JP2003203007A - Nonvolatile area control method for memory of mobile phone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed retrieval method for an unused region to be used next in rewriting nonvolatile information of a mobile phone. <P>SOLUTION: A nonvolatile area includes a plurality of blocks capable of being erased mutually and independently. Each of pages includes a block control region in which block control information indicating use, already used or unused is written, a data region of a plurality of pages in which data is written by the page with a prescribed data amount as one page, and a page control region for retaining page control information indicating unused, effective, and ineffective of each of the pages in the data region. In writing the data in the use block, the unused page is retrieved from the page control information stored in the page control region according to a prescribed retrieval algorithm, and the data is written in the retrieved page. In writing the data in a complete-use block, the effective data of the block is copied in the next unused block, and the complete-use block is erased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for managing a non-volatile area of a memory of a mobile phone, and more particularly to a method for managing a non-volatile area when a flash memory is used as the non-volatile area and a method for quickly searching an unused area in the non-volatile area. .

[0002]

2. Description of the Related Art In a current mobile phone, information input by a user such as a telephone directory is stored in SRAM (Static Random Access Memory). However, SRAM has the advantage that it can be freely read and written as its characteristic,
When the backup battery in the mobile phone runs out, there is a problem that the data cannot be retained. As a result, when the backup battery runs out,
The data stored in the SRAM disappeared and I had to re-enter it.

In order to solve this problem, a flash type EEPROM (hereinafter referred to as FROM) has been used for a memory dial of a mobile phone or the like. FRO
M is not only nonvolatile and can be electrically written / erased, it has low power consumption, and has advantages such as faster access time than a hard disk. For that reason, by backing up the data in the FROM that guarantees data retention, it becomes possible to prevent the problem that the data is lost due to the backup battery running out. However, as is well known, unlike an SRAM, a FROM can write data from bit 1 to bit 0, but cannot write from bit 0 to bit 1. Therefore, when data such as user information data in which 1s and 0s appear indefinitely is written in the FROM, it cannot be partially overwritten. Can not be written. Therefore, in the FROM, erasing the used area and writing new data to the unused area are performed in a chain.

Japanese Patent Application No. 2000-355914 discloses a user setting information management method and a user setting information management when a FROM is used for backing up the user setting information stored in the SRAM when the power of the mobile phone is turned off. The system is described. Hereinafter, this technique is referred to as the first cited technique.

According to this method, the flash memory is
It is divided into multiple blocks that can be erased independently of each other, and each block is divided into a user setting information area where backup setting user setting information is written and a block management area where block management information for each block is written. Split and backup save process (SR
A user setting information history for determining the order in which the processing is performed on the blocks processed by reading the user setting information from the AM and writing it in the flash memory is generated for each block as block management information.

When a trigger for starting a backup program occurs when an event such as power failure occurs, the block management information of all blocks is compared and the block that has undergone the backup saving process first (the earliest) And the block that has undergone the backup save process recently are erased, the block that received the backup save process first is erased, the backup save is executed for the block, and the block management of the block to be erased and backup saved Information is written in the block management area of the block that has been recently backed up and saved.

In this cited technique 1, the block that was subjected to the backup storage processing first is determined to be a used block and is erased, and the block after the erase is determined to be an unused block and the user setting information is written. Is executed. Even if the writing process fails, the user setting information stored in the block that has been recently backed up and stored can be used. Therefore, even if the backup fails, the user setting information will not be lost.

Japanese Unexamined Patent Publication No. 2000-284996 describes a memory management system for a memory, which is not limited to a mobile phone, but in which data is written in a fixed amount of data unit (hereinafter referred to as page). There is. Hereinafter, this technique will be referred to as the second cited technique.

In this method, the memory space on the memory is divided into blocks each having a predetermined size, and an identification table for identifying a used page and an unused page is generated for each block. (In order to facilitate the contrast with the present invention, the “block” and “zone” of the cited technique 2 are referred to as “page” and “block”, respectively.) When accessing the memory, the identification table is While referring to and selecting a block including an unused page, a conversion table for associating a logical address and a physical address of each page in the selected block is generated, and access is performed by referring to the conversion table. Get the physical address that corresponds to the logical address that should be.

