CPC G11C 16/26 (2013.01) [G11C 16/3495 (2013.01); G11C 16/0483 (2013.01)] | 20 Claims |
1. An operation method of a controller which is configured to control a nonvolatile memory device, the method comprising:
receiving cell counting data associated with selected memory cells included in the nonvolatile memory device from the nonvolatile memory device, wherein the receiving of the cell counting data associated with the selected memory cells included in the nonvolatile memory device from the nonvolatile memory device includes:
transmitting a first cell-counting command to the nonvolatile memory device; and
receiving the cell counting data from the nonvolatile memory device;
adjusting operation parameters of the nonvolatile memory device based on the cell counting data;
performing a valley search operation for the selected memory cells based on the adjusted operation parameters; and
performing a read operation for the selected memory cells based on a result of the valley search operation.
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