WO2013061396A1

WO2013061396A1 - Communication device, communication system and communication method

Info

Publication number: WO2013061396A1
Application number: PCT/JP2011/074442
Authority: WO
Inventors: 義和酒井
Original assignee: トヨタ自動車株式会社
Priority date: 2011-10-24
Filing date: 2011-10-24
Publication date: 2013-05-02

Abstract

Provided are a communication device capable of increasing, with regard to data communicated using the CAN protocol, reliability at a processing point for the data, a communication system provided with the communication device, and a communication method using the communication system. The present invention is a CAN controller which receives a communication message transferred between CAN controllers on the basis of the CAN protocol, such that object data is stored in an object data storage area defined within one frame as an area for storing the object data included in the communication message, and by receiving the communication message in which a checksum is stored which is used for detecting the presence or absence of modifications of the object data in an area different from the object data storage area within the same frame, from the same received communication message, the object data stored in the object data storage area is acquired together with the checksum which is stored in an area different from the object data storage area.

Description

COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

The present invention relates to a communication device connected to a vehicle network, a communication system including the communication device, and a communication method using the communication system.

As is well known, a plurality of electronic control units (ECUs) mounted on a vehicle are connected to each other via a network so that information (vehicle information) held by these electronic control units can be transmitted and received between each other. Often configured. One of communication systems that constitute such a vehicle network system is a control area network (CAN).

In the in-vehicle CAN, the maximum amount of data that can be transmitted in a frame as a unit in communication is set to 64 bits (8 bytes) at the maximum. For this reason, in a vehicle-mounted CAN, large data such as a program that cannot be stored in one frame is divided into a plurality of pieces, and each of the divided data is stored and transferred in different frames. However, the increase in the number of frames increases the information added to the frames in addition to the stored data, so-called overhead, so the increase in the amount of communication including the increase in overhead cannot be ignored.

Therefore, an example of a technique for suppressing an increase in communication volume is described in Patent Document 1.

In the system described in Patent Document 1, a plurality of control devices (ECUs) are connected to a communication line in a manner capable of mutual communication based on the CAN protocol. In addition, a diagnostic terminal capable of outputting large data such as a new control program to a specific ECU can be connected to the communication line by an operation of an operator or the like.

When transferring large data, this diagnostic terminal transfers to an extended ID area defined in an area different from the predetermined data area in addition to the predetermined data area specified in the CAN extended format. It is a specification that can store data to be stored. In addition to the predetermined data area, the specific ECU can acquire data transferred from an extended ID area or the like to reconstruct large data. Thus, according to this system, it is possible to transfer data having a maximum size of 1.39 times the size of the predetermined data area from the diagnosis terminal to the specific ECU.

JP 2010-258990 A

By the way, the above-mentioned CAN ensures the reliability of data to be transferred based on the protocol regulations. That is, in the system described in Patent Document 1, the reliability of data to be transferred is ensured based on the CAN protocol when this data is received from the network. On the other hand, the CAN protocol guarantees the reliability even if there is a possibility that the transferred data after reception, that is, the data after communication processing via the network, may be altered due to noise or the like. I can't. As described above, the data after the communication process (reception process) is not guaranteed to the reliability at the time when it is processed by the ECU.

Therefore, in recent years, an ECU that processes received data has further acquired check data such as a checksum for checking errors in all transferred data after reception of all data is completed. The ECU verifies the reliability of all the transferred data based on the check data, and then performs a predetermined process on the all data. As another method, in the system as described in Patent Document 1, the data to be checked is included in advance in the data to be transferred, and the ECU that has received this data extracts the data for checking from the data, There is also a method for verifying the reliability of the received data. In any case, if modification or the like is found in the data received by the ECU at the time of processing by the ECU, the received data cannot be used and is wasted. It tends to grow.

The present invention has been made in view of such a situation, and an object of the present invention is to improve the reliability of data communicated by the CAN protocol at the time of processing the data and the communication apparatus. And a communication method using the communication system.

Hereinafter, means for solving the above-mentioned problems and their effects will be described.

In order to achieve the above object, a communication device provided by the present invention is a communication device that receives a communication message transferred between communication devices based on a communication protocol applied to a control area network. The target data is stored in a target data storage area defined in one frame as a target data storage area, and the target data is modified in a different area from the target data storage area in the same frame. By receiving a communication message storing a check value used for detecting the presence or absence of the target data, the target data storage area together with the target data stored in the target data storage area from the received communication message The check values stored in a different area are also acquired.

In order to achieve the above object, a communication method provided by the present invention is a communication method for receiving a communication message transferred between communication devices based on a communication protocol applied to a control area network. The target data is stored in a target data storage area defined in one frame as a target data storage area, and the target data is modified in a different area from the target data storage area in the same frame. Receiving a communication message in which a check value used for detection of presence / absence is stored, obtaining a target data stored in the target data storage area from the received communication message, and receiving the same Before being stored in an area different from the target data storage area from the communication message And a step of obtaining a check value.

According to such a configuration or method, in a control area network, so-called CAN communication protocol, the receiving communication device detects the target data to be transferred between the communication devices and whether or not the target data has been altered. The check value to be obtained can be acquired from one communication message (one frame). In this way, since the target data and the check value transferred between the communication devices can be acquired from one communication message, the communication amount of the communication message in the network can be reduced as compared with the case where the check value is acquired as a separate communication message. Can be reduced. As a result, it is possible to reduce overhead generated for each communication message, arbitration during transmission, and the like. The target data storage area corresponds to a data field defined in the CAN protocol. The data field is an area where the user can freely define the contents (data), and the contents (data) defined by the user in the same area are the target data.

In addition, since the receiving communication device can acquire the target data and the check value from one communication message, the correspondence between the two communication messages required when the target data and the check value are sent in different communication messages. Management can be omitted. For this reason, detection of modification of the target data is simplified and convenience is improved. For example, when the device that processes the transferred target data acquires the target data to be transferred and waits for the check value to be sent, or when the check value cannot be received, the check value is resent. It becomes possible to omit the process of requesting.

As a preferred configuration, the communication message is configured as an extended format defined by a communication protocol applied to the control area network, and is an area different from the target data storage area in which the check value is stored. An extension ID area for storing an extension ID defined in the extension format is used.

