JP2006039876A - Data storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a necessary storage area, while securing reliability in storage data, even when a power source is interrupted during writing in a non-volatile memory. <P>SOLUTION: An air-conditioner ECU 40 includes a CPU 44; and an EEPROM 45 for electrically rewriting a storage content. When control data is updated, writing is performed in the EEPROM 45 by defining the updated control data and numerical data, which is changed in response to a prescribed rule, as a group. The EEPROM 45 holds at least three groups of numerical data and control data which become older in order from the latest. Consequently, it is determined whether the control data is normally written or not through the use of the regularity of the numerical data, so that the necessary storage capacity is reduced, while securing the reliability in the control data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data storage device.

  Conventionally, there has been proposed a semiconductor memory device capable of effectively holding data to be stored even when the power is cut off during data writing (see, for example, Patent Document 1). In the semiconductor memory device disclosed in Patent Document 1, the data to be stored is a set of backup data and its mirror data, and this one set of backup data and its mirror data is stored in an EEPROM as a nonvolatile memory. Write sequentially to at least two storage areas.

  For example, a set of backup data and its mirror data are stored in three locations every 30 addresses in the EEPROM. As an example, backup data is stored at addresses 0, 30, and 60, and mirror data is stored at addresses 1, 31, and 61.

The data writing process to the EEPROM is executed by individually writing commands to these six addresses. For this reason, even if the supply of power to the EEPROM is interrupted during the above-described process of writing a set of backup data and mirror data, only the address data written at the time of the interruption becomes invalid, and other addresses are stored. Holds data after update or data before update.
Japanese Patent Laid-Open No. 9-293028

  However, in the conventional apparatus, the backup data is stored in at least two, preferably three, addresses in order to retain the data to be stored regardless of the interruption of the power supply during the writing process. Further, in order to ensure the reliability of the backup data, the same number of mirror data of the backup data is stored.

  Therefore, a large number of storage areas are required to store one backup data. Therefore, if the number of data to be stored increases, the storage capacity required in the nonvolatile memory will become enormous.

  The present invention has been made in view of the above points, and even when a power interruption occurs during writing to a nonvolatile memory, a necessary storage area is secured while ensuring the reliability of stored data. It is an object to provide a data storage device that can be reduced.

In order to achieve the above object, a data storage device according to claim 1 comprises:
Non-volatile memory that can electrically rewrite the memory contents,
A data writing means for writing predetermined storage data into the nonvolatile memory;
A data storage device configured to retain stored data even when the power is turned off,
The data writing means has numerical data generating means for generating numerical data that changes according to a predetermined rule every time the stored data is written within a predetermined numerical range, and sets the numerical data and the stored data as a set in the nonvolatile memory. Write,
The nonvolatile memory has an area for storing at least three sets of numerical data and storage data, and
Determining means for reading at least three sets of numerical data and stored data stored in a non-volatile memory and comparing the numerical data in the data to determine whether the numerical data is changing according to a predetermined rule; Prepared,
When it is determined by the determination means that the numerical data is changing according to a predetermined rule, the latest numerical data in the numerical data is specified, and the storage data corresponding to the latest numerical data is set as the latest stored data. Features.

  As described above, in the data storage device according to the first aspect, in order to determine whether or not the stored data is correctly written, numerical data that changes according to a predetermined rule every time the stored data is written is used. Here, when it is determined that the numerical data stored in the nonvolatile memory is changed according to a predetermined rule as a result of mutual comparison, it is considered that the numerical data is correctly written in the nonvolatile memory. The stored data is paired with the numerical data and written to the non-volatile memory at approximately the same time. Therefore, if the numerical data is normally written, the stored data may have been written normally. high. For this reason, it is possible to determine whether or not the stored data is correctly written using numerical data. Therefore, the reliability of stored data can be ensured even when the power supply is interrupted during writing to the nonvolatile memory.

  By using numerical data, there is no need to write in a plurality of locations in the nonvolatile memory in order to store one piece of stored data as in the prior art. As a result, it is possible to reduce a storage area for storing data to be saved, as compared with the conventional case.

