Electronic device, storage operation control method, and recording medium

Abstract

The present invention provides an electronic device, a storage operation control method, and a recording medium, which can operate more stably with respect to an external magnetic field. The electronic device (1) comprises a magnetic memory (13), a non-magnetic non-volatile memory (14), an acquisition unit for acquiring information about the magnetic field around the electronic device, and a CPU (11). When writing data to the magnetic memory (13), the CPU (11) stops writing the data to the magnetic memory (13) and writes the data to the non-volatile memory (14) if it is determined based on the acquired magnetic field information that a strong magnetic field with a magnetic field strength greater than a reference is applied to the electronic device. If there is data to be written to the non-volatile memory (14) when it is determined based on the acquired magnetic field information that no strong magnetic field is applied, the CPU (11) writes the data to the magnetic memory (13).

Description

[0001] This application claims priority based on patent application No. 2021-207805 filed in Japan on December 22, 2021, and incorporates all the contents of the basic application into this application. Technical Field

[0002] The present invention relates to an electronic device, a storage action control method and a recording medium. Background Art

[0003] In digital processing, such as in electronic computers, increasing data read and write speed, increasing capacity, and reducing costs are key issues. In addition to conventional volatile memory (RAM) and non-volatile memory, other methods have been designed and developed. Magnetic memory, such as MRAM (Magnetic Random Access Memory), is known as a storage method that requires no refresh, enables high-speed read and write operations similar to RAM, and has lower applied voltage and a longer lifespan than flash memory.

[0004] Magnetic memory uses a technique that controls the direction of magnetization by current to represent values ​​of 0 or 1. Compared to conventional memory, it is more susceptible to strong magnetic fields. In contrast, Japanese Patent Application Publication No. 2011-61374 discloses a technique for evacuating data from magnetic memory to another storage unit when a strong magnetic field is detected. Summary of the Invention

[0005] Magnetic memory is most susceptible to magnetic field effects during data writing. On the other hand, if new data is generated regardless of the magnetic field state, leaving the generated data as is will strain the capacity of the volatile memory and cause problems with stable operation.

[0006] An object of the present invention is to provide an electronic device, a storage operation control method, and a recording medium that can operate more stably with respect to an external magnetic field.

[0007] In order to achieve the above-mentioned object, the electronic device of the present invention comprises:

[0008] A first nonvolatile memory is a magnetic memory having no movable portion;

[0009] a second non-volatile memory, which is a non-magnetic memory;

[0010] an acquisition unit that acquires information on a magnetic field around the electronic device; and

[0011] Control Department,

[0012] When the control unit determines that a strong magnetic field with a magnetic field strength greater than a baseline is applied to the electronic device based on the information of the magnetic field obtained by the acquisition unit when writing data to the first non-volatile memory, the control unit terminates writing of the data to the first non-volatile memory and writes the data to the second non-volatile memory. When the control unit determines that the strong magnetic field is not applied based on the information of the magnetic field obtained by the acquisition unit, if there is data to be written to the second non-volatile memory, the data is written to the first non-volatile memory.

[0013] According to the present invention, there is an effect of enabling an electronic device to operate more stably with respect to an external magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram showing the functional structure of an electronic device.

[0015] Figure 2 This is a diagram illustrating the influence of an external magnetic field on a magnetic memory.

[0016] Figure 3 This is a flowchart showing the control steps of the write control process. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] Figure 1 1 is a block diagram showing the functional configuration of the electronic device 1 according to the present embodiment.

[0019] The electronic device 1 is a small portable terminal device (computer) such as an electronic clock or a smart watch, and includes a CPU 11 (Central Processing Unit) (control unit), a RAM 12 (Random Access Memory), a magnetic memory 13 (a first non-volatile memory), a non-volatile memory 14 (a second non-volatile memory), a display unit 15, an operation receiving unit 16, a communication unit 17, a magnetic field sensor 18, and a power supply unit 19.

[0020] The CPU 11 is a hardware processor that performs calculations and generally controls the operation of the electronic device 1. The CPU 11 may be a plurality of CPUs that perform processing in parallel. Parallel processing can be performed by distributing a single processing content or performing different processing independently.

[0021] The RAM 12 provides a memory space for working and stores temporary data to the CPU 11. The RAM is, for example, a DRAM, and a part or all of the RAM may be an SRAM.

