WO2010102566A1

WO2010102566A1 - Method for programming flash memory medium

Info

Publication number: WO2010102566A1
Application number: PCT/CN2010/070967
Authority: WO
Inventors: 钟智渊
Original assignee: 深圳市朗科科技股份有限公司
Priority date: 2009-03-11
Filing date: 2010-03-10
Publication date: 2010-09-16
Also published as: CN101833995A; CN101833995B

Abstract

A method for programming a flash memory medium is disclosed. It comprises: receiving a command for programming at least one page of the flash memory medium, selecting a target page to be currently programmed from at least one page, determining an associated page which is associated with the target page to be currently programmed based on the pre-determined associated relationships between every page of the flash memory medium, and judging whether the data in the associated page which has been determined can not be lost, wherein, if the data in the associated page can be lost, then the target page is programmed. The method will not result in the loss of the existing data in the flash memory medium even if an error occurs in programming a page, thereby protecting the existing data.

Description

Flash media shield programming method

Technical field

The present application relates to the field of semiconductor memory, and in particular to a method of programming a flash memory medium. Background technique

Currently, flash media is widely used in a variety of storage devices. However, due to the inherent defects of its flash memory, when a page is programmed (ie, a write operation), there is a possibility of a write failure. Since each page of the flash media is associated with a particular page, if a write to a page is in error, the page associated with that page may also be in error. If useful data is stored in the associated page, it will result in data loss. Summary of the invention

The present application is directed to the above disadvantages existing in the prior art.

The programming method of the flash medium according to the present application includes:

Receiving a command to program at least one page of the flash media;

Selecting, from the at least one page, a target page to be currently programmed; an associated page associated with the target page of the program;

It is judged whether the data in the determined associated page is not lost, wherein the target page is programmed if the data in the associated page can be lost.

Furthermore, if the result of the determining step is that the data in the associated page is not lost, then another page is selected from the at least one page as the target page to be currently programmed.

According to an embodiment of the invention, if a correspondence has been established between the associated page and its logical address in the flash medium, the data in the associated page may not be lost. According to another embodiment of the present invention, if the page number of the target page is larger than the page number of the associated page, the data in the associated page may not be lost. The step includes: determining whether the target page associated with the target page is the page pointed to by the received command, and if not, the data in the associated page cannot be lost. The above method can make the existing data not be protected even if the page programming error does not result in the loss of the existing data in the flash medium. DRAWINGS

1 is a flow chart of flash memory programming in accordance with an embodiment of the present disclosure; and FIG. 2 is a flow diagram of flash memory programming in accordance with another embodiment of the present disclosure. detailed description

The specific embodiments disclosed in the present application are described below with reference to the accompanying drawings. Embodiment 1

Referring to Fig. 1, the program processing 100 of the flash medium according to an embodiment disclosed in the present application starts from step S11. At step S11, a command to program the flash medium is received. As described in the background section, since each page of the flash medium has an association with another page, if a write operation to a page is in error, the page associated with the page may also be in error. If useful data is stored in the associated page, it will result in the loss of data.

In step S12, the first page pointed to by the received command is taken as the page to be currently programmed. In step S13, an associated page associated with the target page currently being programmed is determined based on a predetermined association relationship between pages in the flash media. Specifically, according to an embodiment, the relationship between pages in the flash medium may be recorded by one or more association tables, and an example of the contents of the association table is shown in Table 1:

Wherein, the association table may be stored in a flash memory medium. However, those skilled in the art should understand that the association table may also be stored in other locations, as long as it can be read when needed, for example, stored in ROM, PROM, OTPROM. , EEPROM, etc.

Taking Table 1 as an example, assuming that the page whose page number is "0" is determined to be the page currently to be written in step S12, the page number of the associated page is determined according to Table 1 in step S13. 4".

At step S14, it is determined whether the data in the associated page determined in step S13 is not lost. To judge. Specifically, if the page is associated with its logical address in the storage medium, the data of the page cannot be lost; otherwise, the data of the page can be lost.

Alternatively, the execution of the multi-page programming may be performed in the order of the page number (for example, programming the 0 page and then programming the 1 page), and therefore, in step S14, the associated target page may be associated with it. The page number size relationship of the associated page is used to determine whether the data in the associated page is not lost. Specifically, if the page number of the determined target page is greater than the page number of the associated page, the data in the associated page cannot be lost. For example, from the 0th page, continuous multi-page programming is started. When the target page is 3 pages, the data in the 0th page, 1st page, and 2nd pages of the related page before the 3rd page cannot be lost.

If the result of the judgment in step S14 is that the data in the associated page can be lost, the target page is programmed in step S15. Otherwise, another page is selected as the target page to be programmed in step S16.

