| 摘要 |
<p>PURPOSE: A nonvolatile semiconductor memory device is provided to improve the confidentiality of data by rewriting data to a memory cell array, maintaining the data, and reading the date. CONSTITUTION: A memory cell transits first and second data memory status by an electrical rewriting. A memory cell array(1) comprises a permanent memory cell fixed with a third data memory state read as the same logic level data as the first memory state. A control circuit(2) rewrites data to a memory cell array, maintain data, and reads data. The data written in the memory cell array uses at least one memory cell and one permanent memory cell. The data written in the memory cell array is written in a specific confidential data region(1b) of the memory cell array.</p> |