[0022] The magnetic memory 13 is a magnetic storage medium (without a movable portion), such as a well-known magnetoresistive memory (including memory using MRAM and MTJ (Magnetic Tunnel Junction)). It is a non-volatile memory, but in the electronic device 1, it is used for both the retention of data as a conventional non-volatile memory and for access to temporary data in processing, etc. as part of the conventional volatile memory usage. The non-volatile memory 14 is a non-magnetic non-volatile memory, such as a flash memory (SSD; including a solid state drive).

[0023] Generally, the reading and writing of data by the magnetic memory 13 is faster than that of a typical non-volatile memory 14 such as a flash memory, and in particular, the power consumption during writing is low. Therefore, the magnetic memory 13 stores data that is assumed to be frequently referenced and updated in the magnetic memory 13, and also stores programs 131 and changed settings that are temporarily expanded in the RAM 12 after reading. The non-volatile memory 14 stores initial setting data that is rarely referenced except during initialization. As to whether the stored data is written to the magnetic memory 13 or the non-volatile memory 14, it can be set (determined) according to the content.

[0024] The nonvolatile memory 14 is divided (defined) into a normal storage unit 141 (first storage area) and an alternative storage unit 142 (second storage area). As described above, the normal storage unit 141 stores and retains selected data to be stored in the nonvolatile memory 14. As described later, the alternative storage unit 142 temporarily stores selected data to be stored in the magnetic memory 13.

[0025] The display unit 15 includes a display screen and displays various information on the display screen under the control of the CPU 11. The display screen is not particularly limited and may be, for example, a liquid crystal display (LCD) or an organic EL screen. Alternatively, the display unit 15 may include an LED light, etc., which can be lit or flashed to indicate predetermined information.

[0026] The operation accepting unit 16 accepts input operations from the outside and outputs the accepted contents as input signals to the CPU 11. The operation accepting unit 16 includes, for example, some or all of push button switches, rotary switches, slide switches, rocker switches, and a touch panel superimposed on a display screen.

[0027] The communication unit 17 includes an antenna and a transceiver circuit, and controls communication with external devices to transmit and receive data. The communication standards that the communication unit 17 can control are not particularly limited; examples include Bluetooth (registered trademark), wireless LAN, and infrared communication. Communication based on multiple communication standards can be used in combination or selectively. The transceiver circuit performs processing such as modulation and demodulation of transmitted and received data and encoding and decoding of digital data.

[0028] The magnetic field sensor 18 measures the magnetic field and outputs the measurement results to the CPU 11. The magnetic field sensor 18 has a measurement range that can detect at least a reference magnetic field strength slightly lower than a level that may cause problems during the write operation of the magnetic memory 13. The magnetic field sensor 18 can be a sensor that only obtains magnetic field strength, or it can be a sensor that can measure the magnetic field vector components in three mutually orthogonal axis directions. The three axes can also be determined based on the direction of the magnetic field applied to the magnetic memory 13. The magnetic field sensor 18 can be located near the magnetic memory 13, or it can be located near a housing (not shown) that is omitted for easy measurement of the external magnetic field.

[0029] The power supply unit 19 supplies power at a predetermined voltage to each component of the electronic device 1. While not particularly limited, the power supply unit 19 includes a secondary battery 191, converts the power output from the secondary battery 191 into an appropriate voltage, and outputs the converted power. The secondary battery 191 can be charged by external power supply, with charging and discharging controlled by the power charging control unit 192, for example, depending on whether the power supply terminal is connected to an external terminal or whether a predetermined voltage is applied.

[0030] Next, the storage operation control of the magnetic memory 13 in the electronic device 1 of this embodiment will be described.

[0031] The MRAM, which is the magnetic memory 13 of this embodiment, writes data by reversing the magnetization of a ferromagnetic layer using an electric current. The magnetization state is affected by the application of a strong external magnetic field (when a strong magnetic field is present). In particular, when an excessive magnetic field is applied during data writing, the magnetization state becomes incorrect, resulting in the writing of erroneous data.

[0032] Figure 2 This is a diagram for explaining the influence of an external magnetic field on the magnetic memory 13 .

