MEMORY CONTROLLER, STORAGE DEVICE AND MEMORY CONTROL METHOD
First Claim
1. A memory controller configured to control nonvolatile memory including a memory cell in which data of K bits is storable in one memory cell, where K is an integer greater than or equal to two, a first bit of the data of K bits representing data of a first page and a second bit representing data of a second page, the memory controller comprising:
- an encoder configured to encode unit data to write in the first page to generate a parity;
a memory control unit configured to perform control to write the unit data and the parity in the nonvolatile memory at time of write in the first page, and to perform control to write the unit data in the nonvolatile memory at time of write in the second page;
a decoder configured to perform an error correction process using the unit data and the parity read out from the nonvolatile memory; and
a readout control unit configured to instruct the memory control unit to carry out readout using 2K−
1 first voltage values at time of readout from the first page and instruct the memory control unit to carry out readout using a second voltage values, which are different from the first voltage value and less in number than 2K−
1, at time of readout from the second page, and to select a bit value of the second page from a determination results of the bit value by the second voltage values based on the bit value of after the error correction of the first page;
wherein the memory control unit performs the readout from the nonvolatile memory based on an instruction from the readout control unit.
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Accused Products
Abstract
According to one embodiment, there is provided a memory controller that controls nonvolatile memory of K bits/cell, first and second bits of the K bits corresponding to first and second pages, the memory controller including an encoder configured to encode unit data to write in a first page to generate a parity; and a decoder configured to perform an error correction process using the readout unit data and the parity; where readout of the first page is carried out using 2K−1 first voltage values, readout of the second page is carried out using a second voltage value, which is less in number than 2K−1, and a bit value of the second page is selected based on a bit value of the first page of after the error correction.
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Citations
17 Claims
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1. A memory controller configured to control nonvolatile memory including a memory cell in which data of K bits is storable in one memory cell, where K is an integer greater than or equal to two, a first bit of the data of K bits representing data of a first page and a second bit representing data of a second page, the memory controller comprising:
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an encoder configured to encode unit data to write in the first page to generate a parity; a memory control unit configured to perform control to write the unit data and the parity in the nonvolatile memory at time of write in the first page, and to perform control to write the unit data in the nonvolatile memory at time of write in the second page; a decoder configured to perform an error correction process using the unit data and the parity read out from the nonvolatile memory; and a readout control unit configured to instruct the memory control unit to carry out readout using 2K−
1 first voltage values at time of readout from the first page and instruct the memory control unit to carry out readout using a second voltage values, which are different from the first voltage value and less in number than 2K−
1, at time of readout from the second page, and to select a bit value of the second page from a determination results of the bit value by the second voltage values based on the bit value of after the error correction of the first page;
wherein the memory control unit performs the readout from the nonvolatile memory based on an instruction from the readout control unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A storage device comprising:
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nonvolatile memory including a memory cell in which data of K bits is storable in one memory cell, where K is an integer greater than or equal to two, a first bit of the data of K bits representing data of a first page and a second bit representing data of a second page; and a memory controller configured to control the nonvolatile memory, wherein the memory controller includes, an encoder configured to encode unit data to write in the first page to generate a parity, a memory control unit configured to perform control to write the unit data and the parity in the nonvolatile memory at time of write in the first page, and to perform control to write the unit data in the nonvolatile memory at time of write in the second page; a decoder configured to perform an error correction process using the unit data and the parity read out from the nonvolatile memory, and a readout control unit configured to instruct the memory control unit to carry out readout using 2K−
1 first voltage values at time of readout from the first page and instruct the memory control unit to carry out readout using a second voltage values, which are different from the first voltage value and less in number than 2K−
1, at time of readout from the second page, and to select a bit value of the second page from a determination results of the bit value by the second voltage values based on the bit value of after the error correction of the first page; andthe memory control unit performs the readout from the nonvolatile memory based on an instruction from the readout control unit. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A memory control method for controlling nonvolatile memory including a memory cell in which data of K bits is storable in one memory cell, where K is an integer greater than or equal to two, a first bit of the data of K bits representing data of a first page and a second bit representing data of a second page, the memory control method comprising:
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encoding unit data to write in the first page, and generating a parity; controlling to write the unit data and the parity in the nonvolatile memory at time of write in the first page, and controlling to write the unit data in the nonvolatile memory at time of write in the second page; performing an error correction process using the unit data and the parity read out from the nonvolatile memory; carrying out readout using 2K−
1 first voltage values at time of readout from the first page; andcarrying out readout using a second voltage values, which are different from the first voltage values and less in number than 2K−
1, at time of readout from the second page, and selecting a bit value of the second page from a determination results of the bit value by the second voltage values based on the bit value of after the error correction of the first page.
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Specification