| 摘要 |
PURPOSE:To ensure the content of a memory even when power source is turned off during rewriting action by discriminating that abnormal content is written in the memory if the value is not a normal value when data are read out and outputting an initially set value in place of the value. CONSTITUTION:When power source is turned off by a power source switch 7 during rewriting action, especially when interrupted during erasing action, all data bits making rewriting action at the same time are erased. Accordingly, when power source is turned on and the memory is read out, abnormal data are inputted to a D/A converter circuit 6. Therefore, a predetermined bit for discrimination is put in data bits that make rewriting action at the same time, and the content of memory data is discriminated whether it is normal or abnormal by detecting this bit for discriminaton. When it is found to be abnormal data, for instance, the data for discrimination is 0 instead of 1, the data is discriminated to be abnormal. A value that offers no problem in normal state of using is made an initial set value and made to become this set value automatically. |
