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NandFlash bad block management method

A bad block and block number technology, applied in the field of NandFlash bad block management, can solve the problems of increased memory capacity and large memory, and achieve the effects of strong adaptability, high production efficiency and strong versatility

Active Publication Date: 2013-02-13
FEITIAN TECHNOLOGIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The inventor finds in the process of realizing the present invention that there are at least the following defects in the prior art: the method of directly establishing the mapping table takes up a lot of memory, and the memory capacity taken will also increase exponentially with the increase of the NandFlash capacity

Method used

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  • NandFlash bad block management method
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  • NandFlash bad block management method

Examples

Experimental program
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Embodiment 1

[0049] see figure 1 , the embodiment of the present invention provides a kind of NandFlash bad block management method, and described method specifically comprises:

[0050] Step S1: Check whether the initial bad block scanning flag is set, if yes, directly execute step S3, otherwise execute step S2;

[0051] Step S2: Perform an initial bad block scan, find a replacement block for the scanned bad block, generate a corresponding record and write it into the bad block replacement area, and set the initial bad block scan flag after the initial bad block scan is completed;

[0052] Step S3: Create a bitmap, set the values ​​of all data bits in the bitmap to the first preset value, read the records in the bad block replacement area, and compare the information in the bitmap according to the records. The value of the data bit corresponding to each bad block is set as the second preset value to carry out bitmap marking, and waits to receive a block operation request after the bitmap m...

Embodiment 2

[0064] The embodiment of the present invention provides a kind of NandFlash bad block management method, described method specifically comprises four parts of initial bad block scanning, bitmap creation and mark, block operation and bitmap update, present embodiment respectively initial bad block scanning and Bitmap creation and marking as a process, block manipulation and bitmap update as a process are described.

[0065] see figure 2 , the process of initializing bad block scanning and bitmap creation and marking includes the following steps:

[0066] Step 101: Check whether the initial bad block scanning flag is set, if yes, execute step 114, otherwise execute step 102;

[0067] Wherein, the initial bad block scanning flag is used to identify whether the initial bad block scanning is completed, and the initial scanning flag is in a reset state when the NandFlash leaves the factory, and is set when the initial bad block scanning is completed.

[0068] Step 102: locate the...

Embodiment 3

[0117] The embodiment of the present invention provides a kind of NandFlash bad block management method, described method specifically comprises four parts of initial bad block scanning, bitmap creation and mark, block operation and bitmap update, present embodiment respectively initial bad block scanning and Bitmap creation and marking as a process, block manipulation and bitmap update as a process are described.

[0118] The process of initial bad block scanning and bitmap creation and marking is the same as the method in Embodiment 2, and will not be repeated here;

[0119] see Figure 4 , the block operation and bitmap update process includes the following steps:

[0120] Step 301: When receiving a block operation request, check whether the NandFlash unavailable flag is set, if so, it will prompt that NandFlash is unavailable, and the operation fails, otherwise step 302 is performed;

[0121] Step 302: Judging whether the block number involved in the block operation requ...

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Abstract

The invention discloses a NandFlash bad block management method and belongs to the field of memories. The method comprises the following steps of: performing initial bad block scanning, looking for a substitutive block for the scanned bad block, generating corresponding record and writing the record in a bad block substitution region, creating a bitmap list after the initial bad block scanning, performing bitmap marking on the record in the bad block substitution region, judging whether the block related in the operation request is bad block according to the mark in the bitmap when receiving a block operation request, if so, looking for the substitutive block of the bad block and operating the substitutive block, if not, operating the current block, adding or amending the record in the bad block record if the bad block appears during the operation process, and adding the mark of the new bad block in the bitmap list. The NandFlash bad block management method has the beneficial effects of supporting high capacity NandFlash chips under the condition of occupying small internal memory and improving the access speed of the NandFlash chips.

Description

technical field [0001] The invention belongs to the field of memory, in particular to a NandFlash bad block management method. Background technique [0002] NandFlash is a kind of Flash memory, which uses a non-linear macro-cell mode inside, which provides a cheap and effective solution for the realization of solid-state large-capacity memory. NandFlash memory has the advantages of large capacity and fast rewriting speed, and is suitable for the storage of large amounts of data, so it has been more and more widely used in the industry, such as embedded products including digital cameras, MP3 walkman memory cards, small and exquisite U disk, etc. [0003] NandFlash has the possibility of bad blocks when it is used for the first time, and bad blocks will also be generated during use. Currently, the method of establishing a mapping table is used to manage bad blocks of NandFlash. [0004] The inventor found in the process of realizing the present invention that at least the f...

Claims

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Application Information

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IPC IPC(8): G06F12/06
Inventor 陆舟于华章
Owner FEITIAN TECHNOLOGIES
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