MEMORY CONTROLLER AND SEMICONDUCTOR MEMORY APPARATUS
First Claim
1. A memory controller configured to control an error correction for a flash memory section, comprising:
- an error correction number correspondence table that stores an error threshold level in correspondence with an error correction number when performing encoding processing of data stored in the flash memory section, the error correction number capable of being increased or decreased, and the flash memory section being composed of a plurality of memory cells that are each classifiable into any one of a plurality of set units;
an error threshold level storage section that stores an error threshold level for each of the set units;
an uncorrected number measurement section that measures an uncorrected number of an error correction for each of the set units;
an error threshold level modification section that, each time the uncorrected number of a certain set unit exceeds a predetermined number, modifies the error threshold level of the relevant set unit that is stored in the error threshold level storage section to a new error threshold level;
an encoder that performs the encoding processing with the error correction number that is based on the error threshold level stored in the error threshold level storage section and the error correction number correspondence table; and
a decoder that performs decoding processing of data that is stored in the flash memory section.
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Accused Products
Abstract
A memory controller that has an error correction number correspondence table that stores an error threshold level in correspondence with an error correction number; an error threshold level storage section that stores an error threshold level for each block; an uncorrected number measurement section that measures an uncorrected number of an error correction for each block; an error threshold level modification section that, each time an uncorrected number of a certain block exceeds a predetermined number, modifies the error threshold level of the block; an encoder that performs encoding processing of data stored in memory cells belonging to each block with an error correction number that is based on an error threshold level and the error correction number correspondence table; and a decoder that performs decoding processing of data.
45 Citations
17 Claims
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1. A memory controller configured to control an error correction for a flash memory section, comprising:
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an error correction number correspondence table that stores an error threshold level in correspondence with an error correction number when performing encoding processing of data stored in the flash memory section, the error correction number capable of being increased or decreased, and the flash memory section being composed of a plurality of memory cells that are each classifiable into any one of a plurality of set units; an error threshold level storage section that stores an error threshold level for each of the set units; an uncorrected number measurement section that measures an uncorrected number of an error correction for each of the set units; an error threshold level modification section that, each time the uncorrected number of a certain set unit exceeds a predetermined number, modifies the error threshold level of the relevant set unit that is stored in the error threshold level storage section to a new error threshold level; an encoder that performs the encoding processing with the error correction number that is based on the error threshold level stored in the error threshold level storage section and the error correction number correspondence table; and a decoder that performs decoding processing of data that is stored in the flash memory section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor memory apparatus, comprising:
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a flash memory section composed of a plurality of memory cells that are each classifiable into any one of a plurality of set units; an error correction number correspondence table that stores an error threshold level in correspondence with an error correction number of a memory controller when performing encoding processing of data stored in the flash memory section, the error correction number capable of being increased or decreased; an error threshold level storage section that stores an error threshold level for each of the set units; an uncorrected number measurement section that measures an uncorrected number of an error correction for each of the set units; an error threshold level modification section that, each time the uncorrected number of a certain set unit exceeds a predetermined number, modifies the error threshold level of the relevant set unit that is stored in the error threshold level storage section to a new error threshold level; an encoder that performs the encoding processing with the error correction number that is based on the error threshold level stored in the error threshold level storage section and the error correction number correspondence table; and a decoder that performs decoding processing of data that is stored in the flash memory section. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A semiconductor memory apparatus, comprising:
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a NAND-type flash memory section composed of a plurality of memory cells classifiable into any block that is an erase unit; an error correction number correspondence table that stores an error threshold level in correspondence with an error correction number of a memory controller when performing encoding processing of data stored in the flash memory section, the error correction number capable of being increased or decreased by the block; an error threshold level storage section that stores an error threshold level for each of the blocks; an uncorrected number measurement section that measures an uncorrected number of an error correction for each of the blocks; an error threshold level modification section that, each time the uncorrected number of a certain block exceeds a predetermined number, modifies an error threshold level of the block that is stored in the error threshold level storage section to a new error threshold level; an encoder that performs the encoding processing with the error correction number that is based on the error threshold level stored in the error threshold level storage section and the error correction number correspondence table; and a decoder that performs decoding processing of data that is stored in the flash memory section.
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Specification