According to such a configuration, the receiving communication device can use the check value added without changing the extended format. Actually, there are many communication devices that use only the basic ID and do not use the extended ID. In such a communication device that does not use the extended ID, the presence or absence of modification of the target data is detected only by using the extended ID area. A check value is easily added. It is also easy to change an existing device that supports the CAN protocol to such a communication device.

As a preferred configuration, message filtering for determining whether or not the communication message is necessary is performed based only on the basic ID included in the extended format.

According to such a configuration, the receiving communication device is prevented from affecting the message filtering by the check value added to the extension ID. As a result, the communication message to which the check value is added can be more suitably processed.

As a preferred configuration, whether or not to include the check value in the communication message can be selected, and when it is selected not to include the check value, it is stored in the extended ID area of the communication message. The extension ID is used for the message filtering together with the basic ID.

According to such a configuration, the receiving communication device can use the area for storing the extension ID as if the extension ID that is the original use is stored. Can be improved.

As a preferred configuration, there is provided a processing device that detects whether or not the target data has been modified based on a check value acquired together with the received target data.

According to such a configuration, the processing device can detect whether or not the target data acquired from the receiving communication device has been altered by the check value included in the same communication message. As described above, since the target data and the check value can be acquired from the same communication message, it is expected that the processing relating to the detection of the presence / absence of alteration is accelerated.

In order to achieve the above object, a communication device provided by the present invention is a communication device that transmits a communication message transferred between communication devices based on a communication protocol applied to a control area network, and includes the communication message. The target data is stored in a target data storage area defined in one frame as a target data storage area, and the target data is modified in a different area from the target data storage area in the same frame. A check value used for presence / absence detection is stored to generate the communication message to be transmitted.

In order to achieve the above object, a communication method provided by the present invention is a communication method for transmitting a communication message transferred between communication devices based on a communication protocol applied to a control area network, wherein the communication message is As a step prior to the step of transmitting, the step of storing the target data in a target data storage region defined in one frame as a region for storing the target data included in the communication message, and the target data in the same frame Storing a check value used for detecting whether or not the target data is altered in an area different from the storage area.

According to such a configuration or method, in a control area network, a so-called CAN communication protocol, a transmitting communication device detects target data to be transferred between communication devices and whether or not the target data has been altered. The check value to be stored can be stored in one communication message (one frame). As described above, if the target data and the check value transferred between the communication devices are stored in one communication message, the communication amount of the communication message in the network can be reduced as compared with the case where the check value is transmitted as a separate communication message. Can be reduced. As a result, it is possible to reduce overhead generated for each communication message, arbitration during transmission, and the like.

Further, since the transmitting communication device stores the target data and the check value to be transferred between the communication devices in one communication message, it is necessary when sending the target data and the check value in different communication messages. This makes it possible to omit the management of the correspondence between two communication messages, thereby improving convenience. For example, the device that transmits the target data may eliminate the waiting time until the check value is transmitted after transmitting the target data, or may omit processing corresponding to a retransmission request for one of the two. become able to.

As a preferred configuration, the communication message is configured as an extended format defined by a communication protocol applied to the control area network, and is an area different from the target data storage area for storing the check value, An extension ID area for storing an extension ID defined in the extension format is used.

According to such a configuration, the transmitting communication device can add the check value without changing the extended format. Actually, there are many communication devices that use only the basic ID and do not use the extended ID. In such a communication device that does not use the extended ID, the presence or absence of modification of the target data is detected only by using the extended ID area. A check value can be easily added. It is also easy to change an existing device that supports the CAN protocol to such a communication device.

As a preferred configuration, whether or not to store the check value in the extended ID area can be selected, and when it is selected not to store the check value, the check value is not stored in the extended ID area. .

According to such a configuration, the transmitting communication apparatus can store the extended ID that is originally intended for use in the area for storing the extended ID, thereby improving the versatility of the communication apparatus. become able to.

In order to achieve the above object, a communication system provided by the present invention is a communication system in which transmission and reception of a communication message transferred between communication devices based on a communication protocol applied to a control area network is performed. The communication device described above is used as a communication device that transmits a communication message, and the communication device described above is used as a communication device that receives the communication message.

In order to achieve the above object, a communication method provided by the present invention is configured to transmit and receive a communication message transferred between communication devices based on a communication protocol applied to a control area network by mutual communication between the communication devices. A communication method for performing communication using the communication method described above as a communication method for transmitting the communication message by a communication device for transmitting the communication message, wherein the communication device for receiving the communication message receives the communication message. As a method, the communication method described above is used, and the communication message transmitted from the communication device that transmits the communication message is acquired by the communication device that receives the communication message.

According to such a configuration or method, in a control area network, a so-called CAN communication protocol, the communication system detects the target data to be transferred between communication devices and the presence / absence of alteration of the target data. The value can be stored in one communication message (one frame). Then, the target data and the check value stored in the communication message can be acquired from the one communication message.

In this way, if the target data transferred between communication devices and the check value are stored and transmitted in one communication message, the check value is transmitted and received as a separate communication message. Thus, the communication volume of communication messages in the network can be reduced. As a result, the overhead generated for each communication message in the communication system, arbitration during transmission, and the like can be reduced.

In addition, since the communication system stores the target data and the check value in one communication message and transmits and receives them, the two communication messages required when the target data and the check value are transmitted in different communication messages. It becomes possible to omit the management of the correspondence relationship and the convenience is improved. For example, the device that transmits the target data and the device that receives the target data may be configured to eliminate the waiting time until the next check value is transmitted and received after the target data is transmitted and received. It becomes possible to omit the processing corresponding to the retransmission request. Thereby, a quick communication can be performed as a communication system.

As a preferred configuration, a communication system for transmitting and receiving communication messages transferred between communication devices based on a communication protocol applied to a control area network, wherein the communication device described above is used as a communication device for transmitting the communication messages. The communication device described above is used as a communication device that receives the communication message, and notifies the communication device that transmits the communication message whether to store the check value in the extended ID area. A function for transmitting a message is further provided, and the communication device that receives the communication message is provided in the extension ID area based on acquiring a message for notifying whether or not the check value is stored in the extension ID area. A function of recognizing whether or not the check value is included is further provided.

According to such a configuration, the communication device that receives the communication message is transmitted and received as a communication system because whether or not a check value is stored in the communication message is set by the communication device that transmits the communication message. It becomes easy to switch the setting of whether to store the check value in the communication message. Thereby, the applicability of such a communication system is enhanced.