[0033] The lower limit BL of the magnetic field strength that adversely affects data when writing data to the magnetic memory 13 is significantly lower than the lower limit BH of the magnetic field strength that adversely affects the data itself when reading or storing it. As a result, compared to magnetic field strengths above the lower limit BH that are difficult to generate without actively bringing a strong magnet or the like into proximity, the magnetic field strengths above the lower limit BL of the former can be included in the range that is often generated when using a portable electronic device. The lower limit BL depends on the magnetic memory 13, for example, the magnetic field is about 2000A / m (the magnetic flux density is about 2.6mT, about 50-120 times the Earth's magnetic field). The reference intensity Bth (reference magnetic field intensity) of the magnetic field used to determine the risk of writing can also be lower than the lower limit BL, for example, it can be about 50-90% of the lower limit BL. That is, the reference intensity Bth is the magnetic field intensity at a level that does not cause problems (abnormalities) for the data already stored in the magnetic memory 13.

[0034] In the electronic device 1 of this embodiment, the magnetic field that may affect the writing to the magnetic memory 13 is measured, or the presence or absence of a state (action) that may generate such a magnetic field (strong magnetic field) is obtained as magnetic field information, and the writing to the magnetic memory 13 is terminated based on the magnetic field information.

[0035] In this case, if the state of suspending writing to the magnetic memory 13 continues, the amount of data temporarily stored in the RAM as data stored in the magnetic memory 13 during this period increases. For example, when obtaining a history of continuous or intermittent measurement results, the capacity of the RAM is compressed, which may eventually cause problems with the operation of the normal RAM 12. Therefore, during the period of suspending writing to the magnetic memory 13, the alternative storage unit 142 of the non-volatile memory 14 temporarily stores the data held by the RAM 12, and after writing to the magnetic memory 13 becomes possible, the data is read from the alternative storage unit 142 and written to the magnetic memory 13.

[0036] The magnetic field considered here may include, for example, not only proximity to external permanent magnets, products that generate strong magnetic fields, factories, etc., but also actions of the electronic device 1 itself that generate magnetic fields, such as communication actions and charging actions. In addition, in a combination of these, such as when the charging connector of an external device has a magnet and the electronic device 1 is fixed by the charging connector during the charging action, although the charging action itself does not generate a strong magnetic field, since the charging action is equivalent to the proximity of the charging connector to the magnet, the charging action can be considered as an action approaching a strong magnetic field. Therefore, in the electronic device 1, in addition to the direct magnetic field measurement performed by the magnetic field sensor 18, the presence or absence of the communication action, the presence or absence of the charging action, etc. can also be included in the information on the surrounding magnetic field (magnetic field information). Therefore, together with the magnetic field sensor 18, the CPU 11 that obtains the operation status from the communication unit 17 and the power supply unit 19 also constitutes the acquisition unit of this embodiment.

[0037] In addition, such information related to the presence or absence of an action may be obtained by the CPU 11 as magnetic field information, including the advance notice information, before the action is about to start, rather than after the actual start of the action. Thus, the generation of write errors to the magnetic memory 13 caused by the strong magnetic field can be more reliably suppressed, and various processing including the storage action of data can be stably performed.

[0038] Figure 3 This is a flowchart showing the control procedure performed by the CPU 11 including the write control process of the storage operation control method according to this embodiment. This process is started by reading the program 131 when data is written to the magnetic memory 13.

[0039] When the write control process begins, the CPU 11 obtains magnetic field information such as the measurement results of the magnetic field sensor 18 (step S101). The CPU 11 determines whether the magnetic field is estimated to be above the reference intensity (a strong magnetic field is applied to the device, particularly the magnetic memory 13) (step S102). As described above, it is not necessary to directly measure the magnetic field during the execution of communication and charging operations. It is sufficient to pre-set that a strong magnetic field is applied based on the results of previous experiments on the electronic device 1.

[0040] If it is determined that a strong magnetic field is being applied ("Yes" in step S102), CPU 11 determines whether the data to be written exists in RAM 12 (step S103). If it is determined that the data to be written does not exist in RAM 12 ("No" in step S103), CPU 11 ends the write control process.

