JP2012236451A - Program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a program capable of reducing nonvolatile memory more than a conventional method and of lessening a processing load and processing time during memory processing when storing information stored in the nonvolatile memory of an electronic control device in a vehicle.SOLUTION: A control program 23 is a program which is loaded in a RAM 21 to control an on-vehicle device 3 of vehicle 1. A stored program 24 is a program which transfers various data by control program execution on the RAM 21 as stored data 25 when turning a vehicle 1 to ignition off, and restores the stored data 25 to be returned to the RAM 21 to a nonvolatile memory 22 when turning the same to ignition on. The stored program 24 stores a state of a stack 231 in the control program 23 and values such as various set value functions 232a in the nonvolatile memory 22 at the minimum bit number.

Description

  The present invention relates to a program.

  In an electronic control unit (ECU) of a vehicle, when ignition is turned off, vehicle information such as user settings and specifications on a volatile memory is stored in a nonvolatile memory, and when an ignition is turned on again, the vehicle information is stored in a nonvolatile memory. The vehicle information in the volatile memory is returned to the volatile memory. For example, Patent Document 1 below discloses a technique for transferring vehicle information from a volatile memory to a nonvolatile memory in a short time.

JP 2006-193017 A

  Embedded software such as in-vehicle has a severe memory capacity limitation, and the amount of data that can be stored in a nonvolatile memory is limited. In the case of an electronic control device for a vehicle, since the nonvolatile memory is mounted separately from the normal memory, it is not easy to change to a nonvolatile memory having a larger capacity due to cost limitations.

  Therefore, it is necessary to compress the data to be stored. For example, JPEG which is an image compression technique and zip which is a file compression technique are known as techniques for compressing data. However, the processing load and the required ROM size are large, and it is not suitable for use in in-vehicle software. In addition, JPEG and zip also have a drawback of compressing even data that does not need to be compressed.

  For in-vehicle software, for example, the introduction of object orientation is considered as a technique for increasing functions and variations and improving the reusability of software. In that case, the amount of data to be stored will increase in the future. Therefore, in-vehicle software including object-oriented software, it is necessary to develop a technique for effectively compressing data stored in a nonvolatile memory. In Patent Document 1, only information movement from the volatile memory to the non-volatile memory at the time of vehicle failure is dealt with, and it is out of scope except at the time of vehicle failure.

  In view of the above-mentioned items, the problem to be solved by the present invention is that the information stored in the volatile memory of the vehicle electronic control device is more nonvolatile than the storage technique in the prior art. An object of the present invention is to provide a program capable of reducing the memory capacity and reducing the processing load and processing time of storage processing.

  In order to achieve the above object, a program according to the present invention is provided for each of a plurality of pieces of data indicating a control state of an in-vehicle device of a vehicle stored in a volatile memory included in an electronic control device installed in the vehicle. Assigning different binary numbers, the number of bits of the binary numbers being the minimum number of bits that can be assigned different binary values to all the data, and when stopping the drive unit of the vehicle, A storage step of storing the binary value obtained in the assigning step in a non-volatile memory provided is executed by a computer mounted on the vehicle.

  Thus, in the program according to the present invention, a different binary number is assigned to a plurality of data indicating the control state of the in-vehicle device stored in the volatile memory of the vehicle electronic control device with the minimum number of bits, and the vehicle drive unit The binary number is stored in the non-volatile memory when the operation is stopped. Therefore, instead of storing the object pointer as it is in the prior art or compressing the entire data by zip or the like, only the data that needs to be compressed among the data to be stored can be stored with the minimum number of bits. Therefore, the capacity of the nonvolatile memory can be reduced, and further, the processing load and processing time in the storage process can be reduced. In particular, in the case of in-vehicle devices, since the number of control states that can be taken is relatively small, the present invention is extremely effective for in-vehicle embedded software that can be compressed to a binary number with a small number of bits and has a severe memory capacity limitation. is there.

  Further, when starting the drive unit of the vehicle, the binary information stored in the nonvolatile memory is converted into data information indicating a control state of the in-vehicle device associated with the binary number, and the volatile The restoration step of restoring to the memory may be executed by a computer installed in the vehicle.