  According to a second aspect of the present invention, it is preferable that a control unit for controlling the in-vehicle device mounted on the vehicle is provided, and the stored data is control data used by the control unit for controlling the in-vehicle device. Normally, the on-vehicle equipment mounted on the vehicle and its control unit stop supplying power when the ignition switch is turned off. Since it cannot be predicted when the ignition switch is turned off by the driver of the vehicle, it is preferable to employ the above-described configuration in order to store control data used by the control unit to control the in-vehicle device.

  As described in claim 3, the data size of the numerical data is preferably smaller than the data size of the stored data. Thereby, the required storage capacity in the nonvolatile memory can be further reduced.

  The data writing means stores the oldest set of numerical data and stored data so that the nonvolatile memory can store at least the latest three sets of numerical data and stored data. It is preferable to overwrite the latest set of numerical data and stored data in the area. In this way, by overwriting the latest set of numerical data and storage data with respect to the oldest set of numerical data and storage data, the size of the necessary storage area is always kept small, and the latest at least 3 A set of numerical data and stored data can be stored.

  According to a fifth aspect of the present invention, the data writing means preferably writes the storage data and numerical data in the nonvolatile memory in this order. When writing numerical data in the order of stored data to the nonvolatile memory, if the power is turned off while the stored data is being written after the numerical data is written, the numerical data is written normally, but the stored data is written abnormally. It can be done. In this case, although the numerical data changes in accordance with a predetermined rule, an abnormality occurs in the stored data. Such a problem can be prevented by writing the stored data and the numerical data in the nonvolatile memory in this order.

  According to the sixth aspect of the present invention, the initial value in the numerical range is stored in all the areas storing the numerical data before the first set of numerical data and stored data is written by the data writing means. It is preferably written. Thereby, even before at least three sets of numerical data and stored data are written in the non-volatile memory, the determination means reads the initial value as numerical data, and determines whether the numerical data changes according to a predetermined rule. Can be determined.

  The data writing means preferably writes the initial value in the nonvolatile memory when the numerical data to be written next exceeds a limit value in a predetermined numerical range. Thereby, in the predetermined numerical range, the numerical data can repeat the change according to the predetermined rule every time the stored data is written.

  Preferably, the determination means determines that the numerical data changes according to a predetermined rule when the numerical data includes a limit value and an initial value. Thereby, the determination means can prevent erroneously determining that it has not changed according to a predetermined rule when the limit value and the initial value are compared with each other.

  As described in claim 9, the determination means performs a mutual comparison of the numerical data three times in total by sequentially selecting and comparing the two numerical data from the three numerical data. In a total of three inter-comparisons, when it is determined twice that the numerical data has changed according to a predetermined rule, it is considered that the writing of three sets of numerical data and stored data is normal, and three sets of numerical values It is preferable that the latest numerical data is specified from the data and the stored data, and the storage data corresponding to the latest numerical data is the latest stored data.

  If all three numerical data are written correctly, the two numerical data are selected from the three numerical data in sequence and the numerical data is compared three times in total. In the comparison between the previous numerical data and the previous numerical data, changes according to a predetermined rule are shown. On the other hand, in the comparison between the latest numerical data and the previous numerical data, changes different from the predetermined rule are shown. In this way, in the mutual comparison of the numerical data for a total of three times, when it is determined twice that the numerical data is changing according to a predetermined rule, all three numerical data are correctly written. Can be considered.

  As described in claim 10, when a determination is made that the numerical data has changed in accordance with a predetermined rule in a total of three intercomparisons, writing of one set of numerical data and stored data is abnormal. However, the writing of two sets of numerical data and stored data is considered normal, and the latest numerical data is specified from the two sets of numerical data and stored data, and the stored data corresponding to the latest numerical data Is the latest stored data.

  If the writing of one numerical data is abnormal among the three numerical data, the one numerical data is compared with the other two numerical data, respectively. This determination is made twice. In other words, if writing of one numerical data out of three numerical data is abnormal, it is determined only once that it has changed according to a predetermined rule.

  However, in this case, it is considered that two of the three numerical data are normally written. Therefore, by specifying the latest numerical data in the two numerical data, the memory corresponding to the latest numerical data is stored. The data can be the latest stored data. In this case, although there is a possibility that it is not actually the latest stored data, at least the previous stored data is the latest stored data.