As a preferred configuration, a communication system for transmitting and receiving communication messages transferred between communication devices based on a communication protocol applied to a control area network, wherein the communication device described above is used as a communication device for transmitting the communication messages. A communication device described above is used as a communication device that receives the communication message, and a message requesting storage of the check value in the extension ID is transmitted to the communication device that receives the communication message. A function for storing the check value in the extension ID area based on obtaining a message for requesting storage of the check value in the extension ID. Provide further.

According to such a configuration, the communication device that transmits the communication message is set by the communication device that receives the communication message to determine whether or not to store the check value in the communication message. It becomes easy to switch the setting of whether to store the check value in the message. Thereby, the applicability of such a communication system is enhanced.

The block diagram which shows the schematic structure about 1st Embodiment which actualized the communication system provided with the communication apparatus which concerns on this invention. The block diagram which shows schematic structure of the communication apparatus shown in FIG. FIG. 2 is a schematic diagram schematically showing a data frame of a CAN protocol used in the communication system shown in FIG. 1, wherein (a) is a schematic diagram showing a standard format, (b) is a schematic diagram showing an extended format, and (c). FIG. 4 is a schematic diagram showing how the extended format is used in this embodiment. The flowchart which shows the analysis procedure of the format in the communication apparatus shown in FIG. The flowchart which shows the procedure in which the arithmetic unit shown in FIG. 2 processes the analyzed data. The sequence diagram which shows the utilization aspect of the extended format of the CAN protocol about 2nd Embodiment which actualized the communication system provided with the communication apparatus which concerns on this invention with time. The sequence diagram which shows the utilization aspect of the extension format of the CAN protocol about other embodiment which actualized the communication system provided with the communication apparatus which concerns on this invention with time.

(First embodiment)
A first embodiment embodying a communication system including a communication apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the vehicle 1 includes a communication system as a vehicle network system. The communication system includes a first electronic control unit (ECU) 10, a second ECU 13, and a communication bus 16 that connects the first and

second ECUs

10 and 13 so that they can communicate with each other. As a result, the first ECU 10 and the second ECU 13 can exchange (transmit / receive) various information used for control with each other via the communication bus 16. The communication system is configured as a CAN network to which a CAN (Control Area Network) protocol is applied as a communication protocol.

Each of the first ECU 10 and the second ECU 13 is a control device that is used for various controls of the vehicle 1. For example, an ECU that controls a drive system, a traveling system, a vehicle body system, an information equipment system, or the like. It is. For example, an ECU for a drive system is an ECU for an engine, an ECU for a travel system is an ECU for a steering or a brake ECU, and an ECU for controlling a vehicle body system An ECU for a light and an ECU for a window can be mentioned, and an ECU for controlling an information device system includes an ECU for car navigation.

The first ECU 10 is provided with an information processing device 11 that performs processing required for various controls, and a CAN controller 12 as a communication device that can transmit and receive communication messages based on the CAN protocol. Yes. In the information processing apparatus 11, for example, the predetermined control function is provided by executing an application (application program) 111 that provides the predetermined control function.

Similarly, the second ECU 13 includes an information processing device 14 that performs processing required for various controls, and a CAN controller 15 as a communication device that can transmit and receive communication messages based on the CAN protocol. Is provided. In the information processing apparatus 14, for example, the predetermined control function is provided by executing an application (application program) 141 that provides the predetermined control function.

Also, the CAN controller 12 of the first ECU 10 and the CAN controller 15 of the second ECU 13 are connected to one communication bus 16, respectively. The communication bus 16 includes a communication line that can transmit a communication message based on the CAN protocol. Note that the communication bus 16 may include wireless communication as part of a communication path, or may include a path that passes through another network via a gateway or the like. Each of the CAN controllers 12 and 15 is configured to be able to transmit and receive a communication message based on a frame defined by the CAN protocol via the communication bus 16. In the CAN protocol, four types of frames such as a data frame (DF) and a remote frame (RF) are defined as a frame as a unit in communication.

Here, with reference to FIG. 3, a data frame which is one of CAN protocol communication messages will be described.

The data frame is a format used for transferring “target data” arbitrarily set by the user between the information processing device 11 of the first ECU 10 and the information processing device 14 of the second ECU 13. The “target data” arbitrarily set by the user is, for example, information on programs such as program parameters and application software for information processing devices, so-called repro data, information on vehicles such as vehicle parameters and vehicle speed, etc. This is data consisting of all or part of various information related to the execution of control. As the format of the data frame, “standard format F1” shown in FIG. 3A and “extended format F2” shown in FIG. 3B are defined. The “standard format F1” includes an 11-bit “basic ID area” for storing the “basic ID”, a “data length area (DLC)” for storing the “data length”, and “target data”. "Data area" having a maximum length of 64 bits is defined as a target data storage area for storing "." As in “standard format F1,” “extended format F2” defines “basic ID area”, “data length area”, and “data area”, and stores “extended ID”. A bit length “extended ID area” is defined.

In this way, it is specified that the “target data” to be transferred is stored in the “data area” in the data frame, regardless of whether it is “standard format F1” or “extended format F2”. Yes. This “data area” is configured such that the length of the area can be changed to an arbitrary number of bytes of 0 to 8 bytes (0 to 64 bit data). That is, the “data area” cannot store target data having a length exceeding 8 bytes (64 bits). However, some of the information that you want to transfer has data that exceeds 8 bytes, so long information with a length of 8 bytes or more is divided into 8 bytes each, Each message is forwarded to another communication message. In addition, the divided data transmitted by each different communication message are combined on the receiving side so as to be reconstructed into the original length data. It should be noted that dividing and transferring information having a long data length in this way cannot be avoided according to the data frame of the CAN protocol.

By the way, in this embodiment, as shown in FIG. 3C, although the “extended format F2” is used as the format of the data frame, the “extended ID area” of the same format is replaced with “extended ID” as a check value. The “special format F3” for storing the “checksum” is also available.

That is, the first ECU 10 and the second ECU 13 can transmit and receive various types of information necessary for their control by communication messages composed of data frames transmitted and received via the communication bus 16. Yes.

Next, the details of the first ECU 10 will be described with reference to FIG. The second ECU 13 has the same configuration as that of the first ECU 10, and therefore will not be described in detail. That is, the information processing device 14 of the second ECU 13 corresponds to the information processing device 11 of the first ECU 10, and the CAN controller 15 of the second ECU 13 corresponds to the CAN controller 12 of the first ECU 10.