  According to the present invention, data stored as a binary number in the nonvolatile memory when the drive unit of the vehicle is stopped is restored as control information of the in-vehicle device in the volatile memory when the drive unit is started. Reading of a decimal number is sufficient, and the processing load and processing time in the restoration process can be reduced.

  Further, a calculation step for calculating the number of bits that can describe all the different binary values in accordance with the number of the data may be executed by a computer installed in the vehicle.

  According to the present invention, when assigning different binary numbers to a plurality of data stored in the volatile memory of the electronic control unit of the vehicle with the minimum number of bits, the minimum number of bits is automatically set according to the number of data. calculate. Therefore, it is not necessary to change the program even if various system configurations in the vehicle are changed, and a program that automatically and appropriately responds to the system change can be realized.

  The assigning step assigns a different binary number to each of a plurality of set values of the in-vehicle device of the vehicle stored in a volatile memory included in an electronic control device mounted on the vehicle, and the binary number The number of bits may include a set value assigning step in which a different binary value is assigned to all the set values to be stored in the nonvolatile memory.

  According to the present invention, not only the binary value of the minimum bit number is assigned to the data indicating the control state of the in-vehicle device when the driving unit of the vehicle is stopped, but also stored in the nonvolatile memory, the minimum bit is also set in the set value of the in-vehicle device. A binary number is assigned and stored in non-volatile memory. Therefore, information such as important control states and setting values that should be stored when the drive unit is stopped can be stored in the nonvolatile memory with the minimum number of bits, and the capacity of the nonvolatile memory, the storage processing load, and the processing time can be reduced. Reduction can be achieved.

  Further, the program may be written in an object-oriented programming language, and the data indicating the control state may be an object in the program.

  According to the present invention, in a program written in an object-oriented programming language, a binary number having a minimum number of bits is assigned to an object indicating the control state of an in-vehicle device, and the nonvolatile memory is stored when the driving unit of the vehicle is stopped. Remembered. Therefore, in the situation where object-oriented programs were introduced as in-vehicle software as a technology for increasing functions and variations and improving software reusability, object pointers were stored as they were in the conventional technology, or the entire data Is not compressed with zip or the like, but only the data that needs to be compressed among the data to be stored is stored with the minimum number of bits. Therefore, the capacity of the nonvolatile memory can be reduced, and further, the processing load and processing time in the storage process can be reduced. In particular, in the case of in-vehicle devices, since the number of control states that can be taken is relatively small, the present invention is extremely effective for in-vehicle embedded software that can be compressed to a binary number with a small number of bits and has a severe memory capacity limitation. is there.

  The information amount of the binary value may be smaller than the information amount of the object pointer.

  According to the present invention, since the information amount of the binary value is made smaller than the information amount of the object pointer, when storing a plurality of objects stored in the volatile memory of the electronic control unit of the vehicle, The binary information having an information amount smaller than the information amount of the object pointer is stored. Therefore, the capacity can be reduced in the nonvolatile memory as compared with the case where the object pointer is stored as it is as in the prior art, and further, the processing load and processing time in the storage processing can be reduced.

The block diagram in one Example of the storage control system of this invention. The figure which shows the example of a vehicle-mounted apparatus. The figure which shows an example of the state of a stack. The flowchart which shows the 1st example of map creation processing. The flowchart which shows the 2nd example of map creation processing. The flowchart which shows the 1st example of the memory | storage process to a non-volatile memory. The flowchart which shows the 1st example of the decompression | restoration process from a non-volatile memory. The flowchart which shows the 2nd example of the memory | storage process to a non-volatile memory. The flowchart which shows the 2nd example of the restoration process from a non-volatile memory. The figure which shows the 1st example of allocation of an index | exponent. The figure which shows the 2nd example of allocation of an index | exponent. The figure which shows the 3rd example of allocation of an index | exponent. The figure which shows the 1st example of preserve | saved data. The figure which shows the 2nd example of preserve | saved data. The figure which shows the example of the preservation | save data in a prior art.

  Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a schematic diagram of an apparatus configuration of a storage control system according to the present invention.

  The storage control system according to the present invention includes an ECU 2 and a vehicle-mounted device 3 controlled by the ECU 2 in a vehicle 2. The vehicle 2 includes an ignition switch 4 and a drive unit 40. The drive part 40 consists of an engine, an electric motor, etc., for example, and drives a wheel for advancing of a vehicle. When the user turns on the ignition switch 4, the drive unit 40 is started.