As described above, since the conversion table is created only for the block having the unused page, not only the wasteful operation of creating the conversion table for the block not including the unused page is omitted, but also in one block. Since it is only necessary to create the conversion table for a small number of pages, it is possible to obtain the physical address required for writing while suppressing the use of the buffer as much as possible.

[0011]

The above-mentioned first cited technique is cited as an example in which erasing and writing are performed in a chain when a FROM is used. Therefore, this technique is not applied when the FROM is used as a non-volatile area for storing non-volatile information of the memory device, not as a backup memory. The reason is that, for example, mobile device information (for example, ID information, wireless unit adjustment information, device adjustment information, etc.) of a mobile phone is not information that is frequently changed like normal personal information, and is therefore stored in FROM. This is because in such a case, the situation in which information is written to the FROM for each block by one trigger signal is unlikely to occur in such a case as in the cited technique 1.

The above-mentioned second cited technique is a memory management system of a memory when data is written in a fixed amount of data unit (hereinafter referred to as page).
This is a technology that can also be applied to the data writing of.

However, the following problems occur when this technique is actually applied to FROM. As mentioned above, F
Although the writing of the ROM is executed in a chain with the erasing, in the cited technique 2, the erasing is performed in what data amount unit, for example, the erasing is performed in the block unit or in the page unit. It's not clear what.

The management information described in the management table is "used pages" and "unused pages".
The "used page" may be valid (valid page) or invalid data (invalid page) written in the page. It is not clear whether the invalid page should remain invalid or be erased.

Since the cited technique 2 does not include a technique relating to these points, further devising is required to apply this technique to the FROM.

An object of the present invention is to provide a method for managing a nonvolatile memory area of a mobile phone in consideration of erasing processing, and based on this management method, individual nonvolatile information (eg ID information, etc.) of the mobile phone is provided. Another object of the present invention is to provide a high-speed search method for an unused area to be used next when rewriting data in a non-volatile area that stores wireless unit adjustment information, device adjustment information, etc., which is different for each mobile phone terminal.

[0017]

In order to achieve the above object, a method for managing a nonvolatile area of a memory of a mobile phone according to the present invention includes a plurality of blocks that can be erased independently from each other in the nonvolatile area. In each block, data is written page by page with a block management area in which information indicating used, used, and unused of the block is written as block management information, and a predetermined data amount as one page. A data area having a plurality of pages and information indicating that each page in the data area is in an unused state or is in use and the data accumulated in the used page is valid or invalid A page management area to be held as management information is set.

Then, when a plurality of blocks are sequentially used in the rotation number of each block and data is written in the used block, an unused page is searched from the page management information accumulated in the page management area according to a predetermined search algorithm. However, if the unused page is not found as a result of the search by writing the data to the searched page, that is, if the block is a completely used block, the valid data of the block is used as the next unused number of the block. The block is copied to the block and the completely used block after the copying is erased as a used block.

In the process of copying the valid data of the completely used block to the unused block of the next ring number, the valid data to be copied is transferred to the data area of the unused block of the copy destination.
It includes a process of sequentially copying in a predetermined page number order.

In order to perform high speed search, it is desirable to adopt a binary search algorithm as a predetermined search algorithm.

The validity or invalidity of the data stored in the used page is automatically determined according to a preset standard.

The non-volatile area is preferably a predetermined area of the flash memory.

The data stored in the non-volatile area can be non-volatile information of the mobile phone, for example, individual mobile device information such as ID information, radio section adjustment information, device adjustment information and the like. Further, the data stored in the non-volatile area may be data selected by the user of the mobile phone, for example, information that the user does not want to be erased due to power failure or the like.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION According to an embodiment of the present invention, a predetermined area of a memory space of FROM is used as a nonvolatile memory area of a mobile phone, and nonvolatile information such as mobile phone ID information, radio section adjustment information, device adjustment information, etc. is stored. A case of the non-volatile area management method in the case of storing will be described.

FIG. 1 shows a FROM used in a non-volatile area.
It is a figure explaining the structure of the block of an area | region. In the non-volatile area of this embodiment, a plurality of blocks that can be erased independently of each other are set. Each block has
A block management area 1, a page management area 2, and a data area 3 are set. In the block management area 1, information for managing “used”, “used”, and “unused” of the block is written as block management information. In this embodiment, the non-volatile area is 3 blocks,
One byte having a start address of xxFFF0H in the figure is assigned to the block management information for using the three blocks in rotation (turning).