[0041] When it is determined that the data to be written exists in RAM 12 ("Yes" in step S103), CPU 11 stops the write operation to magnetic memory 13 and starts the process of writing the data to be written to the alternative storage unit 142 of non-volatile memory 14 (step S104; first control unit). In addition, in the case of a sharp increase in magnetic field intensity, the last data written to magnetic memory 13 may have been affected by the strong magnetic field, so CPU 11 can also slightly trace back the data written to magnetic memory 13 and write it to the alternative storage unit 142. CPU 11 is set to write data to the non-volatile memory 14 as an alternative (step S105). At this time, CPU 11 writes and stores information such as the write object address (write position) in the magnetic memory 13 that replaces the write data. Then, the processing of CPU 11 returns to step S101.

[0042] If it is determined in the determination process of step S102 that a strong magnetic field is not being applied ("No" in step S102), the CPU 11 determines whether alternative write data has been set (step S111). If it is determined that alternative write data has been set ("Yes" in step S111), the alternative write data is read from the alternative storage unit 142 of the non-volatile memory 14 and, based on the write target address stored in the process of step S105, the operation of writing to the set position of the magnetic memory 13 is started (step S112; second control unit). The process of the CPU 11 then returns to step S101.

[0043] If it is determined that no alternative write data has been set ("No" in step S111), the CPU 11 determines whether the write target data exists in the RAM 12 (step S113). If it is determined that the write target data does not exist in the RAM 12 ("No" in step S113), the CPU 11 ends the write control process.

[0044] If it is determined that the write target data exists in RAM 12 ("Yes" in step S113), CPU 11 writes the write target data into magnetic memory 13 (step S114). CPU 11 sets that there is no alternative write data (step S115). Then, the processing of CPU 11 returns to step S101.

[0045] As described above, the electronic device 1 of this embodiment includes: a magnetic memory 13; a non-magnetic non-volatile memory 14; an acquisition unit for acquiring magnetic field information within and / or around the device (a magnetic field sensor 18; a CPU 11 for acquiring information related to the operation of a communication unit 17, a power supply unit 19, and the like that generate the magnetic field of the device); and a CPU 11. When the CPU 11 determines, based on information acquired by the acquisition unit when writing data to the magnetic memory 13, that a strong magnetic field associated with the presence of a magnetic field strength exceeding a reference level is being applied, the CPU 11 halts writing of target data to the magnetic memory 13 and writes the data to the non-volatile memory 14. When the CPU 11 determines, based on information acquired by the acquisition unit, that a strong magnetic field is not being applied, the CPU 11 writes the data to the magnetic memory 13, even if there is data to be written to the non-volatile memory 14.

[0046] In this way, compared to retaining and reading data in the magnetic memory 13, a write operation with a low magnetic field strength that causes abnormal operation and a process that temporarily replaces the storage and retention of written data can be performed, thereby limiting the magnetic field shielding capability of the magnetic memory 13 to an appropriate level, thereby suppressing increases in the manufacturing cost, size, and weight of the electronic device 1. In particular, by being able to temporarily suspend the write operation, the restrictions on the positional relationship between the magnetic memory 13, the power supply unit 19, and the communication unit 17 in the electronic device 1 can be reduced, thereby more efficiently achieving miniaturization and multifunctionality of the electronic device 1.

[0047] In addition, the acquisition unit obtains the presence or absence of at least one of the charging action and the communication action of the electronic device 1 as information, and the CPU 11 determines that a strong magnetic field is applied when the action is performed. In the case where the action of the device, the proximity and positional relationship to the external magnet related to the action, and the magnitude of the generated magnetic field are roughly determined, it is known that a magnetic field that may become a problem is generated simply by the presence or absence of the action. Therefore, it is possible to appropriately obtain information related to the presence or absence of a strong magnetic field without performing magnetic field measurement. In addition, in this case, including the case where it is possible to obtain advance information on the generation of a strong magnetic field before the strong magnetic field is actually generated, that is, before starting these communication actions and charging actions, it is possible to more reliably suppress the occurrence of write errors to the magnetic memory 13.

[0048] Furthermore, the acquisition unit includes a magnetic field sensor 18. By actually measuring the magnetic field, the influence of an unexpectedly strong magnetic field such as an external magnetic field can be quickly detected, and the writing process to the magnetic memory 13 can be stopped.