  The ECU 2 has the same structure as a normal computer and includes a CPU 20, a RAM 21, and a nonvolatile memory 22. The CPU 20 performs information processing related to the control of the in-vehicle device 3, and the RAM 21 is a volatile storage unit (memory) that functions as a work area of the CPU 20. The nonvolatile memory 22 is a nonvolatile storage unit such as an EEPROM, and stores various data and programs related to the control of the in-vehicle device 3.

  The nonvolatile memory 22 stores (saves and stores) a control program 23, a save program 24, and save data 25. The control program 23 is a program that controls the in-vehicle device 3. The storage program 24 is a program that manages processing for storing, in the nonvolatile memory 22, information related to the control of the in-vehicle device 3 stored in the RAM 21 (a part of the information). The control program 23 and the storage program 24 may be loaded into the RAM 21 and automatically executed by the CPU 20. The stored data 25 is data (information) transferred from the RAM 21 to the nonvolatile memory 22 by executing the storage program 24 (details will be described later).

  The control program 23 is a program described in an object-oriented program language (for example, Java (registered trademark), C ++, etc.). Therefore, the control program 23 includes (a plurality of) objects 230a, 230b, 230c,. Specifically, each of the objects 230a, 230b, 230c, and the like may be expressed in a program such as a component of the in-vehicle device 3 (described later), the in-vehicle device 3 itself, and its function (or control state).

  The control program 23 includes, for example, a stack 231 and set value functions 232a and 232b. The stack 231 stores, for example, a history of operations (functions, control states) in specific components in the in-vehicle device 3. The set value functions 232a, 232b, etc. are functions in the program (for example, member functions defined by the class to which the object belongs) representing various set values in the in-vehicle device 3.

  An example of the stack 231 is shown in FIG. In the example of the figure, the objects 230a to 230f are function A, function B, function C, function D, function E, and function F in the in-vehicle air conditioner. Specifically, the function A and the like may be an auto function, for example.

  In the stack 231, the function selected from the user among the function A, function B, function C, function D, function E, and function F by the FILO (First In Last Out) mechanism is illustrated as the earlier in time. By storing in the lower side, for example, the temporal transition of the control state of the in-vehicle air conditioner is stored. In the example of FIG. 3, the user sequentially selects function A, function D, and function C, and the history is stored in the stack 231.

  Returning to FIG. 1, the in-vehicle device 3 is various devices equipped in the vehicle 2. One specific example of the in-vehicle device 3 is the in-vehicle air conditioner 3a shown in FIG. The in-vehicle air conditioner 3 a controls the air conditioning in the passenger compartment of the vehicle 2. The in-vehicle air conditioner 3a has a partial component (component). Examples of the components 30, 31, 32, and the like include a temperature setting unit 33 for setting a desired in-vehicle temperature, a suction port 34 for switching between inside and outside air, and the like. The above configuration is connected by in-vehicle communication and can exchange information.

  With the configuration of FIG. 1, the storage control system compresses predetermined vehicle information from the RAM 21 (volatile memory) to the nonvolatile memory 22 and moves it as saved data 25 when the vehicle 1 is turned off. When the ignition is turned on again, the saved data 25 is restored to the RAM 21 and returned. The storage program 24 executes the above storage and restoration processes. Examples of processing procedures by the storage program 24 are shown in FIGS.

  First, FIG. 4 shows an example of a processing procedure for creating a map. Here, the map is information (collection) required for storing vehicle information in the nonvolatile memory 22 and restoring vehicle information from the nonvolatile memory 22. Specifically, for example, the size of the stack 231, the number of objects using the stack 231, the number (or index) assigned to each object using the stack 231, the storage start location in the nonvolatile memory 22 (start byte position and its number) The start bit position in).

  In the process of FIG. 4, first, in S10, a set of information to be stored in the nonvolatile memory 22 is designated. Here, the set of information may be vehicle information or information on the in-vehicle device 3. In the example of FIG. 1, for example, the state of the stack 231 is one set of information, and the numerical values of the setting value functions 232a and 232b are another set of information. Note that one set of information is not limited to information having a plurality of information, but includes information having only one information.

