JP6060892B2 - In-vehicle data storage device and data storage method - Google Patents

Description

The present invention relates to a vehicle mounting a data storage device and data storage way to store data in a nonvolatile memory such as a flash memory in which data for each block are collectively erased.

  2. Description of the Related Art Conventionally, flash memories are widely used for data storage in electronic devices mounted on vehicles, for example. The flash memory is a nonvolatile memory and has an advantage of a large data storage capacity. However, the flash memory has the disadvantages that it is necessary to erase data for each block of a predetermined size and that the number of rewritable times is small compared to a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory). is there.

  Patent Document 1 proposes a data storage device that does not cause data loss or damage even when a power interruption occurs. This data storage device sequentially writes data to a plurality of storage blocks of a flash memory, and performs block update processing for copying valid data to the next block when changing the data write destination. In the first storage block to be written first, three pieces of information of an update start bit, an update end bit, and an erase end bit are stored for each storage block. The data storage device sets the update start bit to “0” before the start of the block update process, and sets the update end bit to “0” after the block update process ends. Further, the data storage device performs the erasure process of the storage block in which the update end bit is set to “0”, and sets the erase bit to “0” after the end of the erase process.

JP 2011-175361 A

  The flash memory needs to erase data for each block. For this reason, when a block is filled by writing data, the data must be erased after saving necessary data from this block to another block. However, writing data to the flash memory may rarely fail, and there is a risk of data corruption due to the failure. Some of the data stored in the flash memory is such that, for example, the device identification information or setting values are not updated after they are written before factory shipment. It is necessary to save such non-updated data to another block when performing erasure processing on the block. However, if data is damaged when writing to another block, this data is restored. There was a problem that there was no art.

  In addition, since the flash memory has a small number of rewritable times, the possibility of data writing failure increases when the number of times of rewriting reaches or exceeds the upper limit by repeatedly writing, saving, and erasing data. For this reason, there is a problem that the reliability of data is lowered by repeatedly saving data even for data that is not updated as described above.

The present invention has been made in view of such circumstances, and the object of the present invention is that data that is not updated (or that is updated less frequently) is damaged and trusted as data is erased for each block. and to provide a vehicle mounting data storage device and data storage method that obtained prevents sexual decrease or the like occurs.

An in-vehicle data storage device according to the present invention includes a nonvolatile memory having a plurality of storage blocks mounted on a vehicle and from which data is erased collectively. When one storage block is filled with data by the first writing means to be performed and the data writing by the first writing means, one or a plurality of data is read from the one storage block and the other A plurality of storage blocks included in the non-volatile memory, comprising: a data copying means for writing to the storage block; and an erasing means for erasing data of the one storage block after the processing by the data copying means is completed. , A data erasure prohibition block not to be processed by the first writing unit, the data copying unit, and the erasing unit, and the first A plurality of data erasure permission blocks to be processed by the writing means, the data copying means, and the erasing means, and writing data to the data erasure prohibition block until the data erasure prohibition block is filled with data The data erasure prohibiting block further stores information related to the specification of the vehicle mounted thereon, and the first writing unit is mounted on the vehicle. With respect to the electronic device, setting information that can be changed by a user of the vehicle is written, and the second writing means writes information about security.

In the in- vehicle data storage device according to the present invention, when the first writing unit writes one data to the data erasure permission block, the one data and a copy data of the one data And detecting means for detecting an error in the data written in the non-volatile memory, and reading means for reading out the one data or the copy data in accordance with a detection result of the detecting means. It is characterized by that.

The on- vehicle data storage device according to the present invention is characterized in that the first writing means writes the one data and the copy data in different data erasure permission blocks.

A data storage method according to the present invention is a data storage method for storing data in a nonvolatile memory having a plurality of storage blocks mounted on a vehicle and from which data is erased collectively. reading a first writing step of performing a process of writing, when the first storage block by writing data by the first writing step has been filled with data, one or more data from said first storage block A plurality of storages included in the non-volatile memory, including: a data copying step for writing to another storage block; and an erasing step for erasing data in the one storage block after completion of the processing in the data copying step the block, the first writing step, and processed the data copying step and the removing step There the data erase inhibition block, until the first write step, the data copying step and see including a plurality of data erase authorization block to be processed in said erasing step, the data erasure prohibition block is filled with data The data erasure prohibiting block further includes a second writing step for performing a process of writing data to the data erasure prohibiting block, wherein the data erasure prohibiting block stores information on specifications of a vehicle to be mounted, and the first writing The setting information that can be changed by a user of the vehicle is written in the electronic step mounted on the vehicle in the insertion step, and the security-related information is written in the second writing step .