  As described above, by using at least three numerical data, even if an abnormality occurs in one numerical data, it is possible to hold the latest stored data or stored data approximate thereto.

  As described in claim 11, when it is determined that the numerical data is not changed in accordance with a predetermined rule in three times of total comparison, writing of three sets of numerical data and stored data is abnormal. It is preferable that the default data set in advance be the latest stored data.

  In a total of three mutual comparisons, it is determined that the numerical data is not changed according to a predetermined rule three times because there is an abnormality in at least two numerical data. In this case, since it cannot be specified which numerical data is normal, it is considered that writing of the three sets of numerical data and stored data is abnormal. Since the latest stored data cannot be specified from the stored data, the default data set in advance is set as the latest stored data.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present embodiment, an example will be described in which the data storage device is applied to an automatic air conditioner control device 100 as a vehicle control device. When the occupant sets the temperature in the passenger compartment to a desired temperature, the automatic air conditioner control device 100 automatically adjusts the air outlet temperature, the air volume, the air blowing pattern, etc. of the air conditioning system according to the temperature outside the passenger compartment and the intensity of solar radiation. It is a system that automatically corrects the influence and controls the vehicle interior temperature to be kept constant. FIG. 1 is a block diagram showing a schematic configuration of an automatic air conditioner control apparatus 100 according to the present embodiment. Hereinafter, the automatic air conditioner control apparatus 100 according to the present embodiment will be described in detail.

  As shown in FIG. 1, a switch input circuit 10, a sensor input circuit 20, and a panel display circuit 30 are connected to the air conditioner ECU 40 of the automatic air conditioner control device 100. Further, a motor drive circuit 50, a relay drive circuit 60, and an air volume adjusting power transistor drive circuit 70 are connected.

  The switch input circuit 10 is a circuit that inputs a switch signal corresponding to an operation of an operation panel (not shown) of the automatic air conditioner to the air conditioner ECU 40. For example, in addition to the temperature setting switch, the operation panel is provided with an air conditioner switch for turning on / off the compressor, an air volume adjustment switch, a blowout port changeover switch, an outside air introduction switch, an inside air circulation changeover switch, and the like. When any one of these switches is operated, a switch signal corresponding to the operation is input to the air conditioner ECU 40.

  The sensor input circuit 20 is composed of an A / D conversion circuit or the like, and changes the detected value of the inside / outside air temperature sensor that detects the temperature inside and outside the vehicle interior, the detected value of the solar radiation sensor that detects the amount of solar radiation, etc. into a digital signal. Input to the ECU 40.

  The panel display circuit 30 is a circuit that displays display contents based on a display signal input from the air conditioner ECU 40 on a display device (not shown) of the operation panel. For example, the air conditioner ECU 40 displays the temperature set by the occupant, the outside air temperature detected by the outside air temperature sensor, the air volume, the wind blowing pattern, and the like on the display device of the operation panel.

  Next, the configuration of the air conditioner ECU 40 of the automatic air conditioner control device 100 will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the air conditioner ECU 40 according to the present embodiment. As shown in the figure, the air conditioner ECU 40 includes a constant voltage circuit 43, a CPU 44, an EEPROM 45, and a serial communication line 46, and is supplied with electric power from a battery 41 mounted on the vehicle via a key switch 42. Operate.

  The key switch 42 is provided to supply or cut off the power of the battery 41 to the automatic air conditioner control device 100. By turning on the key switch 42, the automatic air conditioner control device 100 can operate by receiving power supplied from the battery 41. The key switch 41 includes a switch that is automatically turned on when the engine is started, a switch that is directly operated by the user, and the like.

  The constant voltage circuit 43 receives a 12V DC voltage from the battery 41 via the key switch 42 and generates a 5V constant voltage.

  The CPU 44 executes various arithmetic processes according to a predetermined program, and calculates control signals for controlling a motor drive circuit 50, a relay drive circuit 60, and an air volume adjusting power transistor drive circuit 70 described later. Specifically, the CPU 44 calculates control signals for the drive circuits 50, 60, and 70 based on switch signals from the operation panel of the auto air conditioner and sensor signals from sensors installed in various places.