  Next, the storage start location in the nonvolatile memory 22 is designated in S20. Specifically, the storage start location may be a start byte position and a start bit position in the start byte position.

  Next, an index (number) is assigned to a plurality of information stored in S30. Examples thereof are shown in FIGS. In the example of FIG. 10, indices 1 to 6 are assigned to functions A to F that may be stored in the stack 231. In the example of FIG. 11, indexes 1 to 17 are assigned from 16 degrees to 32 degrees Celsius at the set temperature as the set value function 232 a. In the example of FIG. 12, in the suction port state as the set value function 232b, indices 1 to 3 are assigned to the inside air, the outside air, and the semi-inside air, respectively.

  Returning to FIG. 4, next, the number of bits for binarizing the exponent is designated in S40. Then, the exponent of each information stored in S50 is binarized (or converted into a binary number). At this time, the binary number having the number of bits designated in S40 is used.

  In the example of FIG. 10, the indices 1 to 6 of the function A to the function F can be expressed by 3-bit binary numbers, and are thus converted into binary numbers of 001 to 110. In the example of FIG. 11, indexes 1 to 17 from 16 degrees to 32 degrees Celsius can be expressed by 5-bit binary numbers, and are converted to binary numbers from 00001 to 10001. In the example of FIG. 12, the exponents 1 to 3 of the inside air, the outside air, and the semi-inside air can be expressed by 2-bit binary numbers, and are thus converted into binary numbers from 01 to 11.

  The above is the processing procedure of FIG. In the processing of FIG. 4, an exponent is assigned to each set of information, and the number of bits (the number of stored bits) in the binary representation of the exponent is determined. Accordingly, as in the examples of FIGS. 10 to 12, for example, the number of storage bits is 3 for the stack state, the storage bit number is 5 for the set temperature, and the storage bit number is 2 for the inlet state. Is set.

  Note that the examples in FIGS. 10 to 12 are examples in which indexes are assigned to all data, but the present invention is not limited to this. For example, the degree of importance is low and the necessity of storing in the nonvolatile memory 22 is low (not stored) ) Data does not have to be assigned an index.

  Next, the processing procedure in FIG. 5 is obtained by replacing S40 in FIG. 4 with the procedure from S41 to S44. In FIG. 4, the number of bits in the binary representation of the exponent is specified on the program creating the storage program, but in FIG. 5, the minimum number of bits is calculated in the storage program. Only the parts different from FIG. 4 will be described below.

  Specifically, first, in step S41, the variable bitSize is set to 1. Then, in S42, it is determined whether or not the numerical value obtained by subtracting 1 from 2 to the power of bitSize is equal to or larger than the maximum value of the exponent (for example, 6 in the example of FIG. 10). If it is equal to or greater than the maximum value of the index (S42: YES), the process proceeds to S44, and if it is less than the maximum value of the index (S42: NO), the process proceeds to S43. When the process proceeds to S43, the value of the variable bitSize is incremented by 1, the process returns to S42 again, and the same procedure is repeated until S42 becomes YES. After proceeding to S44, the value of the variable bitSize at that time is set as the number of binary bits to be stored.

  The above is the processing procedure of FIG. In the case of FIG. 5, for example, even when the number of functions stored in the stack 231 is changed, the minimum number of stored bits is automatically calculated, so that it is possible to automatically and appropriately cope with a system change.

  Next, FIGS. 6 to 9 will be described. 6 and 8 show the procedure of the compression and storage process in the nonvolatile memory 22, and FIGS. 7 and 9 show the procedure of the restoration process from the nonvolatile memory 22. However, in FIGS. 6 and 7, the number of stored bits and the data storage position are numerical values fixed in the program, and in FIGS. 8 and 9, the number of stored bits and the data storage position are calculated at the time of compression. 6 and 7 may be combined with FIG. 4, and FIGS. 8 and 9 may be combined with FIG.

  First, FIG. 6 will be described. FIG. 6 shows a procedure of processing for storing predetermined information in the RAM 21 in the nonvolatile memory 22 when the ignition is turned off. The processing procedure of FIG. 6 may be automatically started when the ignition switch 4 is turned off.

