Data writing method, memory controller and memory storage apparatus

• US 8,560,926 B2
• Filed: 05/23/2011
• Issued: 10/15/2013
• Est. Priority Date: 04/21/2011
• Status: Active Grant

• Current Assignee: Phison Electronics Corporation
• Original Assignee: Phison Electronics Corporation
• Inventors: Yeh, Chih-Kang
• Primary Examiner(s): Chung, Phung M
• Application Number:
  US13/114,037
• Publication Number:
  US 20120272123A1
• Time in Patent Office: 876 Days
• Field of Search: 714/773, 714/746, 714/738, 714/736, 714/718, 711/173, 711/171, 365/185.33, 365/230.03
• US Class Current: 714/773
• CPC Class Codes: G06F 11/1044 with specific ECC/EDC distribution
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/401 Compressed data
• CPC Class Codes: G06F 2212/403 Error protection encoding, e.g. using parity or ECC codes
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7207 management of metadata or control data

Abstract

A data writing method for writing page data into a rewritable non-volatile memory module is provided, the rewritable non-volatile memory module has a plurality of physical blocks, and each of the physical blocks has a plurality of physical pages. The data writing method includes grouping the physical pages into a plurality of physical page groups according to write speed of each physical page. The data writing method also includes compressing the page data to generate compressed data and calculating a data compression ratio corresponding to the compressed data. The data writing method further includes writing the compressed data into one of the physical pages in a corresponding physical page group among the physical page groups according to the data compression ratio. Accordingly, the data writing method can effectively ensure the accuracy of data stored in the rewritable non-volatile memory module.

Claims

1. A data writing method for writing page data into a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of physical blocks, and each of the physical blocks has a plurality of physical pages, the data writing method comprising:

grouping the physical pages into a plurality of physical page groups according to write speed of each of the physical pages by a memory controller, wherein the physical page groups includes a first physical page group and a second physical page group and write speed of writing data into the physical pages belonging to the first physical page group are faster than write speed of writing data into the physical pages belonging to the second physical page group;

compressing the page data to generate compressed data by the memory controller;

calculating a data compression ratio corresponding to the compressed data by the memory controller; and

writing the compressed data into one of the physical pages in a corresponding physical page group among the physical page groups according to the data compression ratio by the memory controller,

wherein the step of writing the compressed data into one of the physical pages in the corresponding physical page group among the physical page groups according to the data compression ratio comprises;

generating an error checking and correcting (ECC) code corresponding to the compressed data by the memory controller;

generating an ECC frame according to the compressed data and the ECC code by the memory controller;

determining whether the data compression ratio corresponding to the compressed data is greater than a predetermined threshold by the memory controller;

when the data compression ratio corresponding to the compressed data is greater than the predetermined threshold, writing the ECC frame into one of the physical pages belonging to the second physical page group by the memory controller; and

when the data compression ratio corresponding to the compressed data is not greater than the predetermined threshold, writing the ECC frame into one of the physical pages belonging to the first physical page group by the memory controller.

2. The data writing method according to claim 1, wherein the step of generating the ECC frame according to the compressed data and the ECC code comprises:

combining the compressed data, the ECC code, and at least one padding bit data to generate the ECC frame by the memory controller,

wherein the size of the ECC frame is equal to one physical page capacity.

3. The data writing method according to claim 1, wherein the step of generating the ECC frame according to the compressed data and the ECC code comprises:

obtaining sub page data from the page data by the memory controller; and

combining the compressed data, the ECC code, and the sub page data to generate the ECC frame by the memory controller,

wherein the size of the ECC frame is equal to one physical page capacity.

4. The data writing method according to claim 1, wherein the rewritable non-volatile memory module further comprises a control circuit, and the control circuit inserts dummy data behind the compressed data and the ECC code.

5. The data writing method according to claim 1 further comprising:

receiving a plurality of additional page data by the memory controller;

respectively compressing the additional page data to generate a plurality of additional compressed data by the memory controller;

calculating a data compression ratio corresponding to each of the additional compressed data by the memory controller;

re-sorting the additional compressed data according to the data compression ratios corresponding to the additional compressed data by the memory controller; and

writing the re-sorted additional compressed data into the physical pages by the memory controller.

6. A data writing method for writing page data into a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of physical blocks, each of the physical blocks has a plurality of physical pages, and the physical pages are categorized into a plurality of fast physical pages and a plurality of slow physical pages, the data writing method comprising:

grouping the physical blocks into a first physical block group and a second physical block group by a memory controller;

compressing the page data to generate compressed data by the memory controller;

calculating a data compression ratio corresponding to the compressed data by the memory controller;

determining whether the data compression ratio corresponding to the compressed data is greater than a predetermined threshold by the memory controller;

when the data compression ratio corresponding to the compressed data is greater than the predetermined threshold, writing the compressed data into a fast physical page or a slow physical page among the physical pages in the physical blocks belonging to the second physical block group by the memory controller; and

when the data compression ratio corresponding to the compressed data is not greater than the predetermined threshold, writing the compressed data into a fast physical page among the physical pages in the physical blocks belonging to the first physical block group by the memory controller.