  The EEPROM 45 is one type of nonvolatile memory that can electrically rewrite the stored contents. The EEPROM 45 includes control data (for example, set temperature data, air conditioner switch on / off data, etc.) used in the control of the auto air conditioner and numerical data that changes according to a predetermined rule every time the control data is updated. For each type of control data, at least three sets of numerical data and control data are stored. The EEPROM 45 is connected to a CPU 44 via a serial communication line 46, and data is written and read by the CPU 44.

  The above-described control data may be updated when the automatic air conditioner control is executed. When the auto air conditioner control is executed after the key switch 42 is turned off and turned on again, it is necessary to start the control according to the latest control data updated at the time of the previous auto air conditioner control execution. Therefore, the CPU 44 backs up the control data by storing the control data in the EEPROM 45. Immediately after the key switch 42 is turned on, the CPU 44 reads the control data stored in the EEPROM 45 and starts the automatic air conditioner control based on the control data.

  The motor drive circuit 50 is a circuit that performs forward / reverse motor switching, stop at a target position, and overcurrent protection (motor voltage cut-off) when the motor is locked for each servo motor used in an automatic air conditioner. . Specifically, the motor drive circuit 50 includes an air mix opening degree adjusting servo motor for adjusting the blowing temperature, a blowout port switching servo motor, and a suction port switching servo motor based on a control signal from the air conditioner ECU 40. Control.

  The relay drive circuit 60 controls energization to the electromagnetic clutch that switches connection / disconnection between the compressor and the engine based on a control signal from the air conditioner ECU 40. Specifically, when the air conditioner switch is turned on, the air conditioner ECU 40 outputs a control signal for connecting the compressor and the engine, and in response to this, the relay drive circuit turns on the relay switch in the energization circuit of the electromagnetic clutch. To do. As a result, the electromagnetic clutch is operated, and the compressor is driven by the rotation of the engine.

  The air volume adjusting power transistor drive circuit 70 is a circuit that converts the air volume signal output as a digital signal from the air conditioner ECU 40 into an analog signal and controls the speed adjusting power transistor of the blower. As a result, the amount of air sent from the outlet to the vehicle compartment is controlled.

  Next, the writing of numerical data and control data to the EEPROM 45 in this embodiment will be described.

  In the present embodiment, the latest data for each type of control data is maintained so that the control data backup function by the EEPROM 45 is maintained even if one control data written in the storage area of the EEPROM 45 is abnormal. In addition to the one set of numerical data and control data, at least two sets of previous numerical data and control data are stored. That is, in the EEPROM 45, an area for storing at least the latest and past three sets of numerical data and control data is secured for each control data.

  The CPU 44 generates numerical data that changes according to a predetermined rule every time the control data is written, and writes the numerical data in the EEPROM 45 together with the control data. At this time, the CPU 44 reads the numerical data already written in the EEPROM 45, and generates the numerical data to be written next, which changes according to a predetermined rule, based on the numerical data. Furthermore, the oldest set of numerical data and control data is specified from the read numerical data, and the latest set of numerical data and control data is written so as to overwrite it. Thus, the EEPROM 45 can always store at least three sets of numerical data and storage data that become older in order from the latest one, while keeping the size of the necessary storage area small.

  In this embodiment, the data size of the control data is 4 bytes, and the data size of the numerical data is 1 byte. This numerical data is also used to determine whether the control data is normal or abnormal. In the present embodiment, normal / abnormal control data is determined using numerical data having a data size smaller than that of the control data. For this reason, the storage capacity required for storing the control data in the EEPROM 45 can be further reduced while ensuring the reliability of the control data.

  Here, the principle of control data normality / abnormality using numerical data will be described. As described above, numerical data that changes according to a predetermined rule every time the control data is written is generated as numerical data, and is stored in the EEPROM 45 together with the control data. On the other hand, the EEPROM 45 stores at least three sets of numerical data and storage data that become older in order from the latest. As a result of reading and comparing the at least three numerical data stored in the EEPROM 45, it is considered that the numerical data is correctly written in the EEPROM 45 when it is determined that the data has changed according to a predetermined rule.

  Since the control data forms a pair with the numerical data and is written into the EEPROM 45 at substantially the same time, if the numerical data is normally written, there is a possibility that the control data is also normally written into the EEPROM 45. high. For this reason, it is possible to determine whether or not the control data has been correctly written using the regularity of the numerical data.

