JP2019204229A - Electronic apparatus and memory management system and program - Google Patents

Abstract

To provide an electronic apparatus capable of realizing long-term data retention while suppressing reduction in a life time of data rewriting of a nonvolatile memory.SOLUTION: An electronic apparatus 1 determines execution propriety of refreshing of a nonvolatile memory 2 based on a refresh execution interval Dx corresponding to a data rewriting execution frequency N of the nonvolatile memory 2 in a temperature range including a mean air temperature Ta at a region corresponding to location information P and a lapse time from the previous refresh execution date Da of the nonvolatile memory 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device having a nonvolatile memory.

  In general, the data retention characteristics (hereinafter referred to as retention characteristics) of a nonvolatile memory greatly vary depending on the use temperature or storage temperature. For example, when the nonvolatile memory is placed in a high temperature environment, the retention characteristics are degraded. In order to retain data in the nonvolatile memory for a long period of time, for example, in the electronic device described in Patent Document 1, the nonvolatile memory is nonvolatile each time the time when the nonvolatile memory is placed in a high temperature environment equal to or higher than a predetermined temperature exceeds a threshold value. Refreshing the memory. The refresh is a process of rewriting data held in the nonvolatile memory.

JP 2010-27021 A

The electronic device described in Patent Literature 1 periodically acquires temperature information of the electronic device in operation using a temperature sensor, and measures the time when the acquired temperature exceeds a certain temperature.
In general, when the electronic device is an in-vehicle device such as a car navigation device, the time during which the in-vehicle device is operating is about several hours during which the vehicle is used in one day, and the other time is in operation. Often not.
Furthermore, the retention characteristics of the non-volatile memory are not reduced only when the temperature at which the non-volatile memory is placed exceeds a certain temperature, but the average of the retention of the non-volatile memory regardless of the operation of the electronic device. Fluctuates depending on the temperature.
For this reason, in the electronic device described in Patent Document 1, the influence of the change in the temperature environment on the retention characteristics cannot be appropriately reflected in the refresh execution interval, and the refresh is executed more times than necessary and is nonvolatile. The data rewrite life of the memory may be reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and to obtain an electronic device that can realize long-term data retention while suppressing a decrease in the data rewrite life of a nonvolatile memory.

  An electronic device according to the present invention is an electronic device having a nonvolatile memory, and includes a position information acquisition unit, a refresh interval acquisition unit, a determination unit, and a refresh execution unit. The position information acquisition unit acquires position information of the electronic device. The refresh interval acquisition unit includes the average temperature in the region corresponding to the location information acquired by the location information acquisition unit from the refresh execution interval corresponding to the range of the number of times data is rewritten in the nonvolatile memory in a plurality of temperature ranges. The refresh execution interval corresponding to the number of data rewrite executions of the nonvolatile memory in the temperature range to be acquired is acquired. The determination unit determines whether or not the nonvolatile memory can be refreshed based on the refresh execution interval acquired by the refresh interval acquisition unit and the elapsed time from the previous refresh execution of the nonvolatile memory. The refresh execution unit executes refresh of the nonvolatile memory when the determination unit determines that the refresh can be performed.

  According to the present invention, the electronic device performs the refresh execution interval corresponding to the data rewrite execution count of the nonvolatile memory in the temperature range including the average temperature in the region corresponding to the position information of the electronic device, and the previous refresh of the nonvolatile memory. Based on the elapsed time from the execution, it is determined whether or not the nonvolatile memory can be refreshed. As a result, an appropriate refresh execution interval corresponding to the temperature environment in which the nonvolatile memory is placed and the number of data rewrites is acquired. Thus, the electronic device can suppress the deterioration of the data rewrite life of the nonvolatile memory and Data retention for a period can be realized.

It is a block diagram which shows the structure of the electronic device which concerns on Embodiment 1 of this invention. 3 is a diagram showing an example of a first DB constituting a refresh execution interval database (hereinafter referred to as DB) in Embodiment 1. FIG. 6 is a diagram illustrating an example of a second DB constituting the refresh execution interval DB in the first embodiment. FIG. 3 is a flowchart showing an operation of the electronic device according to the first embodiment. It is a graph which shows the relationship between the data rewrite frequency of flash memory, and retention time with respect to temperature. FIG. 6A is a block diagram illustrating a hardware configuration for realizing the functions of the electronic device according to the first embodiment. FIG. 6B is a block diagram illustrating a hardware configuration that executes software that implements the functions of the electronic apparatus according to the first embodiment. 1 is a block diagram illustrating a configuration of a memory management system according to a first embodiment. It is a block diagram which shows the structure of the electronic device which concerns on Embodiment 2 of this invention. 10 is a flowchart illustrating an operation of the electronic device according to the second embodiment. It is a block diagram which shows the structure of the electronic device which concerns on Embodiment 3 of this invention. FIG. 20 is a diagram illustrating an example of a second DB constituting the refresh execution interval DB in the third embodiment. 14 is a flowchart illustrating an operation of the electronic device according to the third embodiment.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of an electronic apparatus 1 according to Embodiment 1 of the present invention.
The electronic device 1 includes a non-volatile memory 2 and may be an in-vehicle device mounted on a vehicle such as a car navigation device. The nonvolatile memory 2 is, for example, a flash memory mounted on the electronic device 1 and is realized by a solid state drive (SSD), an embedded multimedia card (eMMC), or an SD (secure digital) card.

