| 摘要 |
In a non-volatile memory that reads a binary value from a storage cell by comparing the voltage level of a stored charge in that cell against a reference voltage, the accumulated errors in a range of memory locations may be analyzed to determined if there are more errors in one direction than the other (for example, more 0-to-1 errors than 1-to-0 errors). If so, the reference voltage may be adjusted up or down so that subsequent reads from that range may produce approximately the same number of errors in each direction. For multiple-bits-per-cell memories, where there are multiple reference voltages for each cell, each reference voltage may be adjusted separately by keeping track of the errors related to that particular threshold.
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