The information processing device 11 of the first ECU 10 includes a microcomputer having an arithmetic device (CPU) and a storage device. In other words, the information processing apparatus 11 includes an arithmetic device that executes arithmetic processing of a control program (application), a read-only memory (ROM) that stores the control program (application), data, and the like, and arithmetic operations of the arithmetic device. Volatile memory (RAM) is provided in which results are temporarily stored. Accordingly, the information processing apparatus 11 reads the control program (application 111) held in the storage device into the arithmetic device and executes it, thereby providing the function of the application 111 to the control target and performing the control. Control the target. In the information processing apparatus 11, one or more pieces of information that the second ECU 13 has are used for the operation of the application 111.

The information processing apparatus 11 detects information transmitted / received to / from the second ECU 13, that is, the arbitrary data 112 consisting of all or part of the transferred information, and whether or not the contents of the arbitrary data 112 are altered. Therefore, a checksum 113 calculated by applying a predetermined algorithm to the arbitrary data 112 is provided. That is, when a plurality of communication messages are received, the information processing apparatus 11 acquires the arbitrary data 112 based on the “target data (M3)” of each received communication message, and the acquired plurality of arbitrary data 112 can be combined to reconstruct one piece of information. On the other hand, when trying to transmit a communication message, the information processing apparatus 11 divides one piece of information to be transferred into a plurality of pieces, generates each piece of arbitrary data 112 that is the divided piece of information, and sets each piece of arbitrary data 112 The communication message can be set as “target data (M3)”.

That is, when the first ECU 10 receives the communication message from the second ECU 13, the value of “target data (M3)” read from the communication message is set in the arbitrary data 112 of the information processing apparatus 11. In the checksum 113, the value of “checksum (M2)” read from the communication message is set. When the checksum is not included in the communication message, nothing is set in the checksum 113, for example, it is cleared to “0”.

In the first ECU 10, an algorithm for verification corresponding to the algorithm used by the second ECU 13 for calculating the checksum 113 is set. Thereby, the information processing apparatus 11 can detect whether the arbitrary data 112 has been modified based on the checksum 113 corresponding to the arbitrary data 112. Then, the information processing apparatus 11 uses the arbitrary data 112, which has been detected as a result of the detection, not to be modified for the execution of the application 111. In this case, since the presence / absence of alteration of the arbitrary data 112 is detected immediately before being used for the execution of the application 111, the reliability of the arbitrary data 112 is improved, and the reliability of the operation of the application 111 using the arbitrary data 112 is improved. Can also be enhanced.

On the other hand, when a communication message is transmitted from the first ECU 10 to the second ECU 13, a part of information transferred from the application 111 is written in the arbitrary data 112 of the information processing apparatus 11, and an application is written in the checksum 113. A checksum corresponding to the arbitrary data 112 transferred from 111 is written. At this time, the application 111 calculates a checksum 113 corresponding to the arbitrary data 112 based on applying a predetermined algorithm to the arbitrary data 112 so that the presence / absence of falsification of the arbitrary data 112 can be detected. Since the calculated checksum 113 is stored in the “extended ID area”, the length is calculated to be 18 bits or less. The second ECU 13 in which the algorithm for verification corresponding to the predetermined algorithm is set can detect whether or not the received arbitrary data 112 has been tampered with based on the received corresponding checksum 113.

The information processing device 11 of the first ECU 10 has a flag used to determine whether or not “checksum” is set in the communication message consisting of “extended format F2” when the information processing device 11 receives the communication message. The switch SW flag 114 is set. When the received communication message does not include “checksum”, the switch SW flag 114 is set to “0” (“off”) indicating that no checksum is added. On the other hand, when “checksum” is included in the received communication message, the switch SW flag 114 is set to “1” (“ON”) indicating that the checksum is added. That is, the switch SW flag 114 is set to “0” when the format of the data frame is “extended format F2”, and is set to “1” when the format is “special format F3”. When the data frame format is “basic format F1”, the set value of the switch SW flag 114 is not used.

The switch SW flag 114 is used to determine whether or not to set “checksum” in the communication message composed of “extended format F2” when transmitting the communication message. That is, when “0” is set in the switch SW flag 114, the information processing apparatus 11 sets “extended format F2” in which “checksum” is not added to the communication message to be transmitted, while “ When “1” is set, the information processing apparatus 11 sets “special format F3” in which “checksum” is added to the communication message. As described above, whether or not the information processing apparatus 11 includes the check value in the communication message can be selected based on the value set in the switch SW flag 114.

A value of “0” or “1” is set in the switching SW flag 114 based on the operation of the application 111. In this embodiment, when the operation of the application 111 is executed, the switching SW flag is set. 114 is set to “1”.

The CAN controller 12 is connected to the information processing apparatus 11 so as to be able to exchange data. The CAN controller 12 is connected to the information processing apparatus 11 so that various kinds of information can be exchanged, and is connected to the communication bus 16 via the physical layer interface 17. The physical layer interface 17 is a so-called CAN transceiver, and is electrically connected to the CAN controller 12 and the communication bus 16, and mutually converts electrical characteristics between the communication bus 16 and the CAN controller 12. As a result, communication messages can be transmitted in both directions between the communication bus 16 and the CAN controller 12.

The CAN controller 12 includes a transmission / reception circuit 121 that transmits and receives a communication message via the communication bus 16, and an ID filtering 122 that performs so-called message filtering that determines necessity / unnecessity of the received communication message. And are provided. The CAN controller 12 is provided with a changeover switch 125 for switching the filtering of the ID filtering 122 to the special filtering when the communication message is “special format F3”.

Further, the CAN controller 12 is provided with a CPU interface 123 for sending / receiving various data set in the communication message to / from the information processing apparatus 11. Further, the CPU interface 123 is provided with a message buffer 124 that is a readable / writable memory. The message buffer 124 includes a reception buffer area that can be read from the information processing apparatus 11 and a writable transmission buffer area. Is provided. Note that the reception buffer area and the transmission buffer area may share a predetermined area of the message buffer 124, or may secure different areas of the message buffer 124.

