| 摘要 |
<p>PURPOSE:To prevent data from being erroneously written in a specified memory area to be used in place of a ROM by the malfunction of a CPU or the like by preventing data signals from being outputted by a write circuit receiving a write enable/disable signal when storing write inhibit information in a write enable/disable information memory cell. CONSTITUTION:This device is provided with a write enable/disable information memory cell 22 to store write enable information or write inhibit information concerning respective word lines 11, and write enable/disable judging means 18 connected to the write enable/disable information memory cell 22 and a write circuit 25. The write enable/disable judging means 18 outputs a write enable/disable signal through a write enable/disable signal line 23 to a write circuit 29 corresponding to the information stored in the write enable/disable information memory cell 22 concerning the word line 11 selected by a row decoder 13. The write circuit 29 stops the output of data signals corresponding to the write enable/disable signal.</p> |