The data area 3 includes a plurality of pages in which nonvolatile data is written page by page with a predetermined data amount as one page. The page number xx described in FIG. 1 represents a memory space for storing nonvolatile information in pages. In this embodiment, a 16-byte data area is set as one page, and the data area 3 is 0000H.
~ It is set to DFFFH (page 3584). (In the figure, for example, xx00100H represents the physical address 00100H of the page of page number xx.) Page management area 2 (xxE000H to x
xFFFFH) holds, as page management information, information indicating whether each page is used or not in the data area. In this embodiment, the information indicating the use is displayed by the valid / invalid information of the accumulated data. Therefore, the page management area 2 manages “unused”, “valid”, and “invalid”. In FIG. 1, for 3584 pages in the data area, 2 bytes are allocated to the page management information of each page. In this embodiment, unused is labeled FFFFH, valid is labeled F0xxH, and invalid is labeled 00xxH.

With respect to a plurality of blocks (3 blocks in the embodiment of FIG. 1), nonvolatile data write blocks (use blocks) are sequentially determined by rotation of each block. The writing of data to the in-use block is performed according to a predetermined search algorithm, and the data is written to the unused page searched by the predetermined search algorithm from the page management information accumulated in the page management area. In this embodiment, a binary search algorithm is used as the predetermined search algorithm.

As a result of the search, when an unused page is not searched, that is, when all pages of the block are written (hereinafter, a block in which all pages are written is referred to as a completely used block). , The valid data of the block is copied to the data area in the unused block in the next rotation order in a predetermined page order. Then, the completely used block is erased as a used block.

In this embodiment, since the binary search is used for the unused page search in the in-use block, the copy of valid data to the next unused block is performed by copying the lowest page number of the unused block at the copy destination. To the page with the highest page number. Alternatively, the copy destination unused blocks are sequentially processed from the highest page number to the lowest page number.

It is desirable that the order of page numbers of valid data copies in the data area of the unused block at the copy destination is determined so as to be convenient for the unused page search algorithm used in the unused block. The reason is that the page layout of valid data copied to the copy destination unused block configures the initial setting value of the unused page search area when the copy destination unused block is used as a used block. is there.

The transition of the above used blocks will be described as follows with reference to FIG.

First, consider a case where pages 0 to 3583 of block 0 are in the non-volatile information writing state and blocks 1 and 2 are in the unused state. At this time, block
0 to 3583 in block 0 when writing non-volatile information next when all 0 areas are used (full use status)
When there are both invalid pages and valid pages, the nonvolatile information is written in the direction in which the page number increases in order from page 0 of block 1, and block 2 is kept unused. In this way, only valid data in block 0 is integrated (copied) into block 1.

When the nonvolatile information write state of pages 0 to 3583 of block 0 is only invalid data, the state of the block becomes used and erase is performed. At this time, the block 1 is in the in-use state in which the nonvolatile information (valid only) is accumulated, and the block 2 is in the unused state.

After erasing block 0, block 0 is unused, block 1 is in use (valid only), and block 2 is unused. Rotation means that after use of block 0, use transitions to block 1, after use of block 1 transitions to use of block 2, and after use of block 2 transitions to use of block 0. , The state of use is to make a ring transition.

When valid data is stored in a page xx and new data having the same information number is written, the currently stored data is invalidated.
The valid / invalid processing is performed as follows.

An information number is assigned to the non-volatile information, and when writing new data of the same information number,
Disable the old data and enable the new data. For example, ID information is xxE000 as valid information in the first state.
When the new ID information is written in the case of being stored in, the new ID information is written in xxE002, the new data is valid and the old data is invalid. That is, the ID information written in xxE000 is invalidated.

In the above embodiment, the validity / invalidity criterion is set to be new or old in terms of time. However, it is of course possible to make the determination based on other standards.
The software recognizes whether the data is valid or invalid. Therefore,
The determination of validity / invalidity can be automated.

Next, the operation of this embodiment will be described.

