CPC G11C 29/42 (2013.01) [G11C 16/0433 (2013.01); G11C 16/08 (2013.01); G11C 16/24 (2013.01); G11C 16/26 (2013.01); G11C 16/3495 (2013.01); G11C 29/4401 (2013.01)] | 20 Claims |
1. A reading method of a nonvolatile memory device, the reading method comprising:
receiving, from a controller, a first read command for reading first page data, corresponding to a wordline;
performing a first page on-chip valley search (OVS) operation in response to the first read command;
outputting the first page data based on the first page OVS operation to the controller;
outputting detection information, indicating detection cases for at least two states of the first page OVS operation, to the controller in response to a command from the controller;
receiving, from the controller, a second read command for reading second page data, corresponding to the wordline;
performing a second page read operation in response to the second read command; and
outputting the second page data, based on the second page read operation, to the controller,
wherein a read level of at least one state, different from the at least two states, is changed to a changed read level using the detection information, and
the second page read operation is performed based on the changed read level.
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