JP2007199985A - Rewriting device and rewriting method for nonvolatile memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rewriting device and a rewriting method for a nonvolatile memory, capable of reducing a time necessary for rewriting processing. <P>SOLUTION: When executing the rewriting processing of a flash memory 28 by repeating writing of download data and erasure of already written data with each sector 29 of the flash memory 28 as a sequential processing target, a checksum table 28A showing a checksum of the already written data of each sector 29 is stored in the flash memory 28, a checksum table 34C of the download data 34 produced in a storage capacity unit corresponding to each sector 29 is acquired, the checksum table 28A and a checksum table 34C corresponding to each sector 29 are compared, the execution of the writing and the erasure with the sector 29 decided that a value accords as the processing target is eliminated, and the checksum table 28A is updated every time the rewriting processing is executed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rewriting device and a rewriting method for a nonvolatile memory capable of rewriting data.

  Non-volatile memories whose data is rewritten include various memories such as a flash memory, an EEPROM (Electric Erasable Programmable Read Only Memory), and an FeRAM (Ferro Electric Random Access Memory).

  In these non-volatile memories, when data is rewritten, the written data in the write target area is once erased, and then new data is written.

  For example, the rewrite process in the flash memory is executed in units of sectors, and the erase and write processes are executed for all sectors in the write target area.

  For this reason, the rewrite process is executed by erasing and writing all data regardless of the value of the new data. Therefore, if the capacity of the new data to be written to the nonvolatile memory is large, the rewrite process is performed. It takes a long time.

As a technique applicable to this problem, conventionally, in order to shorten the sector erasing time and data writing time of the flash memory, the sector erasing process before the writing to the sector in which the written data before the rewriting process is the value of the erasure state That the new data to be written is a value in the erased state is not executed (see, for example, Patent Document 1).
JP 2001-297589 A

  However, in the technique described in Patent Document 1, at least the erasing process is executed regardless of the data value after writing for a sector whose data value before writing is not an erasure state value. There was a problem that it could not be shortened.

  The present invention has been made to solve the above-described problems, and an information processing apparatus and an information processing method capable of shortening the time required for the rewriting process by omitting the rewriting process according to the contents of written data and new data Is the purpose.

  In order to solve the above problem, the invention according to claim 1 is directed to erasing written data by sequentially processing each of a plurality of divided areas obtained by dividing a storage area of a nonvolatile memory in a predetermined storage capacity unit. And a non-volatile memory rewriting device that executes rewriting processing of the non-volatile memory by repeating unit processing for writing new data, and is updated each time the rewriting processing is executed, Storage means for storing a check table for the written data, acquisition means for acquiring the check table for the new data created in the predetermined storage capacity unit, and a check table for the new data acquired by the acquisition means Is compared with the check table of the written data stored in the storage means. Judging means for judging whether or not for each of the segmented region, when it is determined that the matching by the determining unit, and a, a skip unit is omitted execution of the unit processing the segmented region processed.

  According to the first aspect of the present invention, erase of written data and writing of new data are performed sequentially for each of a plurality of divided areas obtained by dividing the storage area of the nonvolatile memory by a predetermined storage capacity unit. When executing the rewriting process of the nonvolatile memory by repeating the unit process to be performed, the check table of the written data is stored in the storage unit in each of the divided areas, and is created in the predetermined storage capacity unit. The new data check table is obtained, and the new data check table and the written data check table stored in the storage unit are compared to determine whether or not they match for each of the divided regions. The rewriting process is performed by omitting the execution of the unit process for the segmented area determined to match. Since updating the check table stored in the storage means each time it is executed, it is possible to shorten the time required to rewrite processing by omitting the rewrite process according to the contents of the written data and the new data.

  That is, the present invention prepares a check table for written data and a check table for new data, executes unit processing for different partitioned areas of the check table, and executes unit processing for partitioned areas that match the check table. Is omitted.

  As the check table, a checksum of data in a predetermined storage capacity unit can be applied.

  Further, according to the present invention, as in the second aspect of the present invention, when the unit process is completed and when the unit process is omitted by the omitting means, the identification information of the segmented area to be processed A non-volatile storage means for updating and storing, and when the execution of the rewriting process is interrupted, the unit process is executed on the unprocessed segmented area based on the information stored in the non-volatile storage means Thus, a resumption means for resuming the rewriting process may be provided.

  Further, according to the present invention, the predetermined storage capacity may be a minimum unit that can execute the unit processing. Note that the minimum unit that can execute the unit processing is determined based on the type and specification of the nonvolatile memory.