[0049] Furthermore, when the CPU 11 writes data to be written to the magnetic memory 13 into the non-volatile memory 14, it also stores information related to the write position of the data in the magnetic memory 13. If it is determined that a strong magnetic field is not being applied, and if there is data to be written to the non-volatile memory 14, the CPU 11 writes the data written to the non-volatile memory 14 into the magnetic memory 13 based on the information related to the write position. This allows the data written directly to the magnetic memory 13 and the data written via the non-volatile memory 14 to be appropriately matched in terms of the write order, and makes it easy to subsequently read the data from the magnetic memory 13.

[0050] Furthermore, the CPU 11 can also determine whether to store the retained data in the magnetic memory 13 or in the non-volatile memory 14, and can separately determine a normal storage unit 141 for the data retained by the non-volatile memory 14 and an alternative storage unit 142 for temporarily writing the data retained by the magnetic memory 13 in the non-volatile memory 14. In this way, the non-volatile memory 14 is not used merely as a backup for the magnetic memory 13, but is used separately from the magnetic memory 13 to store and retain the data as appropriate, thereby enabling more efficient data storage and stable operation of the electronic device 1.

[0051] In addition, in the storage action control method for the magnetic memory 13 of the present embodiment using the magnetic memory 13 and the non-volatile memory 14, when it is determined that a strong magnetic field related to a magnetic field strength higher than a baseline in the local machine is applied when writing data to the magnetic memory 13, the writing of the write object data to the magnetic memory 13 is terminated and the data is written to the non-volatile memory 14. When it is determined that no strong magnetic field is applied, if there is write object data to be written to the non-volatile memory 14, the data is written to the magnetic memory 13.

[0052] In this way, when writing to the magnetic memory 13, the writing to the magnetic memory 13 is selectively terminated according to the magnetic field strength and the data is stored in the non-volatile memory 14 instead. After the magnetic field strength is sufficiently reduced, the stored data is written to the magnetic memory 13 instead. This allows the RAM 12 to operate stably without compressing its capacity, and the data written to the magnetic memory 13 can be properly maintained.

[0053] Furthermore, by installing the program 131 related to the storage operation control method and executing it in software, the electronic device 1 including the magnetic memory 13 can be easily operated more stably without requiring any special additional hardware configuration.

[0054] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, in the above-described embodiment, the replacement write data written to the magnetic memory 13 is directly placed in the non-volatile memory 14 (overwritten when other data is written), but the replacement write data written to the magnetic memory 13 can also be deleted from the non-volatile memory 14.

[0055] In the above embodiment, the nonvolatile memory 14 is completely divided into the normal storage unit 141 and the alternative storage unit 142. However, this does not necessarily have to be the case. In this case, the normal write operation can be limited so as to ensure a capacity comparable to that of the magnetic memory 13 as an area for storing alternative write data.

[0056] In addition, in the above embodiment, the communication action and the charging action are included in the magnetic field information, but one or both of them may be excluded from the magnetic field information. Alternatively, the magnetic field information may include only a portion of the communication action related to the communication standard. Furthermore, in the case of an electronic device that generates a strong magnetic field in addition to the communication and charging actions, information related to the execution of this action may also be included in the magnetic field information.

[0057] Furthermore, in the absence of a strong magnetic field, when there is both alternative write data stored in the alternative storage unit 142 and data subsequently stored from the RAM 12 in the magnetic memory 13, the above embodiment describes a case where the alternative write data is first written to the magnetic memory 13, but the present invention is not limited thereto. Alternatively, by writing the data previously stored in the RAM 12 to the magnetic memory 13, the data written to the magnetic memory 13 can be retained in the RAM 12 without occupying storage capacity. Furthermore, in cases where data is intermittently written to the magnetic memory 13 from the RAM 12, the alternative write data can be written to the magnetic memory 13 during the writing period from the RAM 12 to the magnetic memory 13.

[0058] Furthermore, the magnetic field sensor 18 may be used in conjunction with a normal geomagnetic field sensor as long as a necessary measurement intensity width can be obtained.

[0059] Furthermore, in the above embodiment, the electronic device 1 is described as being portable, but the present invention is not limited thereto and may be a stationary electronic device (including an electronic device that can be transported as needed).