In the present invention, for a non-volatile memory such as a flash memory having a plurality of storage blocks from which data is collectively erased, one or a plurality of storage blocks among the plurality of storage blocks are handled as data erasure prohibition blocks. Data erasure processing is not performed on the data erasure prohibited block (data writing may be permitted). Therefore, data whose value is not updated can be stored in the data erasure prohibition block.
A plurality of other storage blocks are handled as data erasure permission blocks. Data is written to the data erasure enable block, and when the data erasure enable block is filled with data by writing, necessary data is read from this data erasure enable block and written to another data erasure enable block. Then, a process of updating the data erasure permission block that is a data write target is performed. After the updating process is completed, the erasing process is performed on the data erasing permission block filled with data. As a result, data can be written by sequentially using a plurality of data erasure permission blocks.
Therefore, data whose value is not updated can be stored in the data erasure prohibition block, and data whose value is updated can be stored in the data erasure permission block. Since data whose values are not updated is not saved to other storage blocks, the data is not lost. Further, since the data erasure prohibition block is not erased, the number of data rewrites does not increase, and the reliability of the data stored in this block does not decrease.

  In the present invention, data writing to the data erasure prohibiting block is permitted. When data that is not updated is stored in the data erasure prohibition block, if there is an empty area in the data erasure prohibition block, it can be used effectively. Since the data erasure prohibition block is prohibited from data erasure, data can be written until the block is filled with data. For example, data with a low value update frequency can be written.

When the data storage device is a vehicle-mounted device, the data erasure prohibition block can store, for example, information related to vehicle specifications (for example, destination) as data whose values are not updated. In addition, information such as vehicle identification information, data storage device identification information, or manufacturing date may be stored.
Further, for example, information (password or the like) related to security can be stored in the empty area of the data erasure prohibition block as data with a low update frequency.
In addition, the data erasure permission block can store in-vehicle device setting information that can be arbitrarily changed by the vehicle user.

  In the present invention, when data is written, the data is written into the data erasure permission block and the copy data of this data is written. When reading data, it is only necessary to detect errors in both written data and read data in which no error has occurred. Thereby, the reliability of the stored data can be improved. The two data may be written to different data erasure permission blocks. As a result, even if a malfunction occurs in units of blocks, data corruption can be prevented.

  According to the present invention, by providing a data erasure prohibition block in the nonvolatile memory, data that is not updated or that is updated less frequently can be stored in the nonvolatile memory. Etc. can be prevented.

It is a block diagram which shows the structure of the data storage device which concerns on this Embodiment. It is a schematic diagram for demonstrating the utilization method of the data storage area of the flash memory by a data storage device. It is a schematic diagram for demonstrating the utilization method of the data storage area of the flash memory by a data storage device. It is a schematic diagram for demonstrating the utilization method of the data storage area of the flash memory by a data storage device. It is a flowchart which shows the procedure of the data read-out process which the data storage device concerning this Embodiment performs. It is a flowchart which shows the procedure of the data writing process which the data storage device which concerns on this Embodiment performs. It is a flowchart which shows the procedure of the block update process which the data storage device which concerns on this Embodiment performs. 10 is a flowchart showing a procedure of data writing processing performed by a data storage device according to Modification 1; 10 is a schematic diagram for explaining a data writing process performed by a data storage device according to Modification 2. FIG. 10 is a flowchart showing a procedure of data read processing performed by a data storage device according to Modification 2.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a block diagram showing the configuration of the data storage device according to the present embodiment. Data storage device 1 according to the present embodiment is mounted on vehicle 100 and stores various data related to vehicle 100. The data storage device 1 is a device that can be provided as, for example, a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), or a microcomputer (microcomputer), for example, an ECU (Electronic Control Unit) mounted on the vehicle 100, for example. Responsible for arithmetic processing and storage processing.

  The data storage device 1 includes a processing unit 10, a RAM (Random Access Memory) 11, a flash memory 20, and the like. The processing unit 10 performs various arithmetic processing and control processing by reading and executing a program stored in advance in the flash memory 20. The RAM 11 is configured by using a memory element such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory), and temporarily stores various data generated in a processing process such as arithmetic processing performed by the processing unit 10. To do.