  The electronic device 1 includes a position information acquisition unit 10, a refresh interval acquisition unit 11, a determination unit 12, and a refresh execution unit 13. The position information acquisition unit 10 acquires position information P of the electronic device 1. The position information P may be, for example, the latitude and longitude of the position of the electronic device 1.

  The refresh interval acquisition unit 11 is a refresh execution interval corresponding to the data rewrite execution count N of the nonvolatile memory 2 in a temperature range including the average temperature Ta of the region corresponding to the location information P acquired by the location information acquisition unit 10. Dx is acquired from the refresh execution interval DB 20. The refresh execution interval DB 20 is a database in which the average temperature Ta of the region corresponding to the position information P and the refresh execution interval Dx corresponding to the range of the data rewrite execution count N of the nonvolatile memory 2 in a plurality of temperature ranges are registered. It is.

  The determination unit 12 determines whether or not the nonvolatile memory 2 can be refreshed based on the refresh execution interval Dx acquired by the refresh interval acquisition unit 11 and the elapsed time from the previous refresh execution date and time Da to the current date and time Db. . For example, if the time obtained by subtracting Db from Da is longer than Dx, the determination unit 12 determines that the nonvolatile memory 2 can be refreshed. If the time obtained by subtracting Db from Da is equal to or less than Dx, the determination unit 12 determines that the nonvolatile memory 2 cannot be refreshed.

  The refresh execution unit 13 performs the refresh of the nonvolatile memory 2 when the determination unit 12 determines that the refresh can be performed. For example, the refresh execution unit 13 reads data from the nonvolatile memory 2, preferentially selects a storage area with a small total number of data rewrites in the nonvolatile memory 2, and rewrites the read data. When the refresh is executed, the refresh execution unit 13 updates the data rewrite execution count N and the previous refresh execution date / time Da.

  The nonvolatile memory 2 stores a refresh execution interval DB 20, a data rewrite execution count N, a previous refresh execution date / time Da, and saved data. The stored data is, for example, data to be refreshed. The value of the data rewrite execution count N is not limited to refresh, and is updated each time data rewrite of the nonvolatile memory 2 is executed. The data rewrite execution count N and the previous refresh execution date / time Da may be stored in a specific register of the nonvolatile memory 2.

  FIG. 2 is a diagram illustrating an example of the first DB 20a constituting the refresh execution interval DB 20. FIG. 3 is a diagram illustrating an example of the second DB 20b configuring the refresh execution interval DB 20. The refresh execution interval DB 20 includes a first DB 20a and a second DB 20b. In the first DB 20a, an area and an average temperature Ta in the area are registered. In addition, a refresh execution interval Dx corresponding to the number N of data rewrite executions of the nonvolatile memory 2 in a plurality of temperature ranges is registered in the second DB 20b.

The refresh execution interval Dx is an appropriate refresh execution interval that suppresses a decrease in the data rewrite life of the nonvolatile memory 2 and is determined in advance according to a plurality of temperature ranges and the number of data rewrite executions N. . The temperature range is a temperature range of the average temperature Ta.
In addition, although the refresh execution interval DB20 composed of the first DB 20a and the second DB 20b is shown, the contents of both the first DB 20a and the second DB 20b are registered as one in the refresh execution interval DB20. DB may be sufficient.

Next, the operation will be described.
FIG. 4 is a flowchart showing the operation of the electronic apparatus 1 and shows a series of processes for determining whether or not the nonvolatile memory 2 can be refreshed.
When the system is activated, the position information acquisition unit 10 acquires the position information P of the electronic device 1 (step ST1). The position information P acquired by the position information acquisition unit 10 is output to the refresh interval acquisition unit 11. Next, the refresh interval acquisition unit 11 acquires the data rewrite execution count N from the nonvolatile memory 2 (step ST2), and acquires the previous refresh execution date Da from the nonvolatile memory 2 (step ST3).

  The determination unit 12 acquires the current date and time Db (step ST4). As a method for obtaining the current date and time Db, for example, an internal clock of the electronic device 1 may be used, or time information included in a GNSS signal received from a GNSS (Global Positioning Satellite System) satellite may be used.

