Patent ID: 7613043

Claim:
A method for adjusting for sag in stored data values, the method comprising: applying charge to a plurality of memory cells, each memory cell charged to a target voltage corresponding to a data value, the plurality of memory cells comprising a reference cell, the reference cell charged to a predetermined voltage; detecting a voltage level in the reference cell; detecting voltage levels from a group of memory cells; performing an adjustment based upon the difference between the detected voltage level in the reference cell and the predetermined voltage, wherein the adjustment is an adjustment to a correction function, the correction function converting detected voltage levels into corrected voltage levels; for each detected voltage level from the group of memory cells, receiving at a data processor a digital signal representing the detected voltage level; applying the adjusted correction function in the data processor to convert the received digital signals representing the detected voltage levels from the group of memory cells into corrected digital signals representing corrected voltage levels; and converting the corrected digital signals representing the corrected voltage levels into digital data values selected from a group of possible data values based upon a selection criteria.