  On the other hand, in order to solve the above-mentioned problem, the invention according to claim 4 is the data already written by sequentially processing each of the plurality of divided areas obtained by dividing the storage area of the nonvolatile memory by a predetermined storage capacity unit. A non-volatile memory rewriting method for executing rewriting processing of the non-volatile memory by repeating unit processing for erasing data and writing new data, and storing the check table of the written data in each of the divided areas And storing the new data check table created in the predetermined storage capacity unit, and the new data check table and the written data check table stored in the storage means. Whether or not they match is determined for each of the partitioned areas, and the partitioned areas determined to match are processed Omit the execution of the unit processing the elephants, and updates the check table stored in the storage means every time the rewriting process is executed.

  According to the invention described in claim 4, since it operates in the same manner as the nonvolatile memory rewriting device described in claim 1, as in the invention described in claim 1, the rewriting process is performed according to the contents of written data and new data. By omitting, the time required for the rewriting process can be shortened.

  As described above, the present invention is a unit for erasing written data and writing new data for each of a plurality of divided areas obtained by dividing a storage area of a nonvolatile memory in a predetermined storage capacity unit. When executing the rewriting process of the nonvolatile memory by repeating the process, the check table of the written data is stored in the storage means in the respective divided areas, and the new data created in the predetermined storage capacity unit is stored. A data check table is obtained, and the new data check table and the written data check table stored in the storage unit are compared to determine whether or not they match for each of the partitioned areas. Then, the execution of the unit process with the determined segmented area as a processing target is omitted, and the rewriting process is performed. Since the check table stored in the storage means is updated each time the data is executed, the time required for the rewriting process can be shortened by omitting the rewriting process according to the contents of written data and new data. Have

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a schematic diagram showing a configuration of a data rewriting device 10 according to the present embodiment. Hereinafter, a schematic configuration of the data rewriting device 10 will be described.

  As shown in the figure, the data rewrite device 10 includes an I / F 24 and is connected to a personal computer (PC) 12 via a communication medium.

  Note that as a communication medium, in addition to a cable for performing wired communication, infrared rays, radio waves, and the like for performing wireless communication represented by Bluetooth (Infrared Data Association) standards and the like can be applied.

  The data rewriting device 10 includes a CPU (Central Processing Unit) 20 that controls the operation of the entire device, a memory 22 that includes a RAM (Random Access Memory) in the data rewriting device 10, the I / F 24, and the input / output The memory 22 and the input / output control unit 26 are each connected to the CPU 20, and the I / F 24 is connected to the input / output control unit 26.

  The input / output control unit 26 temporarily holds download data input via the I / F 24 and outputs it according to instructions from the CPU 20.

  The data rewrite device 10 includes a flash memory 28 and an NVM (non-volatile memory) 30, and the flash memory 28 and the NVM 30 are connected to the CPU 20, respectively.

  In addition, the CPU 20 temporarily stores the download data output from the input / output control unit 26 in the memory 22 and executes data rewrite processing on the flash memory 28 using the download data.

  FIG. 2 schematically shows the configuration of the flash memory 28. As shown in the figure, the flash memory 28 is divided into a plurality of sectors 29 for each predetermined storage capacity, and data can be erased and written in units of each sector 29.

  Each sector 29 is given an identification code (in the present embodiment, an integer from 1 to N), and the sector can be specified by the identification code.

  The CPU 20 sets an area to be rewritten based on the download data in units of sectors, executes an erase process for temporarily erasing written data written in each sector, and then executes a write process based on the download data. Execute data rewrite processing.

  By the way, in this embodiment, the written data of each sector and the downloaded data are compared, and if they match each other, the data rewriting process is omitted.

  Therefore, a checksum table 28 A as shown in FIG. 3 is stored in the flash memory 28. The checksum table 28A stores a checksum of written data for each sector. The checksum table 28 </ b> A is updated and stored by the CPU 20 every time rewriting processing is performed on the flash memory 28.

  FIG. 4 schematically shows an example of the data structure of the download data 34. The download data 34 shown in the figure is downloaded when the firmware stored in the flash memory 28 is rewritten.

  As shown in the figure, in the present embodiment, the download data 34 includes a ROM image 34B as a firmware main body, and an emergency downloader 34A including a program that can execute the minimum necessary functions of the firmware main body. The checksum table 34C of the download data 34 is included.

  As shown in FIG. 5, the checksum table 34 </ b> C of the download data 34 includes the divided data obtained by dividing the data of the emergency downloader 34 </ b> A and the ROM image 34 </ b> B by the storage capacity unit of each sector of the flash memory 28. Is stored in the checksum. “Data No.” shown in the figure indicates the order of the divided data.

  When executing the rewrite process, the CPU 20 sequentially compares the checksum table 28A stored in the flash memory 28 with the corresponding checksum in the checksum table 34C included in the download data 34, and the sector in which both match. The rewriting process is omitted for.

  That is, for example, if it is assumed that the checksums of the sectors 29 indicated by the fill in FIG. 2 do not match, the rewriting process may be executed only for the sectors 29 indicated by the fill. In firmware update or the like, since a part of written data is often changed, the number of sectors 29 whose checksums do not match is particularly small, and the processing time is greatly shortened.