  Next, the refresh interval acquisition unit 11 acquires the average temperature Ta in the region corresponding to the position information P acquired by the position information acquisition unit 10 from the first DB 20a of the refresh execution interval DB 20 (step ST5). For example, when the position indicated by the position information P is included in the area A, the refresh interval acquisition unit 11 acquires 15 ° C. as the average temperature Ta from the first DB 20a illustrated in FIG.

Subsequently, the refresh interval acquisition unit 11 acquires, from the second DB 20b of the refresh execution interval DB 20, the refresh execution interval Dx corresponding to the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the average temperature Ta. (Step ST6).
For example, when the average temperature Ta acquired from the first DB 20a is 15 ° C. and the data rewrite execution count N acquired from the nonvolatile memory 2 is 3500, the refresh interval acquisition unit 11 is shown in FIG. The refresh execution interval Dx (5 years) is acquired from the second DB 20b. The refresh execution interval Dx acquired by the refresh interval acquisition unit 11 is output to the determination unit 12.

  The determination unit 12 checks whether or not the time (Db−Da) elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST7). Here, when the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is equal to or shorter than the refresh execution interval Dx (step ST7; NO), the determination unit 12 executes the refresh of the nonvolatile memory 2 The process of FIG. 4 is complete | finished by determining with improper.

  On the other hand, when the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST7; YES), the determination unit 12 can execute the refresh of the nonvolatile memory 2. And the refresh result is notified to the refresh execution unit 13. Upon receiving the notification, the refresh execution unit 13 performs the refresh of the nonvolatile memory 2 (step ST8).

When the refresh execution unit 13 completes the refresh of the nonvolatile memory 2, it updates the previous refresh execution date / time Da with the current date / time Db (step ST9). Further, the refresh execution unit 13 updates the data rewrite execution count N of the storage area to which data has been rewritten by the refresh process. Thereafter, the process of FIG. 4 is terminated.
Note that the series of processes in the flowchart of FIG. 4 shows an example of a process for determining whether or not the nonvolatile memory 2 can be refreshed, and the order of acquiring various types of information may be changed.

FIG. 5 is a graph showing the relationship between the number of times data is rewritten in the flash memory and the retention time with respect to temperature. As shown in FIG. 5, the retention characteristic of the flash memory does not decrease when the temperature at which the flash memory is placed exceeds a certain temperature, but varies according to the temperature. For this reason, in the electronic device described in Patent Document 1, the influence of changes in the temperature environment on the retention characteristics cannot be appropriately reflected in the refresh execution interval.
On the other hand, in the electronic device 1 according to the first embodiment, since the optimum refresh execution interval Dx according to the average temperature Ta and the data rewrite execution count N in the area where the electronic device 1 exists is acquired, it is non-volatile. The data can be retained for a long time without reducing the data rewriting life of the volatile memory 2.

  The functions of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 in the electronic device 1 are realized by a processing circuit. That is, the electronic device 1 includes a processing circuit for executing the processing from step ST1 to step ST9 in FIG. This processing circuit may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory.

  FIG. 6A is a block diagram illustrating a hardware configuration that implements the functions of the electronic device 1. FIG. 6B is a block diagram illustrating a hardware configuration that executes software that implements the functions of the electronic device 1. 6A and 6B, the GNSS receiver 100 receives a GNSS signal from a GNSS satellite. The position information acquisition unit 10 acquires the position information P of the electronic device 1 from the GNSS signal received by the GNSS receiver 100. Further, the determination unit 12 may acquire the current date and time Db using time information included in the GNSS signal. The non-volatile memory 101 is the non-volatile memory 2 shown in FIG.

  When the processing circuit is the dedicated hardware processing circuit 102 shown in FIG. 6A, the processing circuit 102 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, or an ASIC (Application Specific Integrated Circuit). ), FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 in the electronic device 1 may be realized by separate processing circuits, and these functions are combined into one processing circuit. It may be realized.

  When the processing circuit is the processor 103 shown in FIG. 6B, the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 in the electronic device 1 are software, firmware, or software and firmware. Realized by a combination of The software or firmware is described as a program and stored in the nonvolatile memory 101.

  The processor 103 reads out and executes the program stored in the nonvolatile memory 101, thereby realizing the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 in the electronic device 1. To do. That is, the electronic device 1 includes a nonvolatile memory 101 for storing a program that, when executed by the processor 103, results from the processing from step ST1 to step ST9 shown in FIG. These programs cause the computer to execute the procedures or methods of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13. The nonvolatile memory 101 stores a program for causing a computer to function as the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13. Note that the above program may be stored in a storage device provided separately from the nonvolatile memory 101 as long as the program can read data from the processor 103.