  In this embodiment, the CPU 44 writes the control data and numerical data in the EEPROM 45 in this order. This is for avoiding a situation where the numerical data is normal but the control data is abnormal. In more detail, when writing numerical data and control data to the nonvolatile memory in this order, if the power is turned off while the control data is being written after the numerical data is written, the numerical data is written normally. May be written abnormally. In this case, although the numerical data changes according to a predetermined rule, an abnormality occurs in the control data. For this reason, in this embodiment, control data and numerical data are written in the EEPROM 45 in this order.

  Further, in the present embodiment, the EEPROM 45 stores the numerical data in the numerical value range “00 to FF” in all the storage areas for storing the numerical data before the CPU 44 writes the first set of numerical data and control data. The initial value “00” is written. Thus, even before at least three sets of numerical data and control data are written in the EEPROM 45, the CPU 44 reads the initial value “00” as numerical data, and determines whether or not the numerical data has changed according to a predetermined rule. Can be determined.

  Next, specific rules regarding numerical data in the present embodiment will be specifically described. The predetermined rule in this embodiment is to add “01” to the latest numerical data before update every time the control data is updated. Specifically, when the control data is updated for the first time, the updated numerical data becomes “01” by adding “01” to the initial value “00”. When the control data is updated for the second time, the updated numerical data becomes “02” by adding “01” to the latest numerical data “01” before the update.

  In the present embodiment, the CPU 44 writes the initial value “00” in the EEPROM 45 when the numerical data to be written next exceeds the limit value “FF” in the numerical value range “00 to FF”. Thereby, in “00 to FF”, the numerical data can be changed in accordance with a predetermined rule every time the control data is updated.

  In the present embodiment, when the numerical data exceeds the limit value “FF”, the initial value “00” is written in the EEPROM 45, so that at least three numerical data include the limit value “FF” and the initial value “00”. In this case, it is determined that the numerical data “00” and “FF” are changed according to a predetermined rule. Thus, the CPU 44 can compare the limit value “FF” with the initial value “00” and prevent erroneous determination that the initial value “00” has not changed according to a predetermined rule.

  Next, an example of writing data, which is a set of numerical data and control data, into the EEPROM 45 will be specifically described with reference to FIG. FIG. 3 is a diagram showing an address map of the EEPROM 45.

  As shown in the example of FIG. 3, for each type of control data, three storage areas for storing one set of numerical data and control data are allocated. For example, regarding the air conditioner switch on / off data, three storage areas of address 0, address 10, and address 20 are allocated. In these three storage areas, the order in which the latest set of numerical data and control data is written is predetermined. For example, for the air conditioner switch off / on data, each time the control data is updated, the latest set of numerical data and control data is written in the order of address 0, address 10, address 20, and address 0. In the example of FIG. 3, numerical data “01” and control data “DA1” are written at address 0, and this one set of data is the data of the last time. Further, numerical data “02” and control data “DA2” are written at the 10th address, and this one set of data is the previous data. Furthermore, numerical data “03” and control data “DA3” are written at the 20th address, and this set of data is the latest data. When the latest control data “DA3” is updated and the latest control data becomes “DA4”, the CPU 44 determines a predetermined rule (previous time) based on the latest data “03” in the stored numerical data. Numerical data “04” to be written next is generated. The CPU 44 overwrites and writes the latest set of numerical data “04” and control data “DA4” in the storage area at address 0 in the order of writing.

  Next, the data consistency check process using numerical data in this embodiment will be described in detail with reference to the flowcharts of FIGS. 4 and 5 and the explanatory diagram of FIG. FIG. 4 is a flowchart showing the first half of the data consistency check process, and FIG. 5 is a flowchart showing the second half of the data consistency check process. FIG. 6 is an explanatory diagram for explaining the mutual relationship between the numerical data and the control data.

  In the example shown in FIG. 6, the CPU 44 performs “numerical data N11 and control data D11”, “numerical data N12 and control data D12” in the order of arrows “I”, “B”, and “c” indicating the writing order. “Numeric data N13 and control data D13” are written in the EEPROM 45 every time the control data is updated. In the present embodiment, description will be made using an example in which three sets of numerical data and control data are stored in the EEPROM 45 as shown in FIG.