FIG. 2 shows that after the unused block is determined to be the used block when writing data in the non-volatile area, 2
It is a processing flow which searches an unused page by the minute search method. As a search method, an intermediate address obtained by dividing the page management area by 2 is obtained, and it is determined whether the intermediate address is unused. If it is not used, the search range will be searched for 2 minutes before the intermediate address, and if it is in use, the address after the intermediate address will be searched for 2 minutes, narrowing the search range, and finally, The value divided by 2 is an odd address (since the page management area is 2 bytes), which is 14 in this embodiment.
The search range is narrowed down to (0 × 0E). Then 1
The unused area is determined by checking whether the page management area is unused for each page (page management area is 2 bytes). In FIG. 2, first, the start address (= SA) of the area to be searched is set (step S1). The start address of the page management area is set as the initial value of this start address. Next, the end address of the area to be searched (= E
A) is set (step S2). The end address of the page management area is set as the initial value of this end address. Next, the size of the search area (SIZE = EA-SA) is calculated (step S3). Then divide the size by 2 (S2
= SIZE / 2, step S4). Next, the intermediate address (PA = SA + S2) of the area to be searched is obtained (step S5). Next, it is determined whether or not the PA is 14 (0x0E) (step S6). If the PA is 14 (0x0E), the unused area of the remaining 14 bytes narrowed down by the binary search is searched (step S7), and the binary search processing ends.

According to the judgment in step 6, PA is 14 (0x
If it is larger than 0E, the intermediate address (PA = * PA) is read (step S8). Next, the intermediate address (PA = * P
It is judged whether or not the page A) is unused (step S
9) If not used, set the end address (EA) to the intermediate address (PA) (step S10) and then step S
Return to 3. If the intermediate address (PA) is the used page, the start address (SA) is set to the intermediate address (PA) (step S11), and the process returns to step S3. The process from step S3 to step S10 and step S11 is repeated until PA becomes 14 (0x0E). When PA becomes 14 (0x0E), the process proceeds to step S7, and the process of step S7 ends. Then, the 2-minute search process ends.

In the above-described embodiment, the case where the nonvolatile information of the mobile phone is stored in the nonvolatile area has been described. However, not only the nonvolatile information but also the SRA such as a telephone directory.
Data that you don't want to erase even when M's backup battery runs out,
Even when the data is stored in the non-volatile area by the user setting, similarly, the search for the unused area can be speeded up.

[0042]

As described above, in the present invention, the data area is divided into pages, and the unused, valid, and invalid of each page are managed in the page management area, and the management information is searched for twice. This has the effect of enabling high-speed search.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration of blocks in a FROM area used in a nonvolatile area.

FIG. 2 is a processing flow for searching an unused page by a binary search method.

[Explanation of symbols]

1 block management area 2 page management area 3 data areas

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Claims (7)

[Claims] 1. A method for managing a non-volatile area of a memory of a mobile phone, wherein a plurality of blocks that can be erased independently from each other are set in the non-volatile area, and each block is used, used, or used. A block management area in which information indicating unused is written as block management information, a data area having a plurality of pages in which data is written page by page with a predetermined data amount as one page, and each page in the data area. Set a page management area that holds information indicating that the data accumulated in the used page is valid or invalid, which is in an unused state or a used state, and a page management area. When you use the blocks in order by rotating each block and write data to the blocks, use the specified search algorithm. According to the gorism, an unused page is searched from the page management information accumulated in the page management area, data is written to the searched page, and when the unused page is not searched as a result of the search, that is, the block Is a completely used block, the valid data of the block is copied to an unused block of the next wheel number, and the copied block is erased as a used block. Non-volatile area management method. 2. The process of copying the valid data of a completely used block to an unused block of the next ring number, the valid data to be copied is sequentially copied to the data area of the unused block of the copy destination in order of a predetermined page number. The method of claim 1 including processing. 3. The method of claim 1, wherein the predetermined search algorithm is a binary search algorithm. 4. The method according to claim 1, wherein the validity or invalidity of the data stored in the used page is automatically determined according to a preset standard. 5. The method of claim 1, wherein the non-volatile area is a predetermined area of flash memory. 6. The method according to claim 5, wherein the data stored in the non-volatile area includes non-volatile information of the mobile phone. 7. The method of claim 5, wherein the data stored in the non-volatile area includes data selected by a user of the mobile phone.