  The functions of the position information acquisition unit 10, the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 may be partially realized by dedicated hardware and partially realized by software or firmware. For example, the position information acquisition unit 10 realizes the function with a processing circuit that is dedicated hardware, and the refresh interval acquisition unit 11, the determination unit 12, and the refresh execution unit 13 have the processor 103 stored in the nonvolatile memory 101. Functions are realized by reading and executing programs. As described above, the processing circuit can realize the above functions by hardware, software, firmware, or a combination thereof.

Although the case where the refresh execution interval DB 20, the data rewrite execution count N, and the previous refresh execution date / time Da are stored in the nonvolatile memory 2 is shown, the first embodiment is not limited to this. For example, these pieces of information may be stored by an external server device.
FIG. 7 is a block diagram showing a configuration of the memory management system 3 according to the first embodiment.
In the memory management system 3, the electronic device 1 having the nonvolatile memory 2 can be connected to the server device 5 via the network 4. The refresh execution interval DB 20 for the nonvolatile memory 2, the data rewrite execution count N of the nonvolatile memory 2, and the previous refresh execution date / time Da are stored in the server device 5.

  The refresh interval acquisition unit 11 included in the electronic device 1 acquires the refresh execution interval Dx and the data rewrite execution count N from the server device 5 via the network 4. The determination unit 12 also acquires the previous refresh execution date / time Da from the server device 5 via the network 4. When refreshing the nonvolatile memory 2, the refresh execution unit 13 updates the data rewrite execution count N and the previous refresh execution date / time Da stored in the server device 5 via the network 4. As a result, the electronic device 1 provided in the memory management system 3 can realize long-term data retention while suppressing a decrease in the data rewriting life of the nonvolatile memory 2.

  Note that the server apparatus 5 may store at least one of the refresh execution interval DB 20, the data rewrite execution count N, and the previous refresh execution date / time Da, as long as the apparatus can read data from the electronic device 1. This information may be stored by a separate device.

As described above, the electronic apparatus 1 according to the first embodiment has the refresh execution interval corresponding to the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the average temperature Ta of the area corresponding to the position information P. Whether or not the nonvolatile memory 2 can be refreshed is determined based on Dx and the time elapsed since the previous refresh execution date and time Da. As a result, an appropriate refresh execution interval Dx corresponding to the temperature environment in which the nonvolatile memory 2 is placed and the number N of data rewrites is acquired, and the electronic device 1 reduces the data rewrite life of the nonvolatile memory 2. Long-term data retention can be realized while suppressing.
In particular, since the average temperature Ta in the area where the electronic device 1 is placed is used, even if the electronic device 1 is an in-vehicle device, the storage temperature of the nonvolatile memory 2 can be estimated regardless of the operation of the electronic device 1. The estimated temperature can be reflected in the determination of the refresh execution interval Dx.

Embodiment 2. FIG.
FIG. 8 is a block diagram showing a configuration of an electronic apparatus 1A according to Embodiment 2 of the present invention. In FIG. 8, the same components as those of FIG. The electronic device 1 </ b> A includes a nonvolatile memory 2 and may be an in-vehicle device mounted on a vehicle such as a car navigation device. As shown in FIG. 8, the electronic device 1 </ b> A includes a position information acquisition unit 10, a refresh interval acquisition unit 11 </ b> A, a determination unit 12, a refresh execution unit 13, and a storage temperature calculation unit 14.

When the electronic device 1A moves and the area is changed from the previous refresh execution date Da for the nonvolatile memory 2, the average temperature Ta of the area where the electronic device 1A is placed may also change. This is a situation that can occur sufficiently when the electronic device 1A is an in-vehicle device.
Therefore, in the electronic apparatus 1A according to the second embodiment, the average storage temperature Tc of the nonvolatile memory 2 from the previous refresh execution date / time Da is reflected in the determination of the refresh execution interval Dx. The average storage temperature Tc is an average storage temperature of the nonvolatile memory 2 from the previous refresh execution date Da to the current date Db with respect to the nonvolatile memory 2. By using this average storage temperature Tc, the influence of the temperature change when the electronic device 1A moves between regions is mitigated, so that the electronic device 1A suppresses a decrease in the data rewrite life of the nonvolatile memory 2. Long-term data retention can be realized.

The storage temperature calculation unit 14 calculates the average storage temperature Tc of the nonvolatile memory 2 from the previous refresh execution date Da for the nonvolatile memory 2.
The refresh interval acquisition unit 11A updates the refresh execution interval Dx corresponding to the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the average storage temperature Tc calculated by the storage temperature calculation unit 14 from the refresh execution interval DB20. To get.

