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US 9,286,204 B2Granted
Memory controller
AssigneeMitsubishi Electric Corporation
InventorsKoji Kikkawa, Masanori Nakata
Life of this patent
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Abstract
A microcomputer retains a group definition table associating the sector sections created by dividing all sectors into multiple sections under a given condition with different memory regions on a flash memory, respectively. A memory control section makes reference to the group definition table to identify a memory region corresponding to a specified sector, and searches the identified memory region range for a physical address corresponding to the specified sector. Furthermore, the memory control section moves a specified sector within the identified memory region range for rewriting data corresponding to the specified sector.
Claims5
A memory controller, comprising:
- a memory control section-that accesses a readable/writable nonvolatile memory and reads and writes data on the basis of a sector unit of a file system established for the nonvolatile memory;
- and
- a table storage that stores a table that associates sector sections created by dividing all sectors of the file system into multiple sections under a given condition with different memory regions on the nonvolatile memory, respectively, and with an accumulated number of times obtained by accumulating a number of times of moving the sectors as a result of the execution of a garbage collection, the different memory regions each comprising a plurality of purging blocks,
- wherein the memory control section:
- makes reference to the table to identify a memory region corresponding to a specified sector, and searches the identified memory region range for a physical address corresponding to the specified sector;
- moves a specified sector within the identified memory region range for rewriting data corresponding to the specified sector;
- writes data;
- and
- by executing the garbage collection in which whether a number of free sectors belonging to the identified memory region is equal to or greater than a given number is determined, a purging block is selected as a purging target if the number of free sectors is less than the given number, and all used sectors within the selected purging-target purging block are moved to another purging block in the identified memory region, and
- purging the purging-target purging block after the execution of the garbage collection,
- changes a correspondence between the sector sections and the memory regions in the table based on the accumulated number of times.
8 more elements
A memory access method comprising
- a memory control step that accesses a readable/writable nonvolatile memory and reads and writes data on the basis of a sector unit of a file system established for the nonvolatile memory,
- wherein in the memory control step:
- a table is referred to identify a memory region corresponding to a specified sector, and to search the identified memory region range for a physical address corresponding to the specified sector, wherein the table associates sector sections created by dividing all sectors of the file system into multiple sections under a given condition with different memory regions on the nonvolatile memory, respectively, and with an accumulated number of times obtained by accumulating a number of times of moving the sectors as a result of the execution of a garbage collection, the different memory regions each comprising a plurality of purging blocks;
- a specified sector is moved within the identified memory region range for rewriting data corresponding to the specified sector;
- for writing data, the garbage collection in which whether a number of free sectors belonging to the identified memory region is equal to or greater than a given number is determined, a purging block is selected as a purging target if the number of free sectors is less than the given number, and all used sectors within the selected purging-target purging block are moved to another purging block in the identified memory region, is executed and the purging-target purging block is purged after the execution of the garbage collection;
- and
- a correspondence between the sector sections and the memory regions in the table is changed based on the accumulated number of times.
4 more elements
Dependencies are inferred from the claim text.