The transmission / reception circuit 121 realizes the CAN protocol function. When the communication message received from the communication bus 16 is received by the reception port Rx via the physical layer interface 17, the received communication message is received by the CAN protocol. Analyze based on At this time, the transmission / reception circuit 121 detects the presence / absence of alteration of the communication message based on CRC (Cyclic Redundancy Check) stipulated to be provided in a CAN protocol remote frame or data frame.

When the transmission / reception circuit 121 receives the target data (M3) to be transmitted to the communication bus 16 from the CPU interface 123, the transmission / reception circuit 121 creates a communication message including the target data (M3), CRC, and the like from the transmission port Tx. The data is transmitted to the communication bus 16 via the interface 17.

The changeover switch 125 is a switch for switching the filtering function executed by the ID filtering 122 depending on whether the communication message is “extended format F2” or “special format F3”. Switching is performed based on the switching SW flag 114 of the processing device 11. More specifically, the selector switch 125 is switched to “off” when the switch SW flag 114 of the information processing apparatus 11 is “0” (“off”), and filtering of the ID filtering 122 is performed with “basic ID” and “extended”. Based on “ID”. On the other hand, the selector switch 125 is switched to “ON” when the switch SW flag 114 is “1” (“ON”), and causes the filtering of the ID filtering 122 to be performed based only on “basic ID”. . That is, the changeover switch 125 is set to “off” when the communication message received by the first ECU 10 by the application 111 is “extended format F2”, and “on” when the communication message is “special format F3”. Is set to.

The ID filtering 122 sets whether the received communication message is a message required for the first ECU 10 or an unnecessary message in the “basic ID” or “extended ID” included in the data frame. It is determined based on applying the “ID filter value”. The ID filtering 122 sends a communication message determined to be necessary to the CPU interface 123, but stops sending a communication message determined to be unnecessary to the CPU interface 123 instead. That is, the ID filtering 122 performs so-called filtering that restricts transmission of communication messages to the CPU interface 123 so that only necessary communication messages are sent to the CPU interface 123. Thereby, the communication message determined to be necessary can use the “target data (M3)” in the first ECU 10, while the communication message determined to be unnecessary is the “target data”. Is not used in the first ECU 10.

In addition, since the “basic ID” and “extended ID” indicating the contents necessary for the first ECU 10 are set in the first ECU 10, the set “basic ID” and “extended ID” are set. Based on this, the ID filter value of the ID filtering 122 is set.

More specifically, when the ID filtering 122 determines that the received data frame is “standard format F1” based on the CAN protocol, the “basic ID” set in the “basic ID area” of “standard format F1”. Filtering based on (basic filtering). In addition, when the ID filtering 122 determines that the received data frame is “extended format F2” based on the CAN protocol, the ID filtering 122 sets “basic ID” and “extended ID region” set in the “basic ID region”. Filtering (extended filtering) is performed based on the “extended ID”. Further, the ID filtering 122 performs filtering (special filtering) based on the “basic ID” set in the “basic ID area” when the communication message is determined to be “special format F3”. That is, the ID filtering 122 performs “basic filtering”, “extended filtering”, and “special filtering” as filtering.

More specifically, the ID filtering 122 indicates that the bit following the “basic ID area” “RTR” (see FIG. 3A) is a dominant that is one of the two bus levels in the CAN protocol. If detected, the data frame is determined to be “standard format F1” and “basic filtering” is performed. Note that “RTR” is an abbreviation for remote transmission request.

The ID filtering 122 is a recessive in which “SRR” and “IDE” (see FIG. 3B), which are bits following the “basic ID area”, are the other levels of the two bus levels in the CAN protocol. When this is detected, the data frame is provisionally determined to be “extended format F2”. In addition to this temporary determination, when the changeover switch 125 is set to “off”, the ID filtering 122 determines that the format of the data frame is “extended format F2” and performs “extended filtering”. On the other hand, in addition to this temporary determination, when the changeover switch 125 is set to “ON”, the ID filtering 122 determines that the format of the data frame is “special format F3” and performs “special filtering”. . Note that “SRR” is an abbreviation for the Substitute Remote Request bit, and “IDE” is an abbreviation for the identifier extension bit.

That is, when the communication message is “extended format F2”, the ID filtering 122 selects “extended filtering” or “special filtering” based on whether the setting of the changeover switch 125 is “on” or “off”. I do. The “special filtering” is filtering performed when the communication message is in the “special format F3”, and is filtering performed based on only the “basic ID”, similarly to the “basic filtering”. As a result, the ID filtering 122 filters the communication message based only on the “basic ID”, and the data set in the “extended ID area” (checksum in the present embodiment) as in the “extended filtering”. Is sent to the CPU interface 123. That is, “special filtering” is different from “extended filtering” in that filtering is performed only by “basic ID”, while sending a communication message to the CPU interface 123 is performed in the same manner.

That is, in this embodiment, the ID filtering 122 determines that the format of the communication message is “special format F3” based on the “ON” setting by the changeover switch 125 and executes “special filtering”. As a result, the ID filtering 122 sends the data stored in the “extended ID area” of the communication message that has not been used for filtering, to the CPU interface 123. Accordingly, the information processing apparatus 11 can handle the data stored in the “extended ID area” as, for example, “checksum” based on the setting of the switching SW flag 114.

On the other hand, the ID filtering 122 transmits the communication message for transmission received from the CPU interface 123 to the transmission / reception circuit 121 as it is. The ID filtering 122 may confirm “basic ID”, “extended ID”, “checksum”, and the like included in the communication message for transmission.

The CPU interface 123 enables transmission / reception of communication messages between the CAN controller 12 and the information processing apparatus 11 via the message buffer 124. That is, in the message buffer 124, the data buffer area can read and write data by the CPU interface 123, and can read and write data from the information processing apparatus 11.

The message buffer 124 is provided with a reception buffer in which data in each storage area of the communication message received by the first ECU 10 is stored in a predetermined area corresponding to the storage area. The reception buffer is provided with “basic ID buffer area”, “extended ID buffer area”, “data length buffer area”, “target data buffer area”, and the like as predetermined areas. When the message buffer 124 receives the communication message, the “basic ID” is set in the “basic ID buffer area”, the “extended ID” is set in the “extended ID buffer area”, and the “data length” is set in the “data length buffer area”. The “target data” is stored in the “target data buffer area”. As a result, “basic ID (M1)” is stored in the “basic ID buffer area”, “extended ID (M2)” is displayed in the “extended ID buffer area”, and “target data (M3)” is displayed in the “target data buffer area”. Each is stored. When the changeover switch 125 is “off”, “extended ID” is stored in the “extended ID buffer area” of the reception buffer, while when the changeover switch 125 is “on”, the format of the communication message is “special format”. Since it is “F3”, “Checksum (M2)” is stored in the “Extended ID buffer area” of the reception buffer.