  The processing circuit that realizes the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11A, the determination unit 12, the refresh execution unit 13, and the storage temperature calculation unit 14 is the processing circuit 102 that is dedicated hardware illustrated in FIG. 6A. There may be. In addition, processing circuits that realize the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11A, the determination unit 12, the refresh execution unit 13, and the storage temperature calculation unit 14 are stored in the nonvolatile memory 101 illustrated in FIG. 6B. The processor 103 that executes the program may be used. Further, part of the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11A, the determination unit 12, the refresh execution unit 13, and the storage temperature calculation unit 14 are realized by dedicated hardware, and part is realized by software or firmware. May be.

Next, the operation will be described.
FIG. 9 is a flowchart showing the operation of the electronic apparatus 1A, and shows a series of processes for determining whether or not the nonvolatile memory 2 can be refreshed.
When the system is activated, the position information acquisition unit 10 acquires the position information P of the electronic device 1A (step ST1a). The position information P acquired by the position information acquisition unit 10 is output to the storage temperature calculation unit 14. Next, the refresh interval acquisition unit 11A acquires the data rewrite execution count N from the nonvolatile memory 2 (step ST2a).

  The determination unit 12 and the storage temperature calculation unit 14 obtain the previous refresh execution date / time Da from the nonvolatile memory 2 (step ST3a), and obtain the current date / time Db from the nonvolatile memory 2 (step ST4a). As in the first embodiment, the current date and time Db may be acquired using the internal clock of the electronic apparatus 1A or using time information included in the GNSS signal received from the GNSS satellite.

  The storage temperature calculation unit 14 acquires the average temperature Ta of the area corresponding to the position information P of the electronic device 1A from the refresh execution interval DB 20 (step ST5a). Furthermore, the storage temperature calculation unit 14 acquires the average storage temperature Tb from the nonvolatile memory 2 up to the previous refresh execution date Da for the nonvolatile memory 2 (step ST6a).

The storage temperature calculation unit 14 specifies the date and time when the system was activated, that is, the previous activation date and time of the electronic device 1A, and calculates the elapsed time Dn from the previous refresh execution date and time Da to the previous activation of the electronic device 1A. . The storage temperature calculation unit 14 calculates the elapsed time Dm from the previous activation of the electronic device 1A to the present using the current date and time Db. The storage temperature calculation unit 14 uses the average temperature Ta and the average storage temperature Tb of the area corresponding to the elapsed time Dn, the elapsed time Dm, and the position information P, and the average storage temperature of the nonvolatile memory 2 according to the following formula (1). Tc is calculated (step ST7a).
Tc = (Dn × Tb + Dm × Ta) / (Dn + Dm) (1)

  The average storage temperature Tc calculated by the storage temperature calculation unit 14 is output to the refresh interval acquisition unit 11A. Moreover, the storage temperature calculation unit 14 updates the current average storage temperature Tb stored in the nonvolatile memory 2 with the calculated average storage temperature Tc.

  The refresh interval acquisition unit 11A sets the refresh execution interval Dx corresponding to the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the average storage temperature Tc calculated by the storage temperature calculation unit 14 as the refresh execution interval DB20. (Step ST8a). The refresh execution interval Dx acquired by the refresh interval acquisition unit 11A is output to the determination unit 12.

  The determination unit 12 confirms whether the time (Db−Da) elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST9a). When the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is equal to or shorter than the refresh execution interval Dx (step ST9a; NO), the determination unit 12 determines that the refresh of the nonvolatile memory 2 cannot be performed. Then, the process of FIG.

  When the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST9a; YES), the determination unit 12 determines that refresh of the nonvolatile memory 2 can be performed. Then, this determination result is notified to the refresh execution unit 13. Upon receiving the notification, the refresh execution unit 13 performs the refresh of the nonvolatile memory 2 (step ST10a).

When the refresh execution unit 13 completes the refresh of the nonvolatile memory 2, it updates the previous refresh execution date / time Da with the current date / time Db (step ST11a).
Further, the refresh execution unit 13 updates the data rewrite execution count N of the storage area to which data has been rewritten by the refresh process. Thereafter, the process of FIG. 9 is terminated.
Note that the series of processing in the flowchart of FIG. 9 shows an example of processing for determining whether or not the refresh of the nonvolatile memory 2 can be performed, and the order of acquiring various types of information may be changed.

  Note that at least one of the refresh execution interval DB 20, the average storage temperature Tb, the data rewrite execution count N, and the previous refresh execution date / time Da may be stored in a server device that can communicate with the electronic apparatus 1A. As long as the data can be read from the electronic device 1A, these pieces of information may be stored in different devices.