Specifically, when step S15 is performed, the write command and the data to be written are first sent to the flash medium, and the data is written to the corresponding target page according to the write command. In one embodiment, the programming state of the flash media is also read after the data write operation (program states include "successful write" and "write error"). If the programming state is "successful write", subsequent programming is performed; if the programming state is "write error", subsequent programming is stopped, and the programming error is reported to the host through the communication line (such as the USB interface) of the host associated with the flash media. . The specific report programming error is based on the standard definition of the communication line protocol, such as the flash disk following the USB/SCSI protocol to report programming errors to the host.

In the following, the specific processing procedure of continuous multi-page programming for judging whether data in the associated page can be lost according to the logical address is described by taking Table 1 as an example. For the sake of brevity, the following description omits the step number Sl l -S16 „

Assuming that a command to program multiple pages in the flash medium is received, the page with the page number 0 indicated by the command is first used as the target page, and the associated page of the 0th page is found as the fourth page. It is judged that the fourth page does not have a correspondence with any logical address, that is, the data of the fourth page can be lost, and the page 0 is programmed. After that, the next page referred to by the command is the first page, and the related page of the first page is searched for the fifth page. After the data of the fifth page is judged to be lost, one page is programmed. Repeat the above process until the 4th page of the command is the target page. At this time, the related page of the 4th page is found as page 0. Since the data has been stored on page 0, the data on page 0 cannot be lost. In this case, another page in the flash medium, for example, page 5 is selected as the target page. Since the related page on page 5 is the first page, and the first page has also stored the data, another page in the flash medium is selected as the target page. The related page on page 6 is page 12, judged by the 12th The page data can be lost, so page 12 can be programmed. Here, the operation of selecting the next page in the flash media can select the next page of the page pointed by the command in the flash media, or select other empty pages. Embodiment 2

Referring to the method shown in FIG. 1 above, although multiple pages in the storage medium can be sequentially programmed according to the command, if the data in one page cannot be lost, the associated page is not programmed, so that the useful data is not guaranteed. Programming errors are lost, but can cause a lot of pages to be wasted.

In order to avoid wasting flash media, another method disclosed in accordance with the present application proposes a processing method 200 for programming a flash medium. According to this method, when all the pages indicated by a command complete the write operation, the command is successfully executed, and the result of the successful execution of the command is returned to the host. If any of the pages fails to write, the command fails to execute, and the host associated with the storage medium is processed for error (such as reporting an error to the host issuing the command, etc.), in which case the page has been successfully written. The data is also considered to be lossable, and the associated pages of these pages can be written. The specific operation thereof will be described below with reference to Fig. 2 .

At step S21, a command to request writing of at least one page in the flash medium is received from the host. At step S22, the first page indicated by the command is used as the target page for which data is to be written. In step S23, the associated page of the target page is found according to the association relationship between the pre-established pages. In step S24, it is judged whether the associated page and the target page are the pages pointed to by the same command, and if so, the data is written to the target page in step S27, otherwise step S25 is performed.

In step S25, it is judged whether the data in the associated page is not lost, and if the data can be lost, the data is written in the target page, otherwise step S26 is performed.

In step S26, another page in the flash medium is selected as the target page, and the process returns to step S23, and step S23-26 is sequentially executed.

When the target page is programmed in step S27, it is determined in step S28 whether the programming is in error, if the error occurs, step S210 is performed, otherwise step S29 is performed;

In step S29, it is determined whether the page pointed to by the command has been completely executed. If the execution has been completed, the flow of programming for a plurality of consecutive pages is ended, and the execution of the command is reported to the host; if it has not been completed, the process returns to step S22.

In step S210, error processing is performed. For example, aborting a program command and reporting an error to the host. Specifically, the above steps are further explained by taking a case of programming ten consecutive pages as an example. In step S22, step 13 and subsequent steps shown in Fig. 2 are executed from the first page indicated by the command as the target page. When it is determined to step S29, it is determined that the command has not been executed yet, then return to the next page (ie, page 2) indicated by the sequential acquisition command in step 22 as the target page, and then perform step 23 and subsequent steps, .. ..... By analogy, until the 10th page indicated by the command is also programmed, it is determined in step S29 that all the pages indicated by the command have been programmed, and the command execution is completed.

In order to facilitate the implementation of the above process, the embodiment may use the associated page table RelatedPage to record the relationship between the pages. Following the above Table 1, the data structure of the associated page table RelatedPage is as follows:

Const BYTE RelatedPage[128] =

4, 〃 Page 0

5,// Page 1

8,// Page 2

9,11 Page 3

0,// Page 4

1 J I Page 5

12, // Page 6

13, // Page 7

2JI Page 8

3, 〃 Page 9

}.