[0060] In addition, in the above description, as the computer-readable medium of the program 131 involved in the write control to the magnetic memory 13 of the present invention, magnetic memory 13 is enumerated as an example and described, but is not limited to this. It can also be stored in the non-volatile memory 14 such as the flash memory including SSD. As the computer-readable medium of other non-magnetic methods, removable recording media such as other non-volatile memories, CD-ROM, DVD disks such as FeRAM (ferroelectric memory) can be applied. In addition, as the medium for providing the data of the program involved in the present invention via a communication line, carrier wave (carrier wave) is also applicable to the present invention.

[0061] Furthermore, the specific configurations, contents of processing operations, steps, and the like shown in the above-described embodiments can be appropriately modified without departing from the spirit of the present invention.

[0062] Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the scope of claims and the scope equivalent thereto.

Claims

1. An electronic device, characterized in that: have: A first nonvolatile memory is a magnetic memory having no movable portion; a second non-volatile memory, which is a non-magnetic memory; an acquisition unit that acquires information on a magnetic field surrounding the electronic device; as well as Control Department, When the control unit determines that a strong magnetic field having a magnetic field strength greater than a reference value is applied to the electronic device based on the information about the magnetic field obtained by the acquisition unit when writing data to the first non-volatile memory, the control unit stops writing the data to the first non-volatile memory and writes the data to the second non-volatile memory. When the control unit determines that the strong magnetic field is not applied based on the information about the magnetic field obtained by the acquisition unit, the control unit writes the data to the first non-volatile memory if there is data to be written to the second non-volatile memory. The presence or absence of charging of the electronic device by a charging connector having a magnet of an external device is acquired as the information on the magnetic field, and when the charging operation is in progress, it is determined that the strong magnetic field is being applied to the electronic device.

2. The electronic device according to claim 1, wherein The acquisition unit acquires whether or not the electronic device is in communication operation as the magnetic field information. The control unit determines that the strong magnetic field is applied when the communication operation is performed.

3. The electronic device according to claim 1 or 2, characterized in that: The acquisition unit includes a magnetic field sensor that acquires information on the magnetic field.

4. The electronic device according to claim 1 or 2, characterized in that: When the control unit writes the data to the second non-volatile memory, it also stores information related to the write position of the data in the first non-volatile memory. When it is determined that the strong magnetic field is not applied, if there is data to be written to the second non-volatile memory, the control unit writes the data to the first non-volatile memory based on the information related to the write position.

5. The electronic device according to claim 1 or 2, characterized in that: The control unit determines whether to store the retained data in the first nonvolatile memory or the second nonvolatile memory, A first storage area for storing data stored in the second nonvolatile memory and a second storage area for temporarily writing data stored in the first nonvolatile memory are defined in the second nonvolatile memory.

6. The electronic device according to claim 2, wherein: The control unit obtains information on the magnetic field including advance information immediately before starting the charging operation.

7. A method for controlling a storage operation in a first nonvolatile memory of an electronic device, wherein the electronic device comprises a first magnetic nonvolatile memory having no movable portion and a second nonvolatile nonvolatile memory having a nonmagnetic structure, wherein: When writing data to the first non-volatile memory, if it is determined that a strong magnetic field having a magnetic field strength greater than a reference value is applied to the electronic device, the writing of the data to the first non-volatile memory is stopped and the data is written to the second non-volatile memory; if it is determined that the strong magnetic field is not applied, the data is written to the first non-volatile memory if there is data to be written to the second non-volatile memory. The presence or absence of charging of the electronic device by a charging connector having a magnet of an external device is acquired as the information on the magnetic field, and when the charging operation is in progress, it is determined that the strong magnetic field is being applied to the electronic device.

8. A computer-readable non-transitory recording medium, characterized in that: A program is recorded, the program causing a computer of an electronic device including a first magnetic nonvolatile memory having no movable portion and a second nonvolatile nonvolatile memory having a nonmagnetic type to execute the following means: a first control unit that, when writing data into the first nonvolatile memory, determines that a strong magnetic field having a magnetic field strength greater than a reference value is applied to the electronic device, stops writing the data into the first nonvolatile memory and writes the data into the second nonvolatile memory; as well as The second control unit, when it is determined that the strong magnetic field is not applied, writes the data to the first nonvolatile memory if there is the data to be written to the second nonvolatile memory, The presence or absence of charging of the electronic device by a charging connector having a magnet of an external device is acquired as the information on the magnetic field, and when the charging operation is in progress, it is determined that the strong magnetic field is being applied to the electronic device.

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