In this reception buffer, each of the predetermined areas described above can be read by the information processing apparatus 11. That is, when the information processing apparatus 11 detects that data is stored in the reception buffer, the information processing apparatus 11 can read data in each storage area of the received communication message that has passed through the ID filtering 122 via the reception buffer. . For example, the information processing apparatus 11 receives “basic ID” from the “basic ID buffer area” of the reception buffer, “extended ID” from the “extended ID buffer area”, “data length” from the “data length buffer area”, Obtain “target data” from the “target data buffer area”. The “target data” is data including all or a part of the transferred information. The information processing apparatus 11 determines the content of the corresponding “target data (M3)” based on “basic ID (M1)” and “extended ID (M2)”. Further, the information processing apparatus 11 acquires the “extended ID” from the “extended ID buffer area” when the switch SW flag 114 is “off”, while the communication message format when the switch SW flag 114 is “on”. Is “special format F3”, “checksum (M2)” is acquired from the “extended ID buffer area” of the reception buffer.

Further, the message buffer 124 is provided with a transmission buffer in which data corresponding to each storage area of the communication message transmitted by the first ECU 10 is stored in a predetermined area corresponding to each storage area. In the transmission buffer, a “basic ID buffer area”, an “extended ID buffer area”, a “data length buffer area”, a “target data buffer area”, and the like are provided as predetermined areas. In the transmission buffer, each of the predetermined areas described above can be written from the information processing apparatus 11.

In the message buffer 124, the “basic ID (M1)” is stored in the “basic ID buffer area” of the transmission buffer, the “extended ID (M2)” is stored in the “extended ID buffer area”, and the “data” is stored in the message buffer 124. “Data length” is stored in the “long buffer area”, and “target data (M3)” is stored in the “target data buffer area”. The information processing apparatus 11 stores the “extended ID” in the “extended ID buffer area” when the switch SW flag 114 is “off”, while the communication message format is changed when the switch 125 is “on”. Since the “special format F3” is selected, “checksum 113” is stored in the “extended ID buffer area” of the transmission buffer.

When the transmission / reception circuit 121 detects that the data is stored in the transmission buffer, the transmission / reception circuit 121 acquires each data stored from the transmission buffer, and the acquired data includes a “basic ID (M1)” and an “extended ID (M2)”. ) "," Data length ", and" target data (M3) "are generated. The transmission / reception circuit 121 acquires the “extended ID” from the “extended ID buffer area” when the changeover switch 125 is “off”, while the communication message format is “special” when the changeover switch 125 is “on”. Since “format F3” is selected, “checksum (M3)” is acquired from the “extended ID buffer area” of the transmission buffer.

Such an operation of the communication apparatus will be described with reference to FIGS.

First, filtering will be described with reference to FIG.

When receiving the communication message from the transmission / reception circuit 121, the ID filtering 122 starts executing filtering. When filtering is executed, the received communication message is filtered based on the “basic ID” (step S10). If it is determined by filtering that the communication message is unnecessary, the execution of filtering is terminated. In order to distinguish the format type of the data frame of the communication message determined as the communication message necessary for the execution of filtering, it is determined whether or not “IDE” is dominant (step S11).

When it is determined that “IDE” is dominant, that is, when it is determined that the data frame is “standard format F1” (YES in step S11), the ID filtering 122 is stored in each information area of the communication message. Are written to the corresponding areas of the reception buffer provided in the message buffer 124 (step S13). At this time, since the data frame is “standard format F1”, “standard ID (M1)”, “data length”, and “target data (M3)” are written in the reception buffer (“standard”). Writing). Then, the execution of filtering is terminated.

On the other hand, when it is determined that “IDE” is not dominant (NO in step S11), the ID filtering 122 determines whether or not the changeover switch 125 is set to “ON” (step S14). When it is determined that the changeover switch 125 is not “ON” (NO in step S14), the ID filtering 122 performs so-called “extended filtering” that performs filtering based on the “basic ID” and the “extended ID”. (Step S15). If the filtering determines that the message is an unnecessary communication message, the filtering is terminated. When it is determined that the message is a communication message necessary for the execution of this filtering, the ID filtering 122 transfers the data stored in each information area of the communication message to the corresponding area of the reception buffer provided in the message buffer 124. Each is written (step S16). At this time, since the data frame is “extended format F2”, the “standard ID (M1)”, “extended ID (M2)”, “data length”, and “target data (M3) are stored in the reception buffer. ) "Is written (" extension "is written). Then, the execution of filtering is terminated.

When the changeover switch 125 is “ON” (YES in step S14), the ID filtering 122 uses the data stored in each information area of the communication message in the corresponding area of the reception buffer provided in the message buffer 124. (Step S18). At this time, since the data frame is “special format F3”, the “standard ID (M1)”, “extended ID (M2)”, “data” are stored in the reception buffer as in “extended format F2”. "Length" and "Target data (M3)" are written ("Extension" is written). Then, the execution of filtering is terminated.

At this time, the data set in the “extended ID area” of the communication message is written in the “extended ID buffer area” of the reception buffer. However, since the format of the data frame is “special format F3”, the value stored in the “extended ID area” is not “extended ID” but “checksum”. “Checksum” is stored in “.”.

Next, data processing by the information processing apparatus 11 will be described with reference to FIG.

When the information processing apparatus 11 detects that the data included in the communication message is set in the reception buffer, the information processing apparatus 11 starts predetermined data processing. When the predetermined data processing is started, the information processing apparatus 11 determines whether or not the switch SW flag 114 is “1” (“ON”) (step S20).

When it is determined that the switching SW flag 114 is not “1” (“ON”), that is, when it is determined that it is “0” (“OFF”) (NO in step S20), the information processing apparatus 11 Data set in each buffer area of the reception buffer is acquired (read) (step S21). The information processing apparatus 11 determines the content of the “arbitrary data 112” including the “target data (M3)” based on the read “standard ID (M1)” and “extended ID (M2)”, and The “arbitrary data 112” is subjected to predetermined data processing as it is (step S22). For example, the information processing apparatus 11 determines that the content of “arbitrary data 112” is “speed” of the vehicle 1 based on “standard ID”, and is set to “arbitrary data 112” in the processing of the application 111. The value is used as “speed”.

