CN114360627A

CN114360627A - Lightweight TF card detection tool

Info

Publication number: CN114360627A
Application number: CN202011085587.2A
Authority: CN
Inventors: 汪凯
Original assignee: Hefei Ingenic Technology Co ltd
Current assignee: Hefei Ingenic Technology Co ltd
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2022-04-15

Abstract

The invention provides a lightweight TF card detection method, which comprises the following steps: s1, detecting the card capacity, namely obtaining the number of large and small sectors of a file system and the number of bytes of each sector by obtaining the basic information of the DBR to calculate the card capacity; s2, carrying out capacity expansion detection, namely determining whether the TF has a capacity expansion phenomenon or not by judging whether the reading and writing of the capacity of the whole disk are feasible or not; s3, detecting file information, and scanning a root directory area to obtain a file head cluster; or performing first cluster positioning for multiple levels of subdirectories, and reading the file content by taking the first cluster positioning as a starting point; and S4, detecting the bad block, performing read-write proofreading on the TF card by using the read command, determining the information of the wrong cluster, positioning the wrong information, and marking the area of the bad block which cannot be recovered. Through the light-weight TF card detection method, the existence, the capacity size, the capacity expansion detection, the file information detection, the bad block scanning, the reading and writing speed test, the number and the size of the FAT tables and other related information of the TF card can be rapidly detected.

Description

Lightweight TF card detection tool

Technical Field

The invention relates to the technical field of detection, in particular to a light-weight TF card detection tool.

Background

With the rapid development of information technology, electronic products are more and more popular, and the development of the products benefits from the rapid development of embedded system technology, such as application of a camera, a mobile phone and the like. The TF card equipment is also widely applied to embedded equipment, and the TF card detection methods are various.

The current TF card detection tools include the following:

TF card detection tool of PC end: the device can only run at the PC end, has more functions but larger volume and low portability.

The existing embedded TF card detection tool: the method can basically realize the TF card detection in the embedded system, but has single function and does not meet the requirements of various manufacturers.

The existing TF detection tool at the PC end is based on a graphical operation interface of a Windows operation system, is too large in size, is only suitable for a PC machine, and cannot be suitable for various platforms of an embedded system. The existing TF detection tool basically realizes TF card detection in an embedded system, but cannot display various detection data of the TF card in real time through a terminal, and cannot meet various requirements of different manufacturers.

Furthermore, technical terms commonly used in the art include:

the TF card is also called a T-Flash card, and has the full name: TransFlash, also known as: micro SD, co-developed by motorola with sandis k, was introduced in 2004. Is a microminiature card (11 x 15 x 1MM), about 1/4 of the SD card, which can be counted as the smallest storage card at present.

Light weight: it means that the scale is smaller, but the function is more perfect.

Capacity expansion card: the method is characterized in that the capacity of the memory card with small capacity is increased by illegal means (software) (for example, the capacity of the memory card with small capacity is 128G of 8G), and the increased memory can not be normally used. Fat (file Allocation table): this means "file allocation table". It is a table for recording the location of the file, which is very important for the use of the hard disk, and if the file allocation table is lost, the data on the hard disk cannot be located and cannot be used.

Clustering: the amount of data per operation when writing data to or reading data from a disk is called a data unit, and its size is determined when a file system is built. Consists of a number of sectors, which is the minimum unit of access data.

Sector: each track on the disk is equally divided into a number of arc segments, which are sectors of the disk. Each sector is 512 bytes in size. Sectors are numbered starting with a "1".

DOS Boot Record, the first sector that an operating system can access after entering a file system, typically to interpret the file system, the DBR (Boot sector), which is the program segment loaded by the MBR of the hard disk. After the DBR is loaded into memory, the boot segment begins executing, its main function is to complete the boot of the operating system and give control to the operating system. Each partition has a boot sector, but only the partition set as active will be operated by the MBR-loaded DBR-in-memory.

MBR: the master boot record, which takes 446 bytes, is the code that is first loaded into memory and executed from the bootable medium after the computer is booted, and is typically used to interpret the partition structure.

Disclosure of Invention

The invention aims to be built in an embedded system, and has multiple functions and light weight. And the method has higher portability and is compatible with different manufacturers in each embedded system. Through the light-weight TF card detection method, the existence, the capacity size, the capacity expansion detection, the file information detection, the bad block scanning, the reading and writing speed test, the number and the size of the FAT tables and other related information of the TF card can be rapidly detected.

Specifically, the method provides a lightweight TF card detection method, which comprises the following steps:

s1, detecting the card capacity, namely obtaining the number of large and small sectors of a file system and the number of bytes of each sector by obtaining the basic information of the DBR to calculate the card capacity;

s2, carrying out capacity expansion detection, namely determining whether the TF has a capacity expansion phenomenon or not by judging whether the reading and writing of the capacity of the whole disk are feasible or not;

s3, detecting file information, and scanning a root directory area to obtain a file head cluster; or performing first cluster positioning for multiple levels of subdirectories, and reading the file content by taking the first cluster positioning as a starting point;

and S4, detecting the bad block, performing read-write proofreading on the TF card by using the read command, determining the information of the wrong cluster, positioning the wrong information, and marking the area of the bad block which cannot be recovered.