  As described above, the electronic device 1A according to the second embodiment has the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the average storage temperature Tc of the nonvolatile memory 2 from the previous refresh execution date / time Da. Whether or not the nonvolatile memory 2 can be refreshed is determined based on the refresh execution interval Dx corresponding to the above and the elapsed time from the previous refresh execution date and time Da. As a result, the influence of the temperature change when the electronic device 1A moves between the regions is mitigated, so that the electronic device 1A can hold data for a long time while suppressing a decrease in the data rewriting life of the nonvolatile memory 2. Can be realized.

Embodiment 3 FIG.
FIG. 10 is a block diagram showing a configuration of an electronic apparatus 1B according to Embodiment 3 of the present invention. In FIG. 10, the same components as those in FIG.
The electronic device 1B includes a nonvolatile memory 2 and may be a vehicle-mounted device mounted on a vehicle such as a car navigation device. As shown in FIG. 10, the electronic device 1 </ b> B includes a position information acquisition unit 10, a refresh interval acquisition unit 11 </ b> B, a determination unit 12, a refresh execution unit 13, a device internal temperature acquisition unit 15, an outside air temperature acquisition unit 16, and a temperature correction unit 17. It is configured with.

  The device internal temperature acquisition unit 15 acquires temperature information indicating the temperature Ti inside the electronic device 1B. For example, the in-device temperature acquisition unit 15 may acquire the temperature Ti in the device detected by a temperature sensor mounted on the electronic device 1B.

  The outside air temperature acquisition unit 16 acquires temperature information indicating the outside air temperature To outside the electronic device 1B. For example, the outside air temperature acquisition unit 16 may acquire the outside air temperature To detected by an outside air temperature clock mounted on the vehicle. Moreover, the outside air temperature acquisition part 16 is good also considering the temperature information of the area | region where the electronic device 1B acquired from the external server apparatus or the portable information terminal exists as the outside temperature To.

  The temperature correction unit 17 is a region corresponding to the position information P of the electronic device 1B based on the internal temperature Ti acquired by the internal temperature acquisition unit 15 and the external air temperature To acquired by the external air temperature acquisition unit 16. An estimated storage temperature Tx obtained by correcting the average temperature Ta is calculated. The estimated storage temperature Tx calculated by the temperature correction unit 17 is output to the refresh interval acquisition unit 11B.

  The refresh interval acquisition unit 11B acquires from the refresh execution interval DB 20 the refresh execution interval Dx corresponding to the data rewrite execution count N in the temperature range including the estimated storage temperature Tx obtained by correcting the average temperature Ta.

  FIG. 11 is a diagram illustrating an example of the second DB 20c configuring the refresh execution interval DB 20 according to the third embodiment. The refresh execution interval DB 20 is composed of the first DB 20a and the second DB 20c shown in FIG. In the first DB 20a, an area and an average temperature Ta in the area are registered.

  In the second DB 20c, refresh execution intervals Dx corresponding to the data rewrite execution count N of the nonvolatile memory 2 in a plurality of temperature ranges are registered. Here, the temperature range is a temperature range of the estimated storage temperature Tx. Note that the refresh execution interval DB 20 may be a DB in which the contents of both the first DB 20a and the second DB 20c are registered as one.

A processing circuit for realizing the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11B, the determination unit 12, the refresh execution unit 13, the in-apparatus temperature acquisition unit 15, the outside air temperature acquisition unit 16, and the temperature correction unit 17 is illustrated in FIG. The processing circuit 102 which is the dedicated hardware shown in FIG. The processing circuit for realizing the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11B, the determination unit 12, the refresh execution unit 13, the in-apparatus temperature acquisition unit 15, the outside air temperature acquisition unit 16, and the temperature correction unit 17 is illustrated in FIG. The processor 103 that executes the program stored in the nonvolatile memory 101 shown in 6B may be used.
Furthermore, some of the functions of the position information acquisition unit 10, the refresh interval acquisition unit 11B, the determination unit 12, the refresh execution unit 13, the device internal temperature acquisition unit 15, the outside air temperature acquisition unit 16, and the temperature correction unit 17 are dedicated hardware. May be realized by software or firmware.

Next, the operation will be described.
FIG. 12 is a flowchart showing the operation of the electronic apparatus 1B, and shows a series of processes for determining whether or not the nonvolatile memory 2 can be refreshed.
The device internal temperature acquisition unit 15 acquires the temperature Ti in the device immediately after the system is started (step ST1b). Subsequently, the outside air temperature acquisition unit 16 acquires the outside air temperature To (step ST2b). The position information acquisition unit 10 acquires the position information P of the electronic device 1B (step ST3b). The temperature information indicating the temperature Ti in the device, the temperature information indicating the outside air temperature To, and the position information P are output to the temperature correction unit 17.