On the other hand, when it is determined that the switch SW flag 114 is “1” (“ON”) (YES in step S20), the information processing apparatus 11 acquires data set in each buffer area of the reception buffer ( Read) (step S23). That is, the information processing apparatus 11 obtains “standard ID (M1)” from the “standard ID buffer area” of the reception buffer, “checksum (M2)” from the “extended ID buffer area”, and “target data buffer area”. “Arbitrary data 112” is acquired. Then, the information processing apparatus 11 applies a predetermined algorithm for verification to the “arbitrary data 112” and the “checksum 113” to determine whether or not an error has occurred in the data of the “arbitrary data 112”. Detect (step S24). That is, the information processing apparatus 11 detects whether or not a so-called error has occurred in which the data of “arbitrary data 112” has been altered. Thereby, after the alteration is checked by “CRC” in the transmission / reception circuit 121, the alteration of the data generated in the “arbitrary data 112 (target data (M3))” is detected before reaching the information processing apparatus 11. Will be able to.

If no alteration (error) is detected by detecting the presence / absence of alteration (NO in step S25), the information processing apparatus 11 performs the same processing as in step S22 on the “arbitrary data 112” that has not been altered. Then, predetermined data processing is performed (step S22).

On the other hand, when a modification (error) is detected by detecting the presence or absence of modification (YES in step S25), the information processing apparatus 11 does not use the modified “arbitrary data 112” for predetermined data processing and In order to obtain an accurate value that has not been received, a retransmission request is made based on the “standard ID” corresponding to the “arbitrary data 112” (step S26). That is, the information processing apparatus 11 causes the CAN controller 12 to issue a remote frame, which is a communication message for requesting data, based on the “standard ID”. The remote frame based on the “standard ID” thus issued causes the second ECU 13 to reissue a data frame including “target data” corresponding to the “standard ID”. Thus, even if the information processing apparatus 11 acquires the “arbitrary data 112” whose value has been modified, the information processing apparatus 11 thereafter receives a data frame corresponding to the “standard ID” reissued from the second ECU 13. In a short time, it is possible to obtain appropriate “arbitrary data 112” corresponding to the “standard ID” whose value is not altered.

By detecting the modification of the value of “arbitrary data 112” in this way, the reliability of the value of “arbitrary data 112” used for execution of the application 111 is enhanced, and thus the reliability is improved. The reliability of the execution result of the application 111 performed using the value of the “arbitrary data 112” is also improved.

As described above, the communication system including the communication device according to the present embodiment has the effects listed below.

(1) In the CAN protocol, for example, the CAN controller 12 of the first ECU 10 changes the target data (M3) to be transferred between the two CAN controllers 12 and 15 and the target data (M3). The checksum (M2) for detecting presence / absence can be acquired from one communication message (one frame). As described above, since the target data (M3) and the checksum (M2) transferred between the two CAN controllers 12 and 15 can be acquired from one communication message, the checksum M2 is acquired as a separate communication message. Compared to the above, it is possible to reduce the amount of communication messages in the network. As a result, it is possible to reduce overhead generated for each communication message, arbitration during transmission, and the like. The data area corresponds to a data field defined in the CAN protocol. The data field is an area where the user can freely define the content (data), and the content (data) defined by the user in the same area is the target data (M3).

Further, since the CAN controller 12 can acquire the target data (M3) and the checksum (M2) from one communication message, respectively, when the target data (M3) and the checksum (M2) are sent in different communication messages. It is possible to omit management of the correspondence between two required communication messages. For this reason, detection of modification of the target data (M3) is simplified, and convenience is improved. For example, the device that processes the transferred target data eliminates the waiting time until the checksum is sent after acquiring the target data, or requests the retransmission of the check value when the check value cannot be received. This makes it possible to omit processing to be performed.

(2) For example, the CAN controller 12 of the first ECU 10 can use the checksum (M2) added without changing the “extended format F2”. Actually, there are many CAN controllers that use only the basic ID and do not use the extended ID. In such a CAN controller that does not use the extended ID, the presence or absence of modification of the target data is detected only by using the extended ID area. A checksum (M2) is easily added. In addition, it becomes easy to change an existing apparatus compatible with the CAN protocol to such a CAN controller.

(3) For example, when the CAN controller 12 of the first ECU 10 determines that the format is “special format F3”, the “checksum M2” added to the “extended ID” is added to perform filtering using only the “basic ID”. "Is prevented from affecting the message filtering performed by the ID filtering 122. As a result, the communication message to which the check value is added can be more suitably processed.

(4) If the setting of the changeover switch 125 is set to “off”, the CAN controller 12 uses the area storing the “extended ID” as if the “extended ID” which is the original use in the CAN protocol is stored. As a result, the versatility of the communication apparatus can be improved.

(5) For example, the information processing device 11 of the first ECU 10 detects whether or not the arbitrary data 112 is modified based on the acquired target data (M3) by using the checksum 113 included in the same communication message. Thus, since the arbitrary data 112 based on the target data (M3) and the checksum 113 can be acquired from the same communication message, the process for detecting the presence / absence of alteration is accelerated.

(6) In the CAN communication protocol, for example, the CAN controller 15 of the second ECU 13 includes target data (M3) to be transferred between the two CAN controllers 12 and 15, and the target data (M3). The checksum (M2) for detecting the presence or absence of alteration can be stored in one communication message (one frame). In this way, if the target data (M3) and the checksum (M2) transferred between the two CAN controllers 12 and 15 are stored in one communication message, the checksum (M2) is transmitted in a separate communication message. Compared with the case where it carries out, the communication amount of the communication message in a network can be reduced. As a result, it is possible to reduce overhead generated for each communication message, arbitration during transmission, and the like.

Also, for example, the CAN controller 15 of the second ECU 13 stores the target data (M3) and the checksum (M2) in one communication message. This makes it possible to omit the management of the correspondence between the two communication messages required when sending the target data (M3) and the checksum (M2) in different communication messages, improving convenience. To do. For example, the device that transmits the target data may eliminate the waiting time until the checksum is transmitted after transmitting the target data, or may omit processing corresponding to a retransmission request for one of the two. become able to.

