CN111290716A - Abrasion balance processing method based on Norflash - Google Patents

Abstract

The invention relates to a wear-leveling processing method based on Norflash, which comprises the steps of taking a certain section of area at the front part or the rear part of a sector to record the erasing times of the sector; when a new sector needs to be used, the current sector erasing frequency condition of the system is scanned, the deviation value of the system erasing is compared with a set threshold value, and an idle sector is selected. The erasing times of the sector are recorded by taking a certain section of area at the front part or the rear part of the sector. Thus, the number of erasures per sector is accurately recorded. And records the information in the memory every time the system is started. This allows the erasure information of all sectors to be retrieved quickly.

Description

A wear leveling treatment method based on Norflash

technical field

The invention relates to the field of embedded data storage, in particular to a Norflash-based wear leveling processing method.

Background technique

Based on cost considerations, many embedded systems currently use a single-chip Norflash storage medium to store programs and data. Generally, the Norflash space used is very small, ranging from tens of K to several M.

Norflash contains multiple sectors, and each sector can be programmed individually and multiple times, as long as the data written each time can write 1 to 0. For example, 0xff can be written as 0xfe, and 0xfe can be written as 0xfc, but if 0 needs to be written as 1, for example, 0xfe needs to be written as 0xff, the entire sector needs to be erased and then rewritten.

The life of each sector of Norflash is calculated separately, generally speaking, there are 10W erasing times.

In order to prevent some sectors from terminating their life too quickly and prematurely, a wear leveling algorithm is usually used to ensure that the lifespan of all sectors is balanced.

In order to achieve wear leveling, it is common practice to delineate a part of the functional area in the flash to record the erasure times of each sector, such as Figure 1, where 1, 2, 3... are sector numbers in Figure 1.

When the system needs to use the free sector to write recorded data, it needs to query the recorded sector life information, and select a suitable sector from it.

This approach has obvious disadvantages:

(1) These functional areas themselves also have a lifespan problem. In order to support these large-scale erasing and recording requirements, a large number of functional areas are required, which results in a relatively large waste of space.

(2) In different usage scenarios, the lifespan between functional areas is actually not balanced. For example, the lifespan of the area used for recording lifespan may be shorter than that of the data area.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a Norflash-based wear leveling processing method, which can allocate the life of each sector based on the wear leveling condition, and realize the wear leveling among the sectors to the greatest extent.

The present invention adopts the following scheme to realize: a kind of wear leveling treatment method based on Norflash,

Before each sector of Norflash is used, record the erasing times of each sector in the front or rear of the corresponding sector; when a new sector needs to be used, scan the erasing times of all current sectors In this case, compare the deviation value of sector erasing with the set threshold, and select a free sector.

Further, let the erasing times corresponding to each sector of the embedded system be C ₁ , C ₂ . . . Cn respectively, where n is the number of the sector; Cmax represents the maximum erasing times in the system, and Cmin represents the system The minimum number of erasing in the system, let the deviation value of the number of erasures of the sector be D, D=Cmax-Cmin; set a maximum deviation value of the number of erasing of the system Dmax, the range of Dmax is 1% of the erasing life of the sector to 1% 1 thousand points; that is, only the maximum erasure times deviation value Cmax-Cmin<=Dmax in the system is allowed;

When the system needs a new sector, the D value of the current system is judged. When D < the set threshold Dmax, a sector is randomly allocated from the system; when D>= the set threshold Dmax, Cmin is allocated The corresponding sector is used by the system; if the content of the found sector is empty, it is used by the system; if there is valid data in this sector, the valid data will be transferred to other sectors before being used by the system.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention takes the front part or the rear part of the sector to take a certain area to record the erasing times of the sector. In this way, the number of erasures of each sector is accurately recorded. And each time the system starts, the information is recorded in the memory. Doing so quickly retrieves erasure information for all sectors.

(2) When D<Dmax, the present invention can randomly acquire an available sector, reduce the number of sectors with the minimum number of erasures located each time, and greatly improve the efficiency of querying the operation of the embedded system, that is, the system does not need to spend a lot of time to find a suitable available sector.

Description of drawings

FIG. 1 is a schematic diagram of sector division recording and erasing times in the prior art according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of recording and erasing times at the rear of the sector during sector division according to an embodiment of the present invention.

3 is a schematic diagram of recording and erasing times at the front of a sector during sector division according to an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

This embodiment provides a Norflash-based wear leveling processing method. Before each sector of Norflash is used, the erasing times of each sector are respectively recorded in the front or rear of the corresponding sector; When a new sector is created, scan the current erasing times of all sectors, compare the deviation value of sector erasing with the set threshold, and select a free sector.

In this embodiment, the erasing times corresponding to each sector of the embedded system are respectively C ₁ , C ₂ . . . Cn, where n is the number of the sector; assuming that Cmax represents the erasure in the embedded system The maximum number of times, Cmin represents the minimum number of erasing times in the embedded system. Assuming that the sector erasure deviation value of the embedded system is D, then D=Cmax-Cmin; set a maximum deviation value of the system erasing times as needed Dmax, that is, only the maximum erasure times Cmax-Cmin<=Dmax is allowed in the system; Dmax is typically taken as 1/100 – 1/1000 of the erasure life of the sector to achieve the best performance and life overhead. For example, if the erasing life of a sector is 100,000 times, the value of Dmax can be between 100 and 1000.

When the system needs a new sector, the D value of the current system is judged. When D < the set threshold Dmax, a sector is randomly allocated from the system; when D>= the set threshold Dmax, Cmin is allocated The corresponding sector is used by the system; if the content of the found sector is empty, it is used by the system; if there is valid data in this sector, the valid data will be transferred to other sectors before being used by the system.

The method of this embodiment is to use the feature of Norflash that can be programmed multiple times to record the number of erasures in the front or rear part of the sector itself, and the erasure information of these sectors follows their own sectors. The purpose is to avoid Cmax-Cmin > Dmax. The advantage of this processing is that in the case of wear leveling, the life of each sector is allocated, and the wear leveling between sectors is achieved to the greatest extent.

As shown in Figure 2 and Figure 3, C1 represents the erasing times of the sector. Take the front or rear of the sector and take a certain area to record the erasing times of the sector. In this way, the number of erasures of each sector is accurately recorded.

And each time the system starts, the information is recorded in the memory. Doing so quickly retrieves erasure information for all sectors.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (2)

1. a kind of wear leveling treatment method based on Norflash, is characterized in that: Before each sector of Norflash is used, record the erasing times of each sector in the front or rear of the corresponding sector; when a new sector needs to be used, scan the erasing times of all current sectors In this case, compare the deviation value of sector erasing with the set threshold, and select a free sector. 2. a kind of wear leveling treatment method based on Norflash according to claim 1, is characterized in that: Let the erasing times corresponding to each sector of the embedded system be C ₁ , C ₂ ... Cn, where n is the number of the sector; Cmax represents the maximum erasing times in the system, and Cmin represents the smallest erasing times in the system. Erasing times, let the deviation value of sector erasing times be D, D=Cmax-Cmin; set a maximum deviation value of system erasing times Dmax, the range of Dmax is 1 percent to 1 thousandth of the erasing life of the sector ; That is, only the maximum erasure times deviation value Cmax-Cmin<=Dmax in the system is allowed; When the system needs a new sector, the D value of the current system is judged. When D < the set threshold Dmax, a sector is randomly allocated from the system; when D>= the set threshold Dmax, Cmin is allocated The corresponding sector is used by the system; if the content of the found sector is empty, it is used by the system; if there is valid data in this sector, the valid data will be transferred to other sectors before being used by the system.

Images