  The flash memory 20 is a non-volatile memory element and can erase data for each storage block having a predetermined size. The flash memory 20 includes a memory management unit 21 and a storage unit 30. The memory management unit 21 operates various analog circuits such as a charge pump and a sense amplifier provided in the flash memory 20 in response to a data read request, a write request, an erase request, and the like given from the processing unit 10. As a result, data is read from, written to, and erased from the storage unit 30.

  The storage unit 30 has a storage capacity of several megabytes to several hundreds of megabytes or more, and can store data even when power supply is cut off. The flash memory 20 can write data to the storage unit 30 in units of 8 bits or 16 bits by address designation, but erases data in units of storage blocks of about several kilobytes to several tens of kilobytes. There is a need. The data storage device 1 according to the present embodiment is a program storage that stores in advance a program executed by the processing unit 10 in a predetermined plurality of storage blocks among a plurality of storage blocks included in the storage unit 30 of the flash memory 20. Used as region 31.

  The program storage area 31 is treated as a data read-only storage area, except in a special case where a program is written before the factory shipment of the data storage device 1 or an ECU or the like equipped with the data storage apparatus 1. The processing unit 10 performs read processing on the program storage area 31 but does not perform write and erase processing. Alternatively, the memory management unit 21 of the flash memory 20 may receive only a data read request without receiving a data write request and an erase request for the program storage area 31 from the processing unit 10. Thereby, it is possible to prevent a program stored in advance in the program storage area 31 from being destroyed.

  Further, the data storage device 1 uses the remaining plurality of storage blocks of the storage unit 30 as a data storage area 32 for storing various data used by the processing unit 10 for arithmetic processing and the like. Furthermore, the data storage device 1 according to the present embodiment sets one or a plurality of storage blocks (one in the present embodiment) among the plurality of storage blocks included in the data storage area 32 as erasure prohibition blocks, The remaining plurality of storage blocks are set as erase permission blocks.

  The erasure prohibition block is a block that is prohibited from being an object of erasure processing, and data can be read out. Data writing to the erase prohibition block may be prohibited or may be permitted. In the present embodiment, it is assumed that data writing to the erase prohibition block is permitted. The processing unit 10 performs data read and write processing on the erase-inhibited block of the flash memory 20, but does not perform erase processing. Alternatively, the memory management unit 21 of the flash memory 20 may accept only the reading and writing of data without accepting an erase request for the erase-inhibited block from the processing unit 10. Thereby, it is possible to prevent the data stored in the erase prohibition block from being rewritten. Further, since data can be written until the erase prohibition block is filled with data, the erase prohibition block can be used effectively.

  The erasure permission block is a storage block capable of reading, writing and erasing data. In the present embodiment, it is assumed that the flash memory 20 is provided with N erase permission blocks, which are referred to as a first erase permission block, a second erase permission block,..., An Nth erase permission block. The processing unit 10 of the data storage device 1 sequentially switches the storage blocks to which data is to be written, such as first erasure permission block → second erasure permission block →... → Nth erasure permission block → first erasure permission block. While writing the data. For example, the processing unit 10 writes data to the first erasure permission block, and when the first erasure permission block is filled with data and further writing becomes impossible, the data write destination is changed. Switch to the second erase permission block. At this time, the processing unit 10 performs a block update process of reading valid data out of the data stored in the first erasure-permitted block and copying it to the second erasure-permitted block. Start writing new data. Further, the processing unit 10 performs the erasure process of the first erasure permission block after the block update process is completed. By adopting a configuration in which data is written by circulating through a plurality of erase-permitted blocks in this way, the number of data rewrites of each erase-permitted block can be averaged.

  In order to realize such data writing, the processing unit 10 stores information (management information) for determining which data is valid, for example, at a predetermined location such as the beginning or end of the erasure permission block. Or, it is written and managed in the header of each data. For example, when the data storage device 1 is configured to store the setting value of the electronic device mounted on the vehicle 100 in the flash memory 20, the processing unit 10 reads the setting value from the flash memory 20 and gives the setting value to the electronic device. When the setting is changed, the updated setting value is written in the flash memory 20. At this time, the processing unit 10 invalidates the previous set value already written in the erase-permitted block of the flash memory 20 and writes the updated set value in the empty area of the erase block. When there is no empty area in the erasure permission block, the processing unit 10 performs block update processing for copying valid data to the next erasure permission block based on the management information, and then writes the data in the new erasure permission block. . Note that the process of invalidating the previous data is not necessarily performed, and the processing unit 10 may determine which is the latest data based on, for example, the storage location (address) of the data.