  Further, in this embodiment, when the rewriting process of the download data is interrupted halfway due to a power failure or trouble, the rewriting process is resumed with a sector that has not been processed being processed.

  Therefore, the NVM 30 stores the sector number of the sector 29 for which the rewriting process is completed. (1-N) and data No. of download data 34. A processing counter for storing (1 to M) is stored. The stored contents of the processing counter are updated by the CPU 20 as the rewriting process proceeds.

  Hereinafter, the operation of the present embodiment will be described.

  FIG. 6 shows a flow of processing of a rewrite processing program executed by the CPU 20 when communication between the data rewriting device 10 and the PC 12 is started. Hereinafter, the rewriting process according to the present embodiment will be described with reference to FIG.

  First, in step 200, the download data 34 is received, and in the next step 202, a checksum table 28A of written data stored in the flash memory 28 is obtained.

  Here, the download data 34 is received by temporarily holding the download data input via the I / F 24 in the input / output control unit 26 and storing it in the memory 22.

  In the next step 204, the initial unit data No. of the download data 34 is set as the initial value of the processing counter of the NVM 30. 1 and the sector number of sector 29 in which corresponding data is stored. (1 to N) is set, and then the process proceeds to step 206. If the corresponding data does not exist, the sector number of the unused sector 29 is set. Etc. may be set.

  In step 206, the data and sector corresponding to the value of the processing counter are set as processing targets, and then the process proceeds to step 208. In step 208, the checksum corresponding to the processing target of the checksum table 34C of the download data 34 and the checksum table 28A of the flash memory 28 is compared, and then the process proceeds to step 210.

  In Step 210, it is determined whether or not the checksums match as a result of the comparison. If the determination is negative, the process proceeds to Step 212. In step 212, data erasure processing is performed on the sector 29 to be processed, and then the process proceeds to step 214 to execute data write processing on the sector 29 on which erasure processing has been performed. The process proceeds to step 216.

  On the other hand, if the determination in step 210 is affirmative, it is determined that the written data and the downloaded data match, and the process proceeds to step 216 without executing the processes in steps 212 and 214.

  In step 216, it is determined whether or not all data has been processed. If the determination is negative, the process proceeds to step 218. After updating the process counter, the process proceeds to step 206 again.

  On the other hand, if the determination in step 216 is affirmative, the process proceeds to step 220, where the checksum table is updated and the rewriting process is terminated.

  As a result, the erasure process and the write process are not executed on the sector 29 having the same storage contents before and after the rewriting, and therefore the rewriting can be executed with a shortened processing time.

  Even when the rewrite process is interrupted due to a power failure or the like, the process counter of the NVM 30 stores how far the process has been completed, so the sector 29 that has not been processed based on the process counter is targeted. The rewriting process can be executed.

  FIG. 7 shows the flow of processing of the rewrite processing program executed by the CPU 20. Hereinafter, the re-writing process according to the present embodiment will be described with reference to FIG.

  First, in step 240, the download data 34 is received again, and in the next step 242, the checksum table 28A of the written data stored in the flash memory 28 is acquired.

  The download data 34 is re-received by temporarily holding the download data input via the I / F 24 in the input / output control unit 26 and storing it in the memory 22.

  In the next step 244, the value of the processing counter of the NVM 30 is acquired, and then the process proceeds to step 246, and the data and sector corresponding to the value of the processing counter are processed, and then the process proceeds to step 248.

  In step 248, the checksum corresponding to the processing target of the checksum table 34C of the download data 34 and the checksum table 28A of the flash memory 28 is compared, and then the process proceeds to step 250.

  In step 250, it is determined whether the checksums match as a result of the comparison. If the determination is negative, the process proceeds to step 252. In step 252, data erasure processing is executed for the sector 29 to be processed, and then the process proceeds to step 254 to execute data write processing to the sector 29 subjected to erasure processing. The process proceeds to step 256.

  On the other hand, if the determination in step 250 is affirmative, it is determined that the written data and the downloaded data match, and the process proceeds to step 256 without executing the processing in steps 252 and 254.

  In step 256, it is determined whether or not all data has been processed. If the determination is negative, the process proceeds to step 258, and after updating the process counter, the process proceeds to step 246 again.

  On the other hand, if the determination in step 246 is affirmative, the process proceeds to step 260 where the rewriting process is terminated after updating the checksum table.

  Thus, in the rewriting process, since the rewriting process is executed from the sector 29 where the rewriting process was interrupted last time, the time required for the rewriting can be shortened.