  First, in step S10 of FIG. 4, the CPU 44 reads stored data. Specifically, for example, as shown in FIG. 6, “numerical data N11 and control data D11”, “numerical data N12 and control data D12”, and “numerical data N13 and control data D13” are written in the EEPROM 45. The CPU 44 reads the three sets of numerical data and control data.

  In step S20, it is determined whether or not the numerical data N12 has changed from the numerical data N11 according to a predetermined rule according to the writing order “A”. If it is determined that the change has occurred according to the predetermined rule, the process proceeds to step S30. In step S30, it is determined whether or not the numerical data N13 has changed from the numerical data N12 according to a predetermined rule according to the writing order “B”. If it is determined that the change has occurred according to the predetermined rule, the process proceeds to step S40.

  In step S40, in the comparison between the numerical data N11 and the numerical data N12 and in the comparison between the numerical data N12 and the numerical data N13, it is determined that the values have changed according to predetermined rules. It is assumed that all the numerical data N11 to N13 and the control data D11 to D13 are written normally.

  Here, when two numerical data are sequentially selected from the three numerical data and the mutual comparison of the numerical data is performed, a total of three comparisons can be performed. And when all three numerical data are written correctly, the latest numerical data and the previous numerical data, and the comparison between the previous numerical data and the numerical data of the previous time, show changes according to a predetermined rule. Become. In this way, in the mutual comparison of the numerical data for a total of three times, when it is determined twice that the numerical data is changing according to a predetermined rule, all three numerical data are correctly written. Can be considered.

  For example, in the above case, as shown in FIG. 7, the numerical data is changed from “01 (N11)” to “02 (N12)” and further to “03 (N13)” according to the writing order “A” and “B”. It corresponds to the case where it has changed. In this case, since the three numerical data changes according to a predetermined rule, the latest numerical data can be specified from the three numerical data. Specifically, in the comparison between the numerical data N11 and the numerical data N12 and in the comparison between the numerical data N12 and the numerical data N13, it is determined that the values change according to predetermined rules. As shown in FIG. 7, numerical data “03 (N13)” is specified as the latest numerical data.

  The control data “D13” corresponding to the latest numerical data “03 (N13)” becomes the latest control data, and the air conditioner ECU 40 controls the automatic air conditioner using the latest control data “D13”. Thus, the air conditioner ECU 40 can perform control based on the most recently updated control data.

  On the other hand, if it is determined in step S30 that the numerical data has not changed according to a predetermined rule, the process proceeds to step S50. In step S50, it is determined whether or not the numerical data N11 has changed from the numerical data N13 according to a predetermined rule in accordance with the writing order “c”. If it is determined that the change has occurred according to the predetermined rule, the process proceeds to step S60.

  Also in step S60, since it is determined twice that the numerical data is changed according to a predetermined rule, it is considered that all three sets of numerical data N11 to N13 and control data D11 to D13 are written normally. It is.

  However, in the comparison between the numerical data N11 and the numerical data N12 and in the comparison between the numerical data N13 and the numerical data N11, it is determined that the values have changed according to predetermined rules. Thus, the numerical data “05 (N12)” is specified as the latest numerical data. As a result, the latest control data is also the control data “D12” corresponding to the latest numerical data “05 (N12)”.

  If it is determined in step S50 that the numerical data N13 and N11 have not changed according to a predetermined rule, the process proceeds to step S70. In step S70, in the comparison of the numerical data three times, it is determined that the change has occurred according to a predetermined rule only once, so writing of one set of numerical data and control data is abnormal, but two sets The writing of numerical data and control data is considered normal.

  Of the three numerical data, if the writing of one numerical data is abnormal, the numerical data is compared with the other two numerical data, respectively. The determination that the change is different from the rule is made twice. In other words, if writing of one numerical data out of three numerical data is abnormal, it is determined only once that it has changed according to a predetermined rule.

  However, in this case, it is considered that two numerical data among the three numerical data are normally written, so that the latest numerical data in the two numerical data can be specified. For example, as shown in FIG. 9, when it is determined that the change is made according to a predetermined rule only in the comparison between the numerical data N11 and N12 in the writing order “I”, the numerical data N11 and N12 are It can be determined that the data has been written normally and the numerical data N12 is newer. Therefore, in step S70, the numerical data N12 is specified as the latest numerical data, and the control data D12 corresponding to the latest numerical data N12 is set as the latest control data.

