METHOD FOR MANAGING THRESHOLD VOLTAGE, AND METHOD FOR READING FLASH DATA

Abstract

The present application provides a method for managing a threshold voltage, a method for reading flash data, a solid state disk controller, and a solid state disk. The method for managing a threshold voltage includes: acquiring a target block with a specific region, the specific region having a determined first piece of cell state distribution information: and when a preset scanning interval is reached, scanning the threshold voltage based on the specific region of the target block, the first piece of cell state distribution information, and an optimal threshold voltage table, and periodically managing the optimal threshold voltage table.

Description

Claims

1. A method for managing a threshold voltage, comprising: acquiring a target block with a specific region, the specific region having a determined first piece of cell state distribution information; andwhen a preset scanning interval is reached, scanning the threshold voltage based on the specific region of the target block, the first piece of cell state distribution information, and an optimal threshold voltage table, and periodically managing the optimal threshold voltage table.

2. The method according to claim 1, wherein the specific region comprises a word line in the target block, the word line comprising a preset data sequence for generating the first piece of cell state distribution information.

3. The method according to claim 2, wherein scanning the threshold voltage based on the specific region of the target block, the first piece of cell state distribution information, and the optimal threshold voltage table comprises: performing a read operation on the specific region respectively according to each threshold voltage recorded in the optimal threshold voltage table, and acquiring a second piece of cell state distribution information corresponding to the each threshold voltage;acquiring an offset parameter of the each threshold voltage according to the first piece of cell state distribution information and the second piece of cell state distribution information; andupdating each threshold voltage recorded in the optimal threshold voltage table according to the offset parameter.

4. The method according to claim 3, wherein acquiring the offset parameter of the each threshold voltage according to the first piece of cell state distribution information and the second piece of cell state distribution information comprises: acquiring an initial number of cells and an initial record value according to the first piece of cell state distribution information;acquiring a current number of cells and a current record value corresponding to the each threshold voltage according to the second piece of cell state distribution information; andcomparing the initial number of cells with the current number of cells to obtain an offset direction of the each threshold voltage, and comparing the initial record value with the current record value to obtain an offset degree of the each threshold voltage.

5. The method according to claim 4, wherein updating each threshold voltage recorded in the optimal threshold voltage table according to the offset parameter comprises: determining an adjusted threshold voltage according to the offset direction and the offset degree of the threshold voltage, and updating and recording the adjusted threshold voltage in the optimal threshold voltage table.

6. The method according to claim 1, further comprising: acquiring an updated threshold voltage in the optimal threshold voltage table and an initial threshold voltage corresponding to the updated threshold voltage;computing an offset amount between the updated threshold voltage and the initial threshold voltage; andperforming a data transfer operation when the offset amount is greater than a set threshold.

7. The method according to claim 6, wherein acquiring the updated threshold voltage in the optimal threshold voltage table comprises periodically scanning the optimal threshold voltage to establish the optimal threshold voltage table.

8. The method according to claim 7, wherein periodically scanning the optimal threshold voltage comprises: selecting a target block; andascertaining whether scanning time reaches a preset scanning interval.

9. The method according to claim 8, wherein when the scanning time reaches the preset scanning interval, the method further comprises: determining a corresponding word line, and scanning a threshold voltage; andascertaining whether a difference between the threshold voltage obtained by the scanning and an initial threshold voltage is greater than a set threshold.

10. The method according to claim 8, wherein when the scanning time does not reach the preset scanning interval, the method further comprises: completing the scanning.

11. The method according to claim 9, wherein when the difference between the threshold voltage obtained by the scanning and the initial threshold voltage is greater than the set threshold, the method further comprises: transferring data in a block corresponding to the word line; andascertaining whether scanning of all written blocks is completed.

12. The method according to claim 9, wherein when the difference between the threshold voltage obtained by the scanning and the initial threshold voltage is less than or equal to the set threshold, the method further comprises: recording the threshold voltage in the optimal threshold voltage table; andascertaining whether scanning of all written blocks is completed.

13. The method according to claim 12, wherein: when the scanning of all written blocks is not completed, the method further comprises: repeating the selecting of a target block and the ascertaining of whether scanning time reaches a preset scanning interval whether; andwhen the scanning of all written blocks is completed, the method further comprises: completing the scanning.

14. A method for reading flash data, comprising: reading data in a NAND flash according to a received read command;acquiring an optimal threshold voltage according to an optimal threshold voltage table when there is an uncorrectable error during reading the flash data, wherein the optimal threshold voltage table is determined according to the method for managing the threshold voltage according to claim 1; andre-performing a read operation according to the optimal threshold voltage to read the flash data.

15. The method according to claim 14, wherein when the re-performing the read operation according to the optimal threshold voltage fails, the method further comprises: performing an optimal threshold voltage scanning to obtain the optimal threshold voltage;performing a read operation for a target region according to the obtained optimal threshold voltage; andperforming a data transfer operation on the data corresponding to the read command when the read operation succeeds.

16. A solid state disk controller, comprising: one or more processors and a memory storing a program, wherein when the program is executed by the one or more processors, the program causes the solid state disk controller to execute operations for managing a threshold voltage, wherein the operations comprise: acquiring a target block with a specific region, the specific region having a determined first piece of cell state distribution information; andwhen a preset scanning interval is reached, scanning the threshold voltage based on the specific region of the target block, the first piece of cell state distribution information, and an optimal threshold voltage table, and periodically managing the optimal threshold voltage table.

17. The solid state disk controller according to claim 16, wherein the specific region comprises a word line in the target block, the word line comprising a preset data sequence for generating the first piece of cell state distribution information.

18. The solid state disk controller according to claim 17, wherein scanning the threshold voltage based on the specific region of the target block, the first piece of cell state distribution information, and the optimal threshold voltage table comprises: performing a read operation on the specific region respectively according to each threshold voltage recorded in the optimal threshold voltage table, and acquiring a second piece of cell state distribution information corresponding to the each threshold voltage;acquiring an offset parameter of the each threshold voltage according to the first piece of cell state distribution information and the second piece of cell state distribution information; andupdating each threshold voltage recorded in the optimal threshold voltage table according to the offset parameter.

19. The solid state disk controller according to claim 18, wherein acquiring the offset parameter of the each threshold voltage according to the first piece of cell state distribution information and the second piece of cell state distribution information comprises: acquiring an initial number of cells and an initial record value according to the first piece of cell state distribution information;acquiring a current number of cells and a current record value corresponding to the each threshold voltage according to the second piece of cell state distribution information; andcomparing the initial number of cells with the current number of cells to obtain an offset direction of the each threshold voltage, and comparing the initial record value with the current record value to obtain an offset degree of the each threshold voltage.