In the step S1, the MBR is skipped to the DBR to obtain specific DBR data, and the total number of sectors of the file system, which is represented by four bytes of 0x 20-0 x23, can be obtained by referring to the structure of the FAT file system; two bytes from 0x0b to 0x0c result in the number of bytes per sector, i.e., the card capacity is the total number of sectors by the number of words per sector.

In step S2, in combination with the calculation algorithm of the card capacity in step S1, the method for expanding the capacity of the memory card specifically includes the steps of:

A. by comparing the memory capacity of the sector with the memory capacity of the CID register,

B. data read-write comparison at a range of addresses of card capacity,

C. data read and write at random addresses in a high address range,

and detecting whether the capacity of the memory card is expanded or not in total three steps, and judging the memory card which is not expanded normally only if the three steps of detection are normal, thereby realizing the capacity expansion detection of the memory card.

In the step S3, since the FAT area immediately follows the file system reserved area, the position of the FAT1 in the file system can be obtained by "the reserved sector number" at an offset of 0x0E to 0x0F bytes in the boot record. FAT2 immediately follows FAT1, and its position can be calculated from the position of FAT1 plus the number of large sectors of the FAT table.

When a file is newly built in a file system, if the newly built file only occupies one cluster, an end mark is written in an FAT table entry corresponding to the cluster allocated to the newly built file; if the newly-built file only occupies one cluster, writing the cluster number of the next cluster allocated to the newly-built file in the FAT table entry corresponding to each cluster occupied by the newly-built file, and writing an end mark in the FAT table image corresponding to the last cluster;

the initial cluster number of a file is recorded in the directory entry of the file, and other clusters of the file are recorded in the FAT table by using a cluster chain structure; if the next cluster of a file is to be searched, only the FAT table entry corresponding to the starting cluster number described in the directory entry of the file needs to be checked, and if the file only has one cluster, the value is an end mark; if the file has more than one cluster, the value here is the cluster number of its next cluster.

All clusters in the area actually used for storing user data in the data area are numbered from 2, that is, the starting position of cluster number 2 is the starting position of the data area, and the data starting position of a FAT32 file system is located, which can be calculated by the relevant parameters of the boot sector:

H. obtaining reserved sectors from the offset of the pilot sector, 0x 0E-0 x0F bytes;

I. obtaining the number of the FAT table from the offset of 0x10 bytes;

J. obtaining the number of large and small sectors of each FAT table from the offset of 0x 24-0 x27 bytes;

K. calculated using the following formula: reserving the number of sectors plus the number of the sectors with the size of each FAT table multiplied by the number of the FAT tables, which is the number of the initial sectors of the data area;

to calculate the sector number of other known cluster numbers, the number of sectors per cluster size is found at the offset of 0x0D bytes of the boot sector and is calculated using the following formula:

the number of the start sector of a certain cluster is the number of reserved sectors + the number of large and small sectors of each FAT table × the number of FAT tables + (cluster number-2) of the cluster × the number of sectors of each cluster.

In step S4, if a cluster has a bad sector, the whole cluster will be marked as a bad cluster by the FAT table entry value 0xFFFFFF7, and will not be used any more, and this bad cluster mark is recorded in the corresponding FAT table entry and displayed in the terminal.

In summary, the method of the present application can achieve the following advantages: the light TF card detection method is suitable for the performance attribute test of the multifunctional TF card of the embedded system. The method can realize the quick detection of the existence of the TF card, the capacity size, the capacity expansion detection, the file information detection, the bad block scanning, the read-write speed test, the number and the size of the FAT tables and other related information.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a flowchart of a program to which the present detection method is applied.

Figure 2 is a schematic diagram of MBR and DBR structures.

FIG. 3 is a schematic diagram of the memory structure of the present invention.

Fig. 4 is a flow chart of the method of the present invention.

Detailed Description

In order that the technical contents and advantages of the present invention can be more clearly understood, the present invention will now be described in further detail with reference to the accompanying drawings.

As shown in fig. 4, the present application is a method for detecting a lightweight TF card, the method comprising the following steps:

In particular, the detection method can be written in the C language. Has higher applicability and is convenient to be transplanted on different platforms. The method comprises the following steps: detecting the card capacity, namely obtaining the number of sectors with the size of a file system and the number of bytes of each sector by obtaining the basic information of a DBR (boot sector) to calculate the card capacity; capacity expansion detection, namely determining whether the TF has capacity expansion phenomenon or not by judging whether the read-write of the capacity of the whole disk is feasible or not; and detecting file information, wherein a file head cluster can be obtained by scanning the root directory area. Or the first cluster location is performed for multiple levels of subdirectories, and the file content can be read by taking the first cluster location as a starting point. The specific program flow chart is shown in fig. 1:

firstly, opening a device file;

secondly, reading file system information;

thirdly, reading the FAT table;

fourthly, scanning the content of the FAT table;

fifthly, calculating the state of the card by reading the information;

sixthly, the terminal displays data;

and finally, ending.