In this embodiment, the variable FirstFreePage records the first empty page in the storage medium that can be programmed, and sets the variable FirstRiskPage to record which page in the storage medium is not lost in the page, that is, the page number of the page before the FirstRiskPage is It cannot be lost. According to one embodiment, the variables FirstFreePage and FirstRiskPage, such as, but not limited to, are set in the controller memory for programming the flash media, all of which are integers and initialized to a value of zero.

If a command is required to program the storage medium, when the above step S22 is performed, the value of reading FirstFreePage is 0, that is, the 0th page is used as the target page; in step S23, the associated page table is found, and the 0th page is found. The associated page is page 4; in step S24, it is determined whether the 4th page and the 0th page are pages pointed to by the same command according to the programming length specified by the command and the length of each page of the flash medium. Specifically, the command specifies that the programming length is 100 sectors, and the length of each page of the flash media is 2k or 4 sectors. And the current target page is page 0, the command specifies the programming length divided by the length of each page of the flash media, and the number of pages required to execute the command is 25, that is, the pages from 0 to 25 are the pages pointed to by the same command, so , judged that page 4 and page 0 are the same command. Correspondingly, pages 25 and 26 are not the pages pointed to by the same command.

In step S25, the page number of the page of the associated page is compared with the value of the FirstRiskPage, and the page number of the associated page is greater than the value of the firstRiskPage. Therefore, it is determined that the data of the fourth page can be lost, and step S27 is performed. Page programming.

When it is determined in step S29 that it is determined that the command has not been executed, the process returns to step S22, and the value of FirstFreePage is incremented by one, and the value of FirstRiskPage is set to the same value as FirstFreePage, that is, 1, and the above process is re-executed. Receive the next command.

When another command is required to program the four pages of the current block, according to the above procedure, when the step S22 is performed, the value of the first FreePage is 1; in step S23, the page associated with the first page is the 5th page. The page number 5 of the associated page is larger than the value of FirstRiskPage, so the first page can be programmed. Because the data of these four pages is a continuous and complete data, any page of data can be lost during the programming process, so it is not necessary to increment the value of FirstRiskPage during continuous multi-page programming. A total addition can be done after the continuous programming process. That is, every time you finish programming a page, FirstFreePage takes 1 and FirstRiskPage does not change until all four pages are programmed. At this time, FirstFreePage may be equal to 6, and FirstRiskPage is also set to the same value as FirstFreePage, and then received. One order.

According to an embodiment of the present invention, in the above flow, after the page is programmed in step S27, the program state of the page is read to confirm whether the page is programmed incorrectly. If programming errors occur, report to the host that the command execution failed, asking the host to resend the data, or write the data in the cache to other blocks or other pages.

According to the characteristics of the flash media, the range of association between the general pages is limited to six pages, that is, the page number difference between the page and its associated page does not exceed 6, so the present embodiment can find the associated page only in the first six pages of the target page. To improve the efficiency of the search. Of course, those skilled in the art should understand that the above embodiment is also applicable to the case where the range of association between pages is not limited to six pages. The above embodiment can find the associated page only within the association range of the target page. In addition, the above embodiments may also not use variables.

FirstRiskPage records the page whose data cannot be lost, but records the information of the page whose data cannot be lost in the reserved area of the flash medium. Finding the record can determine whether the associated page data can be lost. The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention, and is equivalent to the equivalent structure or equivalent process transformation of the present specification and the drawings, or directly or indirectly The technical field is equally included in the scope of patent protection of the present invention.

Claims

Claims:

1. A method of programming a flash medium, comprising:

Receiving a command to program at least one page of the flash media;

Selecting a target page to be programmed from the at least one page;

Determining an associated page associated with the target page currently being programmed based on a predetermined association relationship between pages in the flash media;

2. The method of claim 1 further comprising:

If the result of the determining step is that the data in the associated page is not lost, then another page is selected from the at least one page as the target page to be currently programmed.

3. The method of claim 1, the step of determining whether the determined data in the associated page is not lossable further comprises: whether the data in the page is not lost, if the associated page is in the flash medium A correspondence has been established between the logical addresses, and the data in the associated page cannot be lost.

4. The method of claim 1, the step of determining whether the determined data in the associated page is not lost further comprises:

Determining, according to the page number size relationship of the selected target page and its associated associated page, whether the data in the associated page is not lost, if the page number of the target page is greater than the page number of the associated page, The data in the associated page cannot be lost.

5. The method of claim 1, the step of determining whether the determined data in the associated page is not lossable further comprises: a face, if not, the data in the associated page is not lost.

6. The method of claim 1 further comprising:

If an error occurs during programming of the target page, an error report is sent to the host associated with the storage medium.

S

7. The method of claim 1, wherein the predetermined association relationship is recorded in an association table

The method of claim 7, wherein the association table is stored in the storage medium. The method of any one of claims 8 to 8, wherein programming the target page comprises writing data to the target page.