  As described above, by using at least three numerical data, even if an abnormality occurs in one numerical data, it is possible to select the latest control data from the stored control data. In this case, the selected control data is the actual latest control data or the latest previous control data depending on the data in which an abnormality has occurred.

  On the other hand, if it is determined in step S20 that the numerical data N11 and N12 have not changed according to a predetermined rule, the process proceeds to step S80. In step S80, the numerical data N12 is compared with the numerical data N13 according to the writing order “B”. At this time, if it is determined that the change has occurred according to a predetermined rule, the process proceeds to step S90. In step S90, the numerical data N13 and the numerical data N11 are compared according to the writing order “c”. Also in this determination, when it is determined that the change has occurred according to a predetermined rule, the process proceeds to step S100.

  In step S100, it is recognized that the writing of the three sets of numerical data N11 to N13 and the control data D11 to D13 is normal, the latest numerical data is identified as “N11”, and the control corresponding to the latest numerical data “N11” is performed. Data “D11” is the latest control data.

  That is, in the above-described case, for example, as shown in FIG. 10, the numerical data is “08 (N12)”, “09 (N13)”, “10 (N11)” according to the writing order “B” and “C”. Therefore, the latest numerical data can be specified as the numerical data “10 (N11)”.

  If it is determined in step S90 that the numerical data N13 and N11 are not changed according to a predetermined rule, the process proceeds to step S110. In this case, for example, as shown in FIG. 11, according to the writing order “b”, only the numerical data “08 (N12)” and the numerical data “09 (N13)” are changing according to a predetermined rule. Therefore, in step S110, the numerical data “09 (N13)” is regarded as the latest numerical data, and the control data “D13” corresponding to the latest numerical data “09 (N13)” is set as the latest control data.

  If it is determined in step S80 that the numerical data N12 and N13 are not changed according to a predetermined rule, the process proceeds to step S120. In step S120, the numerical data N13 and N11 are compared. In this determination process, when it is determined that the numerical data N13 and N11 are changing according to a predetermined rule, the process proceeds to step S130.

  In this case, for example, as shown in FIG. 12, according to the writing order “c”, only the numerical data “09 (N13)” and the numerical data “10 (N11)” are changing according to a predetermined rule. Therefore, in step S130, the numerical data “10 (N11)” is regarded as the latest numerical data, and the control data “D11” corresponding to the latest numerical data “10 (N11)” is set as the latest control data.

  If it is determined in step S120 that the numerical data N13 and N11 are not changed according to a predetermined rule, the process proceeds to step S140. In this case, for example, as shown in FIG. 13, it is a situation in which it is not determined that the data has changed once according to a predetermined rule in the mutual comparison of the numerical data for a total of three times.

  Thus, it is a situation where abnormality has occurred in at least two numerical data that the determination that the numerical data has changed in accordance with a predetermined rule is not made once in a total of three mutual comparisons. In this case, since it cannot be specified which numerical data is normal, it is considered that writing of the three sets of numerical data and stored data is abnormal. For this reason, in step S140, the air conditioner ECU 40 controls the automatic air conditioner using initial control data (default data) stored in advance in a ROM (not shown).

  As described above, according to the present embodiment, when updating the control data, the updated control data and the numerical data changed according to a predetermined rule are used as a set, and one set of numerical data and control data is stored in the EEPROM 45. Write to one storage area. The EEPROM 45 holds at least three sets of numerical data and control data that become older from the latest. Thereby, the required storage capacity can be reduced while ensuring the reliability of the control data.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, an example in which one set of numerical data and control data is written in one storage area has been described. However, when the data size of one set of numerical data and control data is larger than the storage capacity of one storage area, the respective data may be written in different storage areas. For example, the CPU 44 may write control data in the storage area at address 0 and write numerical data in the storage area at address 1.

  In the above-described embodiment, the example in which the numerical data increases by 1 has been described as the predetermined rule. However, the numerical change range may be other than 1, and the numerical data decreases instead of increasing. It may be a thing.