The following is a specific scheme of the TF detection method:

detection of card capacity: as can be known from FIG. 2 and FIG. 3, the specific DBR data obtained by jumping from the MBR to the DBR can be obtained, and the total number of sectors of the file system represented by four bytes of 0x 20-0 x23 can be obtained by referring to the structure of the FAT file system. 0x0 b-0 x0c total two bytes to get the number of bytes per sector. I.e. card capacity-total number of sectors-words per sector.

Capacity expansion detection: combining with the calculation algorithm of card capacity, aiming at the current memory card capacity expansion method, the sector memory capacity and the CID register memory capacity are compared. And comparing the data read-write of the address in the range of the card capacity, and reading and writing the data of the random address in the high address range. And detecting whether the capacity of the memory card is expanded or not in total three steps, and judging the memory card which is not expanded normally only if the three steps of detection are normal, thereby realizing accurate and effective capacity expansion detection of the memory card.

File information detection: as can be seen from fig. 3, since the FAT area immediately follows the file system reserved area, the position of the FAT1 in the file system can be obtained by "the number of reserved sectors" at an offset of 0x 0E-0 x0F bytes in the boot record. FAT2 immediately follows FAT1, and its position can be calculated from the position of FAT1 plus the number of large sectors of the FAT table.

When a file is newly created in a file system, if the newly created file only occupies one cluster, an end mark will be written into the FAT entry corresponding to the cluster allocated to the newly created file. If the newly-created file does not only occupy one cluster, writing the cluster number of the next cluster allocated to the newly-created file into the FAT table entry corresponding to each cluster occupied by the newly-created file, and writing an end mark into the FAT table entry corresponding to the last cluster. The starting cluster number of a file is recorded in its directory entry, and the other clusters of the file are recorded in the FAT table using a cluster chain structure. If the next cluster of a file is to be searched, only the FAT table entry corresponding to the starting cluster number described in the directory entry of the file needs to be checked, and if the file only has one cluster, the value is an end mark; if the file has more than one cluster, the value here is the cluster number of its next cluster.

The data area is actually used to store all clusters of the area for user data, numbered from 2. That is, the start position of cluster No. 2 is the start position of the data area. Locating the start of the data of a FAT32 file system can be calculated from the parameters associated with the boot sector.

1. Reserved sectors are obtained from the pilot sector at offsets 0x 0E-0 x0F bytes.

2. The number of FAT tables is obtained from the offset 0x10 bytes.

3. The number of large sectors per FAT table is obtained from the offset of 0x 24-0 x27 bytes.

4. Calculated using the following formula: the reserved sector number + the size of each FAT table and the number of the FAT tables are equal to the initial sector number of the data area

And (3) bad block testing: reading and writing proofreading a plurality of clusters of the TF card by using a reading command, determining information of an error cluster, positioning the error information, marking an unrecoverable bad block area, if a bad sector exists in a certain cluster, marking the whole cluster as a bad cluster by using a FAT table entry value of 0xFFFFFF7, and not using the bad cluster, wherein the bad cluster mark is recorded in a corresponding FAT table entry and displayed in a terminal.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightweight TF card detection method, characterized in that the method comprises the following steps:

2. The method according to claim 1, wherein in step S1, the MBR is shifted to the DBR to obtain specific DBR data, and the total number of sectors of the file system, which is represented by four bytes from 0x20 to 0x23, is obtained by referring to the structure of the FAT file system; two bytes from 0x0b to 0x0c result in the number of bytes per sector, i.e., the card capacity is the total number of sectors by the number of words per sector.

3. The method according to claim 1, wherein in step S2, in combination with the calculation algorithm for card capacity in step S1, for the memory card capacity expansion method, the steps specifically include:

B. data read-write comparison at a range of addresses of card capacity,

C. data read and write at random addresses in a high address range,

4. The method according to claim 1, wherein in step S3, since the FAT area immediately follows the reserved area of the file system, the position of the FAT1 in the file system can be obtained by "reserved sector number" at an offset of 0x 0E-0 x0F bytes in the boot record. FAT2 immediately follows FAT1, and its position can be calculated from the position of FAT1 plus the number of large sectors of the FAT table.

5. The method for detecting a lightweight TF card according to claim 4,

6. A light-weight TF card detection method according to claim 5, wherein all clusters of the area for storing user data in the data area are numbered from 2, i.e. the starting position of cluster number 2 is the starting position of the data area, locating the data start of a FAT32 file system can be calculated by the related parameters of the boot sector:

I. obtaining the number of the FAT table from the offset of 0x10 bytes;

7. The method for detecting a lightweight TF card according to claim 1,