Patent ID: 8738974
Filing Date: 2014-05-27
Classification: G06F,G11C

Abstract:
1. A memory controller for writing and reading data to and from a nonvolatile memory, wherein the nonvolatile memory has a plurality of memory cell blocks, each memory cell block includes a plurality of multi-level cells each capable of storing 2-bit data, a lower page and an upper page are respectively allocated to the 2 bits of the multi-level cell, the memory controller sequentially writes the data to the memory cells starting from the lower page of the multi-level cell, and comprises a backup unit, and when a write command is received from the outside of the memory controller, in a case where (i) a data write destination of data to be written is the upper page of the multi-level cell and (ii) data is already written in the lower page of the multi-level cell, the backup unit backs up the data that is already written in the lower page of the multi-level cell to a nonvolatile storable backup region before writing the data to be written to the upper page of the multi-level cell.