  2 to 4 are schematic diagrams for explaining a method of using the data storage area 32 of the flash memory 20 by the data storage device 1. In this figure, it is assumed that the data storage area 32 of the flash memory 20 has a configuration capable of storing 16 pieces of data in each of the erase-inhibited block and each of the erase-permitted blocks, and each block is arranged in a 4 × 4 matrix. It is shown by.

  For example, as shown in FIG. 2, in the initial state such as when the vehicle 100 or the data storage device 1 is shipped from the factory, two data A and B are stored in the erase prohibition block of the flash memory 20, and the remaining data This is a free area. Since the erasure prohibition block is not subjected to data erasure processing, the data A and B stored in the erasure prohibition block are stored even when the data write processing is repeated as shown in FIGS. There is no change.

  In this example, the processing unit 10 of the data storage device 1 stores three setting values a, b, and c for the electronic device mounted on the vehicle 100 in the flash memory 20. As shown in FIG. 2, in the initial state, set values a_1, b_1, and c_1 are stored in the first erase permission block of the flash memory 20, and no data is stored in the other erase permission blocks. Thereafter, for example, when the set value b is changed, the processing unit 10 writes the new set value b_2 in the first erasure permission block and invalidates the already written set value b_1. The processing unit 10 writes a new set value every time the set values a, b, and c are changed. In this way, for example, when the setting values a_2, b_3, c_2, c_3, b_4, a_3, b_5, b_6 are written to the first erasure permission block, three of the setting values c_3, a_3, b_6 are effective setting values. (Indicated with hatching in the figure), and other setting values are invalid setting values.

  For example, as shown in FIG. 3, when the setting values c_4, b_7, a_4, and b_8 are further written to the first erasure permission block, the setting values c_4, a_4, and b_8 become valid, and the first erasure permission block stores the data In other words, no more data can be written. In this state, for example, when the set value a is changed and a new set value a_5 is written, the processing unit 10 performs an update process of an erasure permission block for writing data. In the update process, the processing unit 10 reads valid data from the first erasure permission block and copies it to the second erasure permission block. In the example shown in FIG. 3, the valid data of the first erasure permission block is the set values c_4, a_4, and b_8. However, since the new set value a_5 is written for the set value a, the processing unit 10 After copying c_4 and b_8 to the second erasure permission block, a new set value a_5 is written to the second erasure permission block.

  After completing the block update process and writing the new set value a_5, as shown in FIG. 4, the processing unit 10 performs a process of erasing the data in the first erasure permission block. Thereafter, the processing unit 10 writes a new setting value to the second erasure permission block every time the setting value is changed until the second erasure permission block is filled with data. The processing unit 10 switches the erase-permitted block for writing data in the order of the second erase-permitted block, the third erase-permitted block,..., The Nth erase-permitted block, and the first erase-permitted block.

  It should be noted that the erasure prohibition block does not need to be updated in subsequent processing, such as the manufacturing number or date of manufacture of the data storage device 1, the specification information (destination, grade, etc.) or identification information of the vehicle 100. Information can be stored in advance in the manufacturing process of the data storage device 1 or the vehicle 100. The erasure prohibition block is a storage block in which erasure of data is prohibited and the stored data is not rewritten, so that no data loss or the like occurs. In addition, in the erasure permission block, for example, with respect to an electronic device mounted on the vehicle 100, data with a high update frequency such as a setting value that can be arbitrarily changed by the user of the vehicle 100 can be stored.

  In the present embodiment, the configuration information or identification information of the vehicle 100 is stored in the erasure prohibition block, and the setting value of the electronic device is stored in the erasure permission block. However, the information stored in each block is an example. And it is not limited to this. The information stored in each block can be determined as appropriate. Information that is not updated may be stored in the erasure prohibition block, and updated information may be stored in the erasure permission block.