  As described in detail above, according to the present embodiment, the flash memory 28 is rewritten by repeatedly erasing written data and writing downloaded data for each sector 29 of the flash memory 28 sequentially. At this time, a checksum table 28A indicating the checksum of the written data of each sector 29 is stored in the flash memory 28, and a checksum table 34C of the download data 34 created in the storage capacity unit corresponding to each sector 29 is stored. And the checksum table 34C of the download data 34 and the checksum table 28A of the written data are compared to determine whether or not they match each other, and the sector 29 determined to match is processed. Targeted erase and write Omit the line, so to update the checksum table 28A each time the rewriting process is performed, it is possible to shorten the time required to rewrite processing by omitting the rewrite process according to the contents of the written data and the new data.

  Further, according to the present embodiment, when the erasing and writing processes are completed and when the processes are omitted, the sector number of the sector 29 to be processed is set. If the processing counter is provided in the NVM 30 that is updated and stored, and the execution of the rewriting process is interrupted, the rewriting process is executed on the unprocessed sector 29 based on the processing counter of the NVM 30. Even when is interrupted, the time required for rewriting can be shortened.

  In this embodiment, the checksum table 34C of the download data 34 has been described as being included in a part of the download data 34C. However, the present invention is not limited to this.

  For example, the checksum table data may be input separately from the download data 34, or the checksum table may be generated based on the download data by a program or the like.

  In the present embodiment, the checksum table is created in units of sectors 29 and the rewrite process is executed. However, the present invention is not limited to this, and a block unit composed of a plurality of sectors 29 is used. You may make it perform a process by.

  That is, the unit for executing the processing (corresponding to “predetermined storage capacity” in the claims) is the time required for comparing the checksum tables and the erasing and writing processing (“unit processing” in the claims). It can be determined as appropriate in consideration of the time required.

  Furthermore, the configuration (see FIG. 1) of the data rewrite device 10 according to each of the above embodiments is an example, and can be changed as appropriate without departing from the spirit of the present invention.

  Further, the processing flow (see FIGS. 6 and 7) according to each of the above embodiments is also an example, and can be appropriately changed without departing from the gist of the present invention.

It is the schematic which shows the structure of the data rewriting apparatus which concerns on embodiment. 1 is a schematic diagram schematically showing a configuration of a flash memory according to an embodiment. It is a schematic diagram which shows the checksum data stored in the flash memory which concerns on embodiment. It is explanatory drawing which shows typically the download data which concern on embodiment. It is a schematic diagram which shows the checksum data contained in the download data which concerns on embodiment. It is a flowchart which shows the flow of a process of the rewriting process program which concerns on embodiment. It is a flowchart which shows the flow of a process of the rewriting process program which concerns on embodiment.

Explanation of symbols

10 Data rewrite device 12 PC
20 CPU (determination means, omission means, resumption means)
22 memory 24 I / F
26 Input / output control unit (acquisition means)
28 Flash memory (memory means)
29 sectors (partition area)
30 NVM (non-volatile storage means)

Claims (4)

By repeating unit processing for erasing written data and writing new data for each of a plurality of partitioned areas obtained by partitioning the storage area of the nonvolatile memory in a predetermined storage capacity unit, the nonvolatile memory A non-volatile memory rewriting device for executing a memory rewriting process,
Updated each time the rewriting process is executed, and storage means for storing a check table of the written data in each of the partitioned areas;
Obtaining means for obtaining a check table of the new data created in the predetermined storage capacity unit;
A determination unit that determines whether the check table of the new data acquired by the acquisition unit and the check table of the written data stored in the storage unit match each other for each of the divided regions;
An omission means for omitting the execution of the unit process with the segmented area as a processing target when it is determined by the determination means to be matched;
Non-volatile memory rewriting device comprising: A non-volatile storage unit that updates and stores identification information of the segmented region to be processed when the unit process is completed and when the unit process is omitted by the omitting unit;
When the execution of the rewriting process is interrupted, a resuming unit that executes the unit process for the unprocessed segmented area based on information stored in the nonvolatile storage unit and resumes the rewriting process When,
The nonvolatile memory rewriting device according to claim 1, further comprising:   3. The nonvolatile memory rewriting device according to claim 1, wherein the predetermined storage capacity is a minimum unit capable of executing the unit processing. By repeating unit processing for erasing written data and writing new data for each of a plurality of partitioned areas obtained by partitioning the storage area of the nonvolatile memory in a predetermined storage capacity unit, the nonvolatile memory A non-volatile memory rewriting method for executing a memory rewriting process,
A check table of the written data is stored in the storage means in each of the divided areas,
Obtain a check table of the new data created in the predetermined storage capacity unit,
Comparing the check table of the new data and the check table of the written data stored in the storage means to determine whether or not they match for each of the divided areas;
Omit execution of the unit process for the segmented area determined to match,
Update the check table stored in the storage means each time the rewriting process is executed,
Non-volatile memory rewrite method.

Images