| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To control so that data stored in a page buffer circuit and needless for writing is not written in a memory cell without complicating the writing control by a WSM circuit. <P>SOLUTION: This device is provided with a mask circuit 170 in which at least one part of data read from a page buffer circuit 120 is replaced by data for which writing operation is not performed. In a flash memory controllable by a plurality of data bus width, a multi-value flash memory provided with a page mode reading function, or the like, when data needless for writing in a memory cell is read from the page buffer circuit 120, the read data is replaced in the mask circuit 170 by data in which writing operation is not performed, thus, the data is prevented from being written into a memory cell. To judge necessity of mask, discrimination by comparing magnitude of addresses, discrimination of coincidence of addresses, the number of written data, or the like are utilized. <P>COPYRIGHT: (C)2004,JPO</p> |