It is a block diagram which shows schematic structure of the automatic air-conditioner control apparatus 100 by this embodiment. It is a block diagram which shows the structure of air-conditioner ECU40 by this embodiment. It is explanatory drawing for demonstrating the address map of EEPROM45 in this embodiment. It is a flowchart which shows the first half part of the stored data consistency check process in this embodiment. It is a flowchart which shows the second half part of the stored data consistency check process in this embodiment. It is explanatory drawing for demonstrating the mutual relationship of numerical data and control data in this embodiment. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 1st specific example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 2nd example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 3rd specific example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 4th example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 5th example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 6th specific example. It is explanatory drawing explaining the mutual relationship of numerical data and control data in this embodiment using a 7th example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Switch input circuit 20 ... Sensor input circuit 30 ... Panel display circuit 40 ... Air-conditioner ECU
41 ... Battery 42 ... Key switch 43 ... Constant voltage circuit 44 ... CPU
45… EEPROM
46 ... serial communication line 50 ... motor drive circuit 60 ... relay drive circuit 70 ... power transistor drive circuit for air volume adjustment

Claims (11)

Non-volatile memory that can electrically rewrite the memory contents,
Data storage means for writing predetermined storage data into the nonvolatile memory;
A data storage device configured to retain the stored data even when the power is turned off,
The data writing means has numerical data generating means for generating numerical data that changes in accordance with a predetermined rule every time the stored data is written in a predetermined numerical range, and the numerical data and the stored data are paired. Writing to the non-volatile memory,
The non-volatile memory has an area for storing at least three sets of numerical data and storage data, and
At least three sets of numerical data and stored data stored in the nonvolatile memory are read out, and the numerical data in them are compared with each other to determine whether or not the numerical data has changed according to the predetermined rule. A determination means,
When it is determined by the determining means that the numerical data is changing according to a predetermined rule, the latest numerical data in the numerical data is specified, and the storage data corresponding to the latest numerical data is the latest stored data. A data storage device. It has a control unit that controls in-vehicle equipment mounted on the vehicle,
The data storage device according to claim 1, wherein the storage data is control data used by the control unit to control the in-vehicle device.   The data storage device according to claim 1 or 2, wherein a data size of the numerical data is smaller than a data size of the storage data.   The data writing means has a latest one set in an area storing the oldest one set of numerical data and storage data so that the nonvolatile memory can store at least the latest three sets of numerical data and storage data. 4. The data storage device according to claim 1, wherein the numerical data and the storage data are overwritten.   5. The data storage device according to claim 1, wherein the data writing unit writes the storage data and the numerical data in the nonvolatile memory in this order.   In the nonvolatile memory, initial values in the numerical value range are written in all areas for storing the numerical data before the first set of numerical data and storage data is written by the data writing means. The data storage device according to claim 1, wherein the data storage device is a data storage device.   The data storage device according to claim 6, wherein the data writing unit writes the initial value into the nonvolatile memory when the numerical data to be written next exceeds a limit value in the predetermined numerical range.   8. The data storage according to claim 7, wherein when the numerical data includes the limit value and the initial value, the determination means determines that the numerical data is changing according to the predetermined rule. apparatus. The determination means performs a mutual comparison of the numerical data three times in total by sequentially selecting and comparing the two numerical data from the three numerical data.
In this total of three comparisons, when it is determined twice that the numerical data has changed according to a predetermined rule, the three sets of numerical data and stored data are regarded as normal, and the 3 9. The latest numerical data is specified from the set of numerical data and stored data, and the stored data corresponding to the latest numerical data is used as the latest stored data. The data storage device described in 1.   In a total of three intercomparisons, when it is determined that the numerical data has changed according to a predetermined rule once, writing of one set of numerical data and stored data is abnormal, but two sets of numerical data In addition, it is assumed that the writing of the stored data is normal, and the latest numerical data is specified from the two sets of numerical data and stored data, and the stored data corresponding to the latest numerical data is the latest stored data. The data storage device according to claim 9.   In a total of three comparisons, when it is determined that the numerical data has not changed in accordance with a predetermined rule three times, the writing of the three sets of numerical data and stored data is regarded as abnormal, and is determined in advance. 10. The data storage device according to claim 9, wherein the default data is the latest storage data.

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