  FIG. 5 is a flowchart showing a procedure of data read processing performed by the data storage device 1 according to the present embodiment. The processing unit 10 of the data storage device 1 performs a storage block determination process for determining whether the data to be read is stored in an erasure prohibition block or an erasure permission block (step S1). For example, the data storage device 1 stores correspondence information between data types and storage destination blocks in advance, and determines which block stores data to be read based on the correspondence information. can do. From the result of the storage block determination process, the processing unit 10 determines whether or not the storage destination of the data to be read is an erasure prohibited block (step S2). When the data storage destination is the erase prohibition block (S2: YES), the processing unit 10 reads the data from the erase prohibition block of the flash memory 20 (step S3), and ends the data reading process.

  When the data storage destination is not an erasure prohibition block but an erasure permission block (S2: NO), the processing unit 10 selects an erasure permission block which is a target of data writing at this time (step S4). For example, when the data storage device 1 is started after the power is turned on, the processing unit 10 determines whether or not data is stored in each erasure permission block, management information of the erasure permission block in which the data is stored, and the like. With reference to this, it is determined which of the erasure permission blocks to be written is stored in the RAM 11. When the erasure permission block to be written is switched by the block update process, the processing unit 10 updates the information related to the erasure permission block to be written stored in the RAM 11. In step S <b> 4, the processing unit 10 can select an erasure permission block to be written by referring to information stored in the RAM 11.

  Next, the processing unit 10 reads the management information stored in the selected erasure permission block (step S5). The processing unit 10 reads valid data from the erase permission block selected in step S4 based on the management information read in step S5 (step S6), and ends the data reading process.

  FIG. 6 is a flowchart showing a procedure of data writing processing performed by the data storage device 1 according to the present embodiment. The processing unit 10 of the data storage device 1 selects an erasure permission block that is a target of data writing at this time (step S11). The processing unit 10 determines whether or not data can be written to the erase-permitted block depending on whether or not the selected erase-permitted block is filled with data (step S12). If data writing is not possible (S12: NO), the processing unit 10 performs a block update process for updating the write target from this erase-permitted block to the next erase-permitted block (step S13). After completion of the block update process, the processing unit 10 writes data in a new erasure permission block (step S14), and ends the data write process.

  When the data can be written (S12: YES), the processing unit 10 writes the data in the empty area of the erasure permission block selected in step S11 (step S15), and ends the data writing process. To do.

  FIG. 7 is a flowchart showing the procedure of the block update process performed by the data storage device 1 according to this embodiment, and is the process performed in step S13 of the flowchart shown in FIG. In the block update process, the processing unit 10 of the data storage device 1 extracts valid data based on the management information from the erasure permission block to which data is to be written (step S21), and uses the extracted data as the next erasure permission block. Copy (step S22). Next, the processing unit 10 switches the erase-permitted block to which data is to be written to the next erase-permitted block (step S23). Further, the processing unit 10 performs a process of erasing the data of the previous erasure permission block (step S24), and ends the block update process.

  The data storage device 1 according to the present embodiment having the above configuration treats one or a plurality of storage blocks among the plurality of storage blocks as an erasure prohibition block for the flash memory 20 having a plurality of storage blocks from which data is collectively erased. . The processing unit 10 of the data storage device 1 does not perform data erasure processing on the erasure prohibited block. In addition, the data storage device 1 treats a plurality of other storage blocks as erasure permission blocks. The processing unit 10 writes data to the erase-permitted block, and when the erase-permitted block is filled with data by writing, the valid data is read from the erase-permitted block and copied to the next erase-permitted block, A block update process for switching the storage block to be written to the next is performed. After completing the update process, the processing unit 10 performs an erasure process on the erasure permission block filled with data. As a result, the processing unit 10 writes data by sequentially using a plurality of erase permission blocks.

  Therefore, the data storage device 1 can store data whose values are not updated in the erasure prohibition block, and can store data whose values are updated in the erasure permission block. Since data whose value is not updated is not saved in another storage block, data is not lost due to a write failure. Further, since the erasure prohibition block is not subjected to data erasure processing, the number of data rewrites does not increase, and the reliability of the data stored in the storage block does not decrease.

  Note that the data storage device 1 according to the present embodiment is mounted on the vehicle 100, but is not limited thereto, and the same configuration of other various data storage devices can be applied. it can. The data storage device 1 is configured to store data in the flash memory 20, but is not limited thereto, and may be configured to store data in another nonvolatile memory that erases data in units such as blocks. .

