| 摘要 |
<p>PURPOSE:To make rapidness and long term retentivity compatible by providing a plurality of memory blocks, and incorporating both rapid writing and long term data retentivity in the blocks. CONSTITUTION:The writing voltage VPP1 of a memory block 1 is set to a high potential capable of writing at a high speed, and external data are written in a memory cell array through a transfer block 3. Then, data read from the block 1 by using the block 3 are written in the memory cell array 21 of a memory block 2. The writing voltage at this time is a voltage VPP2 lower than the absolute value of the VPP1. Thus, a high speed writing is conducted, and data can be retained for a long period.</p> |
