHK_AR are set, and a writing is carried out for the CHK_AR by writing voltages V1-Vn lower than a writing voltage V0 of the NML_AR. By this procedure, a data holding period of a memory cell in the CHK_AR becomes shorter as compared with that of the memory cell in the NML_AR, therefore, by determinating the existence of inversion of storage data of the CHK_AR by a determination circuit JGE, the countermeasure for error can be carried out before the storage data of the NML_AR are inverted to become an error. <P>COPYRIGHT: (C)2008,JPO&INPIT |