  In the process of FIG. 6, first, the CPU 20 initializes stored data to 0 in S100. Next, in S110, the CPU 20 acquires information to be stored as the saved data 25 (the set of information described above). Next, in S120, the CPU 20 designates a storage start location in the nonvolatile memory 22 of the information acquired in S110. This may be determined in advance according to what information is stored.

  Next, in S130, the CPU 20 acquires one piece of data (original data) from the information. One original data is, for example, one function (function C or the like) stored in the stack 231 in the above example. The data before the following conversion is called original data.

  Next, in S140, the CPU 20 determines whether or not an index is assigned to the original data in S30 described above. If an index is assigned (S140: YES), the process proceeds to S150, and if an index is not assigned (S140: NO), the process proceeds to S160.

  After proceeding to S150, the CPU 20 converts the original data to be stored in the nonvolatile memory 22. Specifically, the index assigned to the original data is converted data (hereinafter referred to as converted data). In S170, the CPU 20 compresses the converted data into a binary number having a storage bit size. The binary number acquired in this process may be the binary number determined in S50 described above.

  On the other hand, when the process proceeds to S160, the CPU 20 ignores the data to which no index is assigned and determines whether or not to pack the next data. When the next data is packed (S160: YES), the process proceeds to S210 without performing any operation on the converted data. When the next data is not packed (S160: NO), the process proceeds to S180 and the converted data is set to zero. When S180 ends, the process proceeds to S190.

  In S190, the CPU 20 shifts the stored data to the left by the storage bit size. In step S200, a binary number in which the converted data is compressed is substituted into a bit vacated on the right side as a result of the shift. In S210, the CPU 20 determines whether there is still uncompressed data. If there is still uncompressed data (S210: YES), the process returns to S130 and the above procedure is repeated. If there is no uncompressed data (S210: NO), the process proceeds to S220.

  In S <b> 220, the CPU 20 stores the saved data 25 created in the RAM 21 by the above processing in the nonvolatile memory 22. Next, in S230, the CPU 20 determines whether there is still uncompressed information (the above-mentioned set of information). If there is still uncompressed information (S230: YES), the process returns to S100 and the above procedure is repeated. If there is no more uncompressed information (S230: NO), the process of FIG. 6 is terminated.

  In the processing of FIG. 6 described above, an engineer (programmer) describes the set storage bit size in the storage program 24 in advance, and a binary number is designated for each data accordingly, and this is stored in the nonvolatile memory. 22 is stored. Therefore, the storage bit size is set in advance, and the process is relatively simplified. In this case, the storage program 24 may be created by combining FIGS. 4 and 6 (and FIG. 7).

  Next, FIG. 7 will be described. FIG. 7 shows a procedure of processing for restoring the stored data 25 in the nonvolatile memory 22 and returning it to the RAM 21 when the ignition is turned on again. The process in FIG. 7 may be automatically started when the ignition switch 4 is turned on.

  In the process of FIG. 7, first, in S300, the CPU 20 designates information to be restored (the above-mentioned set of information) in the saved data 25. Next, in S310, the CPU 20 acquires information on the storage start location (start byte position and start bit position in the storage data 25) of the information specified in S20.

  Next, in S320, the CPU 20 acquires a binary number corresponding to the storage bit size from the position acquired in S310. In S330, the CPU 20 determines whether or not an exponent is allocated to the acquired binary number. If an index is allocated (S330: YES), the process proceeds to S340, and if an index is not allocated (S330: NO), the process proceeds to S350.

  After proceeding to S340, the CPU 20 restores the original data from the acquired data index. Specifically, for example, data (original data) is restored from the relationship between data and binary numbers as shown in FIGS. When the process proceeds to S350, the CPU 20 sets the original data to 0. Subsequently, in S360, the CPU 20 returns the original data to the RAM 21.

  In S370, the CPU 20 determines whether there is still a binary number corresponding to the storage bit size that has not been restored among the data to be restored. If there is still binary data that has not been restored (S370: YES), the process returns to S320 and the above process is repeated. If there is no binary data that has not been restored (S370: NO), the process proceeds to S390.

  After proceeding to S390, the CPU 20 determines whether there is still unrestored information (the above-mentioned set of information) in the stored data 25 in the nonvolatile memory 22. If there is still information that has not been restored (S390: YES), the process returns to S300 and the above process is repeated. If all the saved data 25 has been restored (S390: NO), the processing in FIG. 7 ends.