7. A memory controller for writing page data from a host system into a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of physical blocks, and each of the physical blocks has a plurality of physical pages, the memory controller comprising:

a host interface, configured to couple to the host system;

a memory interface, configured to couple to the rewritable non-volatile memory module;

a data compression/decompression circuit, coupled to the host interface and configured to compress the page data to generate compressed data and calculate a data compression ratio corresponding to the compressed data;

a memory management circuit, coupled to the data compression/decompression circuit; and

an ECC circuit coupled to the memory management circuit and configured to generate an ECC code corresponding to the compressed data;

wherein the memory management circuit is configured to group the physical pages into a plurality of physical page groups according to write speed of each of the physical pages, wherein the physical page groups includes a first physical page group and a second physical page group and write speed of writing data into the physical pages belonging to the first physical page group are faster than write speed of writing data into the physical pages belonging to the second physical page group,

wherein the memory management circuit generates an ECC frame according to the compressed data and the ECC code and determines whether the data compression ratio corresponding to the compressed data is greater than a predetermined threshold,

when the data compression ratio corresponding to the compressed data is greater than the predetermined threshold, the memory management circuit writes the ECC frame into one of the physical pages belonging to the second physical page group, and

when the data compression ratio corresponding to the compressed data is not greater than the predetermined threshold, the memory management circuit writes the ECC frame into one of the physical pages belonging to the first physical page group.

8. The memory controller according to claim 7,

wherein the memory management circuit combines the compressed data, the ECC code, and at least one padding bit data to generate the ECC frame,

wherein the size of the ECC frame is equal to one physical page capacity.

9. The memory controller according to claim 7,

wherein the memory management circuit obtains sub page data from the page data and combines the compressed data, the ECC code, and the sub page data to generate the ECC frame,

wherein the size of the ECC frame is equal to one physical page capacity.

10. The memory controller according to claim 7, wherein the rewritable non-volatile memory module further comprises a control circuit, and the control circuit inserts dummy data behind the compressed data and the ECC code.

11. The memory controller according to claim 7, wherein the memory management circuit receives a plurality of additional page data, respectively compresses the additional page data to generate a plurality of additional compressed data, calculates a data compression ratio corresponding to each of the additional compressed data, re-sorts the additional compressed data according to the data compression ratios corresponding to the additional compressed data, and writes the re-sorted additional compressed data into the physical pages.

12. A memory storage apparatus, comprising:

a connector, configured to couple to a host system;

a rewritable non-volatile memory module, having a plurality of physical blocks, wherein each of the physical blocks has a plurality of physical pages; and

a memory controller, coupled to the connector and the rewritable non-volatile memory module,

wherein the memory controller is configured to receive page data from the host system,

wherein the memory controller is further configured to compress the page data to generate compressed data and calculate a data compression ratio corresponding to the compressed data,

wherein the memory controller is further to group the physical pages into a plurality of physical page groups according to write speed of each of the physical pages, wherein the physical page groups includes a first physical page group and a second physical page group and write speed of writing data into the physical pages belonging to the first physical page group are faster than write speed of writing data into the physical pages belonging to the second physical page group,

wherein the memory controller generates an ECC code corresponding to the compressed data,

wherein the memory controller generates an ECC frame according to the compressed data and the ECC code and determines whether the data compression ratio corresponding to the compressed data is greater than a predetermined threshold,

when the data compression ratio corresponding to the compressed data is greater than the predetermined threshold, the memory controller writes the ECC frame into one of the physical pages belonging to the second physical page group, and

when the data compression ratio corresponding to the compressed data is not greater than the predetermined threshold, the memory controller writes the ECC frame into one of the physical pages belonging to the first physical page group.

13. The memory storage apparatus according to claim 12,

wherein the memory controller combines the compressed data, the ECC code, and at least one padding bit data to generate the ECC frame,

wherein the size of the ECC frame is equal to one physical page capacity.

14. The memory storage apparatus according to claim 12,

wherein the memory controller obtains sub page data from the page data and combines the compressed data, the ECC code, and the sub page data to generate the ECC frame,

wherein the size of the ECC frame is equal to one physical page capacity.

15. The memory storage apparatus according to claim 12, wherein the rewritable non-volatile memory module further comprises a control circuit, and the control circuit inserts a dummy data behind the compressed data and the ECC code.

16. The memory storage apparatus according to claim 12, wherein the memory controller receives a plurality of additional page data, respectively compresses the additional page data to generate a plurality additional compressed data, calculates a data compression ratio corresponding to each of the additional compressed data, re-sorts the additional compressed data according to the data compression ratios corresponding to the additional compressed data, and writes the re-sorted additional compressed data into the physical pages.