| 摘要 |
<p>Conventionally it is difficult to judge whether the error, if occurs during read of a nonvolatile memory, is accidental or is the one that may occur frequently due to degradation. Consequently the alternate operation is conducted frequently, and the alternate is used upper, thereby shortening the device life. In a semiconductor storage according to the invention, an alternate operation to be conducted after deducing the cause of the error in the data read out of a nonvolatile memory on the basis of the number of corrections made in the past when the error is corrected or a data refreshing operation is selected. If any error occurs, the data is corrected and rewritten, and thereby accidental error recurrence is prevented. Data judged to have a high error recurrence frequency on the basis of the record of the number of error corrections has a high possibility of containing an error due to degradation, and hence an alternate operation is conducted.</p> |