  The above is the processing procedure of FIG. In the processing of FIG. 7, an engineer (programmer) describes the set storage bit size in advance in the storage program 24, and each data stored as a binary number in the nonvolatile memory 22 is restored to the RAM 21 accordingly. The Therefore, the storage bit size is set in advance, and the process is relatively simplified.

  Next, FIG. 8 will be described. FIG. 8 shows the procedure of compression storage processing in the nonvolatile memory 22 of the type for calculating the number of storage bits and the data storage position at the time of compression. The processing procedure of FIG. 8 is obtained by adding S125, S211 and S212 to the processing procedure of FIG. Hereinafter, parts different from FIG. 6 will be described.

  In S125 of FIG. 8, the CPU 20 calculates the storage bit size from the maximum value (maximum number) of the exponent. This calculation process may be executed according to FIG. 5 (S41 to S44).

  In S211 and S212 of FIG. 8, between different types of information in the stored data (in the example of FIG. 1, for example, the stack 231, the set value function 232a, and the set value function 232b are different types of information) A process for inserting bit data of an indicia indicating the presence is executed. In short, the storage program 24 includes an insertion step of inserting bit data indicating that there is a gap between one set of the plurality of objects and another set of the plurality of objects in the information stored in the nonvolatile memory. Specifically, first, in S211, the CPU 20 shifts the stored data to the left by the bit size of the mark. Next, in S212, the CPU 20 substitutes the bit data of the sign into the bit left on the right side by the left shift. Specifically, the sign bit data may be set to, for example, a maximum value in the number of digits of the bit size or zero in the number of digits of the bit size.

  The above is the change from FIG. 6 in FIG. In the process of FIG. 8, when storing the saved data 25 in the nonvolatile memory 22, the number of stored bits is calculated for each stored information (a set of information) and the binary number of the stored bits is stored. At the same time, a mark is stored between one set of information in the stored data 25 and another set of information to clarify the delimiter of the information. Therefore, even if various system changes are made in the vehicle 1, it is not necessary to rewrite the storage program 24, and the optimum number of stored bits is automatically calculated in response to the system change flexibly.

  Next, FIG. 9 will be described. FIG. 9 shows the procedure of the restoration process from the nonvolatile memory 22 to the RAM 21 of the type for calculating the number of storage bits and the data storage position at the time of compression. The processing procedure of FIG. 9 is obtained by adding S315 in the processing procedure of FIG. 7 and changing S370 to S325. Hereinafter, parts different from FIG. 7 will be described.

  In S315 of FIG. 9, the CPU 20 calculates the storage bit size from the maximum value (maximum number) of the exponent. This calculation process may be executed according to FIG. 5 (S41 to S44).

  S325 in FIG. 9 is processed next to S320, and it is determined whether or not the acquired data is an indication. If the acquired data is a sign (S325: YES), the process proceeds to S390, and if the acquired data is not a sign (S325: NO), the process proceeds to S330.

  As described above, in the process of FIG. 9, the storage bit size information of the stored information is not used, but when the indicia is acquired as a delimiter between different pieces of information, it is recognized that the restoration of one information is completed. To do. Therefore, as in FIG. 8, it is not necessary to rewrite the storage program 24 even if various system changes are made in the vehicle 1, and the optimum number of storage bits is automatically calculated in response to the system change flexibly, and accordingly A restoration process is executed. In the above case, the storage program 24 may be created by combining FIG. 5, FIG. 8, and FIG.

  FIG. 14 shows an example of saved data 25 in which the stack of FIG. 3 is saved using the binary representation of FIG. Since the storage states of the stack 231 in FIG. 3 are function A, function D, function C, and empty in order, as shown in FIG. 12, “001”, “100”, “011”, “000” are sequentially displayed. Remember. In the example of FIG. 12, the sky is set to “000”, but it may be other than the binary number shown in FIG.

  FIG. 15 shows an example of saved data 25 in the case of the stack of FIG. 3 in the prior art. In the prior art, when storing the stack 231 of FIG. 3, the pointers of the functions A, D, and C (variables indicating the addresses in the object memory in the object-oriented programming language) are stored data. Is 4 bytes of information, and as shown in FIG. 15, a total of 16 bytes are required to store the stack state of FIG. On the other hand, in the example of FIG. 14 of the present invention, only a total of 12 bits are used for storing the state of the stack of FIG. 3, and the information amount is about 1/10. Therefore, it is possible to reduce the capacity of the nonvolatile memory 22 and to reduce the processing load and processing time of the storage process.

