| CPC G11C 29/52 (2013.01) [G11C 7/1039 (2013.01); G11C 29/50004 (2013.01)] | 19 Claims |
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1. A method, comprising:
reading data stored in a non-volatile storage device using a group of soft read reference voltages;
decoding the data read from the non-volatile storage device in a soft decoding process;
obtaining a number of ones and a number of zeros for each zone of a plurality of zones delineated by the group of soft read reference voltages;
determining that a soft read reference voltage of the group of soft read reference voltages is a first boundary of a first zone in which the number of ones is greater than the number of zeros and a second boundary of a second zone in which the number of ones is less than the number of zeros; and
setting the soft read reference voltage adjusted by an adjustment as an optimal read reference voltage for future read operations, the adjustment being obtained based on a first comparison result of the number of ones compared to the number of zeros in the first zone and a second comparison result of the number of ones compared to the number of zeros in the second zone.
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