  In addition, the processing unit 10 performs a process of sequentially switching a plurality of erasure-permitted blocks and writing data. However, the present invention is not limited to this, and the memory management unit 21 of the flash memory 20 may perform the process. In addition, the processing unit 10 does not perform the erasing process on the storage block so that the erasure prohibition block is realized. However, the present invention is not limited to this. If accepted, an erase prohibition block may be implemented as a configuration for rejecting this request.

(Modification 1)
The data storage device 1 may be configured to write data to the empty area of the erasure prohibited block of the flash memory 20. For example, when an immobilizer is mounted on the vehicle 100, the security code used for the immobilizer authentication process can be written and stored in the empty area of the erasure prohibition block of the flash memory 20. The security code of the immobilizer may be changed when, for example, the key is exchanged, but is information that is updated less frequently than the setting value of the in-vehicle device stored in the erasure permission block. Since the data storage device 1 according to the modification 1 is configured to perform data writing to the erase prohibition block of the flash memory 20, the stored data is valid or invalid as in the erase permit block. Management information for determining whether or not is stored in the erasure prohibition block.

  When it becomes necessary to write a security code, the processing unit 10 of the data storage device 1 according to the first modification determines whether there is an empty area in the erasure prohibition block, and if there is an empty area. Write. If there is no free area, the processing unit 10 does not write a security code. When the security code cannot be written because there is no empty area in the erasure prohibition block, the processing unit 10 may notify the writing failure by, for example, displaying an error message or turning on a warning lamp. In such a case, it is possible to erase and rewrite data in the erasure prohibited block of the flash memory 20 by using a special device or performing a special operation in a dealer of the vehicle 100 or a maintenance shop, for example. It may be a configuration.

  FIG. 8 is a flowchart illustrating a procedure of data writing processing performed by the data storage device 1 according to the first modification. The processing unit 10 of the data storage device 1 according to the modification 1 determines whether or not the data to be written is a security code when writing data to the flash memory 20 (step S31). If the data to be written is not a security code (S31: NO), the processing unit 10 performs a data writing process to the erasure permission block of the flash memory 20 (step S32) and ends the process. The data writing process performed in step S32 is the same as the process shown in FIG.

  If the data to be written is a security code (S31: YES), the processing unit 10 determines whether there is an empty area in the erasure prohibition block of the flash memory 20 (step S33). If there is an empty area in the erasure prohibition block (S33: YES), the processing unit 10 writes a security code in the erasure prohibition block (step S34), and ends the data writing process. If there is no empty area in the erasure prohibition block (S33: NO), the processing unit 10 performs error processing such as display of an error message (step S35), and ends the processing without writing data.

  As described above, the data storage device 1 according to the modified example 1 can effectively use the empty area of the erasure prohibition block by permitting data writing to the erasure prohibition block of the flash memory 20. Since the erasure prohibition block is prohibited from performing data erasure processing, data can be written until the block is filled with data. For example, data with a low update frequency such as a security code can be written in the erasure prohibition block. Note that data to be written to the erasure prohibition block may be data other than the security code.

(Modification 2)
When the data storage device 1 according to the modification 2 performs data writing, the data storage device 1 performs two data writing operations, ie, primary data and sub data (data obtained by copying the primary data). FIG. 9 is a schematic diagram for explaining a data writing process performed by the data storage device 1 according to the second modification. The data storage device 1 according to the modification 2 uses two blocks as one set for a plurality of erasure permission blocks of the flash memory 20. For example, the first erase permission block and the second erase permission block are set as one set, the third erase permission block and the fourth erase permission block are set as one set,..., The N-1th erase permission block and the Nth erase permission block are 1 A pair (where N is an even number). For example, the data storage device 1 writes the set value a_1 as positive data in the first erasure permission block and then writes the same setting value a_1 as sub data in the second erasure permission block. As a result, the same data is written in the two erase-permitted blocks made into one set.

  Further, the data storage device 1 according to the modification 2 has an error detection function for determining whether or not there is an error in the data stored in the flash memory 20. When reading data from the erasure permission block, the data storage device 1 first determines whether or not there is an error in the positive data stored in one erasure permission block, and if there is no error, reads the positive data. If it is determined that there is an error in the primary data stored in one erase-permitted block, the data storage device 1 reads the sub data stored in the other erase-permitted block. Note that it may be determined whether there is an error in the sub data.