  The stored data 25 may be as shown in FIG. 13 instead of FIG. In the example of FIG. 13, the indices of function A, function D, function C, and empty stored in the stack 231 are stored in order in the saved data 25 (note that the empty index is 0 here). Normally, an integer value that is an exponent is 1 byte of information, so a total of 4 bytes are used in the example of FIG. Therefore, the amount of information can be reduced to a quarter of that of the prior art of FIG. 15, and the capacity of the nonvolatile memory 22 can be reduced. (Also in comparison with FIG. 13, the amount of information stored in the nonvolatile memory 22 is reduced in FIG. 14. That is, the binary information amount in FIG. 14 is the index (integer value) assigned to the object. (In this case, the binary information amount is smaller than the integer information number assigned to the object.)

  According to the inventor's knowledge, the maximum number of the above-mentioned indexes is almost 7 or less, 8 to 15 is not 10%, and 16 to 30 is hardly found for various on-vehicle devices 3. In terms of the number of stored bits, most are 3 bits, 4 bits are not 10%, and 5 bits are almost none. Therefore, a good compression ratio can be achieved when the binary number having the minimum number of bits is compressed by the method of the present invention.

  In the above embodiment, the control program 23 and the storage program 24 are programs described in an object-oriented programming language, but the present invention is not limited to such an embodiment. In the present invention, a different binary number is assigned to each of a plurality of data indicating the control state of the in-vehicle device of the vehicle, which is stored in a volatile memory included in the electronic control device installed in the vehicle, and the binary number The number of bits is determined by the assignment step in the assignment step to set the minimum number of bits to which different binary values can be assigned to all data, and the assignment step in the nonvolatile memory provided in the vehicle when the vehicle drive unit is stopped. A storage step of storing a decimal value is executed by a computer installed in the vehicle.

  Naturally, even if it is not an object-oriented programming language, the binary expression corresponding to the set temperature and the suction port state shown in FIGS. 11 and 12 may be stored in the nonvolatile memory 22 when the ignition is turned off. Further, even when each function shown in FIG. 10 is not described as an object in the program, when storing the state of the stack 231 when the ignition is turned off, the binary number representation of each function in the stack is nonvolatile as described above. May be stored in the memory 22.

1 Vehicle 2 ECU (Electronic Control Device)
3 On-vehicle equipment (on-vehicle equipment)
21 RAM (volatile memory)
22 Nonvolatile memory 23 Control program 24 Saved program 25 Saved data

Claims (6)

A different binary number is assigned to each of a plurality of data stored in a volatile memory of an electronic control device installed in the vehicle and indicating the control state of the in-vehicle device of the vehicle, and the number of bits of the binary number is Assigning a minimum number of bits that can be assigned a different binary value to all the data to be stored in the non-volatile memory;
A storage step of storing the binary value obtained in the assigning step in a non-volatile memory provided in the vehicle when the driving unit of the vehicle is stopped;
Is executed by a computer installed in the vehicle.   When starting the drive unit of the vehicle, the information on the binary number stored in the nonvolatile memory is converted into data information indicating the control state of the in-vehicle device associated with the binary number, and the volatile The program according to claim 1, which causes a computer installed in a vehicle to execute a restoration step of restoring to a memory.   The program according to claim 1 or 2, which causes a computer mounted on a vehicle to execute a calculation step of calculating the number of bits that can describe all the different binary values in accordance with the number of data.   The assigning step assigns a different binary number to each of a plurality of set values of the in-vehicle device of the vehicle stored in a volatile memory included in an electronic control device installed in the vehicle, 4. The program according to claim 1, wherein the number of bits includes a setting value assigning step in which a different binary value is assigned to all the setting values to be stored in the nonvolatile memory. . A program written in an object-oriented programming language
The program according to any one of claims 1 to 4, wherein the data indicating the control state is an object in the program.   The program according to claim 5, wherein the information amount of the binary value is smaller than the information amount of the pointer of the object.

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