  The refresh interval acquisition unit 11B acquires the data rewrite execution count N from the nonvolatile memory 2 (step ST4b). The determination unit 12 acquires the previous refresh execution date / time Da from the nonvolatile memory 2 (step ST5b), and acquires the current date / time Db from the nonvolatile memory 2 (step ST6b). The temperature correction unit 17 acquires the average temperature Ta of the area corresponding to the position information P of the electronic device 1B from the first DB 20a of the refresh execution interval DB 20 (step ST7b).

Next, the temperature correction unit 17 calculates the estimated storage temperature Tx of the nonvolatile memory 2 in which the average temperature Ta is corrected using the average temperature Ta, the temperature Ti inside the device, and the outside air temperature To according to the following formula (2). (Step ST8b). The estimated storage temperature Tx calculated by the temperature correction unit 17 is output to the refresh interval acquisition unit 11B.
Tx = Ta + (Ti−To) (2)

  Subsequently, the refresh interval acquisition unit 11B sets the refresh execution interval Dx corresponding to the data rewrite execution count N of the nonvolatile memory 2 in the temperature range including the estimated storage temperature Tx calculated by the temperature correction unit 17 as the refresh execution interval. Obtained from the second DB 20c of the DB 20 (step ST9b). The refresh execution interval Dx acquired by the refresh interval acquisition unit 11B is output to the determination unit 12.

  The determination unit 12 checks whether the time (Db−Da) elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST10b). When the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is equal to or shorter than the refresh execution interval Dx (step ST10b; NO), the determination unit 12 determines that the refresh of the nonvolatile memory 2 cannot be performed. Then, the process of FIG.

  On the other hand, when the length of time elapsed from the previous refresh execution date / time Da to the current date / time Db is longer than the refresh execution interval Dx (step ST10b; YES), the determination unit 12 can execute the refresh of the nonvolatile memory 2 And the refresh execution unit 13 is notified of the determination result. Upon receiving the notification, the refresh execution unit 13 performs the refresh of the nonvolatile memory 2 (step ST11b).

When the refresh execution unit 13 completes the refresh of the nonvolatile memory 2, it updates the previous refresh execution date / time Da with the current date / time Db (step ST12b).
Further, the refresh execution unit 13 updates the data rewrite execution count N of the storage area to which data has been rewritten by the refresh process. Thereafter, the process of FIG. 12 is terminated.
Note that the series of processes in the flowchart shown in FIG. 12 shows an example of a process for determining whether or not the refresh of the nonvolatile memory 2 can be performed, and the order of acquiring various types of information may be changed.

  Note that at least one of the refresh execution interval DB 20, the average storage temperature Tb, the data rewrite execution count N, and the previous refresh execution date / time Da may be stored in a server device that can communicate with the electronic device 1B. As long as the device can read data from the electronic device 1B, these pieces of information may be stored in different devices.

  The estimated storage temperature Tx is an error between the average temperature Ta in the area where the electronic device 1B is placed and the actual storage temperature of the nonvolatile memory 2 based on the difference between the temperature Ti inside the electronic device 1B and the outside air temperature To. Is corrected. Thereby, the estimated storage temperature Tx is closer to the actual storage temperature of the nonvolatile memory 2 than the average temperature Ta.

  For example, when the electronic device 1B is a vehicle-mounted device and a vehicle equipped with the electronic device 1B is stored indoors in a very hot area, the actual storage temperature of the nonvolatile memory 2 is higher than the average temperature in the area. May be lower. Even in such a case, by correcting the average temperature Ta to the estimated storage temperature Tx, an error between the local average temperature Ta and the actual storage temperature of the nonvolatile memory 2 is reduced.

  As described above, the electronic device 1B according to Embodiment 3 includes the in-device temperature acquisition unit 15, the outside air temperature acquisition unit 16, and the temperature correction unit 17. The refresh interval acquisition unit 11B performs refresh corresponding to the number N of data rewrite executions of the nonvolatile memory 2 in the temperature range including the estimated storage temperature Tx corrected from the average temperature Ta by the temperature correction unit 17 from the refresh execution interval DB20. The execution interval Dx is acquired. By reflecting the estimated storage temperature Tx in the determination of the refresh execution interval Dx, the electronic device 1B can realize long-term data retention while suppressing a decrease in the data rewriting life of the nonvolatile memory 2.

  In the electronic device 1B according to Embodiment 3, the device internal temperature acquisition unit 15 acquires the temperature Ti inside the electronic device 1B at the timing when the electronic device 1B is activated. In general, in a high-functional electronic device such as a car navigation apparatus, the processing load of the device in the device and the operation condition vary depending on the operation mode or use condition, and the temperature Ti greatly varies. Therefore, the device internal temperature acquisition unit 15 acquires the temperature at the timing when the electronic device 1B is activated, thereby acquiring a stable temperature before being affected by variations in the processing load and operating conditions of the device in the device. Can do.