  FIG. 10 is a flowchart showing a procedure of data read processing performed by the data storage device 1 according to the second modification. The processing unit 10 of the data storage device 1 according to the modification 2 performs a storage block determination process that determines whether the data to be read is stored in an erasure prohibition block or an erasure permission block (step S41). Based on the result of the storage block determination process, the processing unit 10 determines whether or not the storage destination of the data to be read is an erasure prohibition block (step S42). When the data storage destination is the erasure prohibition block (S42: YES), the processing unit 10 reads the data from the erasure prohibition block of the flash memory 20 (step S43), and ends the process.

  When the data storage destination is not an erasure prohibition block but an erasure permission block (S42: NO), the processing unit 10 selects two erasure permission blocks that are data write targets (step S44). The processing unit 10 reads the management information of the selected erase-permitted block (step S45), and reads valid data from one erase-permitted block (step S46). The processing unit 10 determines whether or not there is an error in the data read from one erasure permission block (step S47). If there is no error (S47: NO), the processing is ended with this data as read data. To do. If there is an error in the data read from one erasure-permitted block (S47: YES), the processing unit 10 reads valid data from the other erasure-permitted block (step S48), and ends the process using this data as read data. To do.

  As described above, the data storage device 1 according to the modification 2 writes the primary data and the sub data to the erasure permission block when writing the data. In the case of reading data, the data storage device 1 performs error detection of the primary data and the secondary data stored in the erasure permission block, and reads any data according to the result. Thereby, the reliability of the data stored in the erasure permission block can be improved. The data storage device 1 may be configured to store the primary data and the sub data in the same erasure permission block, instead of storing the primary data and the sub data in different erasure permission blocks.

1 Data Storage Device 10 Processing Unit 11 RAM
DESCRIPTION OF SYMBOLS 20 Flash memory 21 Memory management part 30 Storage part 31 Program storage area 32 Data storage area 100 Vehicle

Claims (4)

In a vehicle-mounted data storage device including a nonvolatile memory that is mounted on a vehicle and has a plurality of storage blocks from which data is erased collectively,
First writing means for performing processing of writing data to the storage block;
A data copying means for writing into other memory blocks are read when the first storage block is filled with data by writing the data, one or more data from said first storage block according to said first writing means,
Erasing means for performing processing for erasing the data in the one storage block after the processing by the data copying means is completed,
In the plurality of storage blocks included in the nonvolatile memory,
A data erasure prohibition block not subject to processing by the first writing means, the data copying means and the erasing means;
It said first writing means, seen including a plurality of data erase authorization block to be processed of the data copying means and said erasing means,
A second writing means for performing a process of writing data to the data erasure prohibition block until the data erasure prohibition block is filled with data;
In the data erasure prohibition block, information related to the specifications of the vehicle to be mounted is stored,
The first writing unit writes setting information that can be changed by a user of the vehicle with respect to an electronic device mounted on the vehicle.
The in-vehicle data storage device, wherein the second writing means writes information related to security .   The first writing means writes the one data and copy data of the one data when writing one data to the data erasure permission block,
Detecting means for detecting an error in data written in the nonvolatile memory;
Reading means for reading out the one data or the copy data according to a detection result of the detecting means;
Having
The in-vehicle data storage device according to claim 1. The first writing means writes the one data and the copy data in different data erasure permission blocks.
The in-vehicle data storage device according to claim 2. In a data storage method for storing data in a non-volatile memory mounted on a vehicle and having a plurality of storage blocks from which data is erased collectively,
A first writing step for performing a process of writing data to the storage block;
If the first storage block is filled with data by writing the data according to the first writing step, a data copying step of writing the reading one or more data from the first storage block to the other memory blocks,
An erasing step for erasing data of the one storage block after the processing by the data copying step is completed,
In the plurality of storage blocks included in the nonvolatile memory,
A data erasure prohibition block not to be processed in the first writing step, the data copying step, and the erasing step;
The first writing step, seen including a plurality of data erase authorization block to be processed of the data copying step and the removing step,
A second writing step of performing a process of writing data to the data erasure prohibition block until the data erasure prohibition block is filled with data;
In the data erasure prohibition block, information related to the specifications of the vehicle to be mounted is stored,
In the first writing step, setting information that can be changed by a user of the vehicle is written regarding the electronic device mounted on the vehicle.
A data storage method, wherein information relating to security is written in the second writing step .

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