  It should be noted that the present invention is not limited to the above-described embodiment, and within the scope of the present invention, each free combination of the embodiments or any component modification or embodiment of the embodiment. It is possible to omit arbitrary components in each of the above.

  1, 1A, 1B electronic device, 2 nonvolatile memory, 3 memory management system, 4 network, 5 server device, 10 position information acquisition unit, 11, 11A, 11B refresh interval acquisition unit, 12 determination unit, 13 refresh execution unit, 14 storage temperature calculation unit, 15 device internal temperature acquisition unit, 16 outside air temperature acquisition unit, 17 temperature correction unit, 20 refresh execution interval DB, 20a first DB, 20b, 20c second DB, 100 GNSS receiver, 101 Nonvolatile memory, 102 processing circuit, 103 processor.

Claims (7)

An electronic device having a non-volatile memory,
A position information acquisition unit for acquiring position information of the electronic device;
Among the refresh execution intervals corresponding to the range of the data rewrite execution number of the nonvolatile memory in a plurality of temperature ranges, the temperature range includes the average temperature of the region corresponding to the position information acquired by the position information acquisition unit. A refresh interval acquisition unit for acquiring a refresh execution interval corresponding to the number of data rewrite execution times of the nonvolatile memory;
A determination unit that determines whether or not to perform refresh of the nonvolatile memory based on a refresh execution interval acquired by the refresh interval acquisition unit and an elapsed time from a previous refresh execution of the nonvolatile memory;
An electronic apparatus comprising: a refresh execution unit configured to perform refresh of the nonvolatile memory when the determination unit determines that refresh can be performed. An electronic device having a non-volatile memory,
A position information acquisition unit for acquiring position information of the electronic device;
The time from the previous refresh execution of the nonvolatile memory to the last activation of the electronic device, the elapsed time from the previous activation of the electronic device, the average temperature in the region corresponding to the location information acquired by the location information acquisition unit, And a storage temperature calculation unit that calculates an average storage temperature of the nonvolatile memory from the previous refresh execution of the nonvolatile memory using an average storage temperature of the nonvolatile memory until the previous refresh execution of the nonvolatile memory When,
The data in the nonvolatile memory in the temperature range including the average storage temperature calculated by the storage temperature calculation unit from the refresh execution interval corresponding to the range of the number of data rewrite execution times in the nonvolatile memory in a plurality of temperature ranges A refresh interval acquisition unit for acquiring a refresh execution interval corresponding to the number of rewrite executions;
A determination unit that determines whether or not to perform refresh of the nonvolatile memory based on a refresh execution interval acquired by the refresh interval acquisition unit and an elapsed time from a previous refresh execution of the nonvolatile memory;
An electronic apparatus comprising: a refresh execution unit configured to perform refresh of the nonvolatile memory when the determination unit determines that refresh can be performed. A device internal temperature acquisition unit for acquiring temperature information inside the electronic device;
An outside air temperature acquisition unit for acquiring temperature information outside the electronic device;
A temperature correction unit that corrects the average temperature based on temperature information acquired by the internal temperature acquisition unit and the outside air temperature acquisition unit;
The refresh interval acquisition unit is a refresh execution interval corresponding to a range of the number of data rewrite execution times of the nonvolatile memory in a plurality of temperature ranges, in a temperature range including the average temperature corrected by the temperature correction unit. The electronic apparatus according to claim 1, wherein a refresh execution interval corresponding to the number of data rewrite execution times of the nonvolatile memory is acquired. The electronic device according to claim 3, wherein the device internal temperature acquisition unit acquires temperature information inside the electronic device at a timing when the electronic device is activated. The electronic device according to claim 1, wherein the electronic device is mounted on a vehicle. An electronic device according to any one of claims 1 to 5,
A memory management system comprising: a database in which a refresh execution interval corresponding to the range of the average temperature for each region and the number of data rewrite execution times of the nonvolatile memory in a plurality of temperature ranges is registered. Computer
A position information acquisition unit that acquires position information of an electronic device having a nonvolatile memory;
Among the refresh execution intervals corresponding to the range of the data rewrite execution number of the nonvolatile memory in a plurality of temperature ranges, the temperature range includes the average temperature of the region corresponding to the position information acquired by the position information acquisition unit. A refresh interval acquisition unit for acquiring a refresh execution interval corresponding to the number of data rewrite execution times of the nonvolatile memory;
A determination unit that determines whether or not to perform refresh of the nonvolatile memory based on a refresh execution interval acquired by the refresh interval acquisition unit and an elapsed time from a previous refresh execution of the nonvolatile memory;
A program for causing a function to function as a refresh execution unit that performs refresh of the nonvolatile memory when the determination unit determines that refresh can be performed.

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