(7) For example, the CAN controller 15 of the second ECU 13 can add the checksum (M2) without changing the “extended format F2”. Actually, there are many CAN controllers that use only the basic ID and do not use the extended ID. In such a CAN controller that does not use the extended ID, whether or not the target data (M3) is altered only by using the extended ID area. It is possible to easily add a checksum (M2) for detecting. It is also easy to change an existing apparatus that supports the CAN protocol to such a CAN controller 12.

(8) For example, if the setting of the changeover switch 125 is “OFF”, the CAN controller 15 of the second ECU 13 can store the extended ID, which is the original application, in the area for storing the extended ID. Thus, the versatility of the communication device can be improved.

(9) In the CAN protocol, the communication system includes target data (M3) to be transferred between the two CAN controllers 12 and 15, and a checksum (M2) that detects whether the target data (M3) has been altered. ) Can be stored in one communication message (one frame). Then, the target data (M3) and the checksum (M2) stored in the communication message can be acquired from the one communication message.

In this way, if the target data (M3) and the checksum (M2) transferred between the two CAN controllers 12 and 15 are stored in one communication message and transmitted and received, the checksum ( Compared with the case where M2) is transmitted and received as a separate communication message, the communication volume of the communication message in the network can be reduced. As a result, the overhead generated for each communication message in the communication system, arbitration during transmission, and the like can be reduced.

Further, the communication system can store and receive the target data (M3) and the checksum (M2) in one communication message. From this, it becomes possible to omit the management of the correspondence between two communication messages, which is necessary when the target data (M3) and the checksum (M2) are sent in different communication messages. Convenience is improved. For example, the device that transmits the target data (M3) and the device that receives the target data (M3) receive the target data (M3) and then wait until the next checksum (M2) is transmitted and received. Or the processing corresponding to the retransmission request for one of the two communication messages can be omitted. Thereby, a quick communication can be performed as a communication system.

(Second Embodiment)
A second embodiment that embodies a communication system including a communication apparatus according to the present invention will be described with reference to FIG. In the present embodiment, a part of the processing in the first ECU 10A and the second ECU 13A is different from the first ECU 10 and the second ECU 13 in the first embodiment, but the other configurations are the same. Therefore, here, differences in processing will be described, and detailed description of similar configurations will be omitted. That is, it is assumed that the first ECU 10A and the second ECU 13A can support “basic format F1,” “extended format F2,” and “special format F3”.

In the present embodiment, the first ECU 10A changes the data frame format of the communication message between the second ECU 13A and the first ECU 10A to one of the “extended format F2” or the “special format F3” as necessary. It is possible to select and switch to the selected format as appropriate.

More specifically, in the first ECU 10A, the value of the switch SW flag 114 is appropriately set to either “0” (“off”) or “1” (“on”) depending on the application executed there. It has become so. Similarly, in the second ECU 13A, the value of the switch SW flag is appropriately set to “0” or “1” depending on the application executed there. Each of the first ECU 10A and the second ECU 13A indicates that the data frame is “extended format F2” when the value of the switch SW flag is “0”, that is, “extended ID” is set in the “extended ID area”. This corresponds to the stored method (extended method). On the other hand, each of the first ECU 10A and the second ECU 13A, when the value of the switch SW flag is “1”, indicates that the data frame is “special format F3”, that is, “extended ID area” has “checksum”. This corresponds to the stored method (special method).

As shown in FIG. 6, when the application executed by the first ECU 10A changes the value of the switching SW flag from “0” to “1”, the first ECU 10A sets the switching SW flag of the second ECU 13A. A switching message for changing the value from “0” to “1” is transmitted to the second ECU 13A (step S30). For example, the first ECU 10A transmits a communication message (data frame) having “basic ID” as a message for switching the value of the switch SW flag from “0” to “1” to the network. Receiving the communication message, the second ECU 13A processes the communication message with an application, and changes the value of the switching SW flag from “0” to “1” by the application (step S31). Thereby, the first ECU 10A and the second ECU 13A are respectively switched from the expansion method to the special method, and correspond to the special method. Note that the switching message may be a remote frame, and in that case, the first ECU 10A may obtain the switching result from the second ECU 13A.

After changing the value of the switch SW flag of the second ECU 13A from “0” to “1”, the first ECU 10A transmits a communication message (remote frame) requesting data constituting predetermined information ( Step S32). At this time, a “basic ID” indicating predetermined information that needs to be transmitted by the second ECU 13A is set in the communication message.

The second ECU 13A that has received the communication message requesting the data constituting the predetermined information generates data for transmission from the required predetermined information (step S33), and uses it for detection of alteration of the data. Calculate the checksum to be used. Then, the calculated transmission data and checksum are stored in the corresponding areas of the “extended format F2”, that is, the “target data area” and the “extended ID area” (step S34). Since the value of the switch SW flag is “1”, the data frame is “extended format F2”. However, the first ECU 10A and the second ECU 13A process the data frame as “special format F3”. It has become. Then, the second ECU 13A transmits the communication message storing the transmission data and the checksum to the network (step S35).

The first ECU 10A receives the communication message transmitted from the second ECU 13A corresponding to the previously transmitted “basic ID” (step S36) and executes processing such as filtering (step S37). That is, since the first ECU 10A performs filtering by “special filtering” on the communication message, the first ECU 10A filters the communication message only by “basic ID”.

On the other hand, the first ECU 10A obtains the “checksum” from the “extended ID area” and sets it in the “extended ID buffer area” of the reception buffer (step S38). Based on the fact that the switch SW flag is “1”, the first ECU 10A determines that the data in the “extended ID area” of the reception buffer is “checksum”. Therefore, the first ECU 10A detects whether or not the “arbitrary data” obtained from the “target data area” of the reception buffer has been modified based on the above-mentioned “checksum”, and detects that it has not been modified. The acquired “arbitrary data” is used for application processing (step S39). When it is detected that “arbitrary data” has been altered, a request is made to retransmit a communication message including the “arbitrary data (target data)” as in the first embodiment.

In this way, after all the information transferred from the second ECU 13A has been transferred to the first ECU 10A via one or more communication messages, the first ECU 10A receives the first ECU 10A and the second ECU 10A. The value of the switch SW flag of the ECU 13A is returned to “0”. That is, in the first ECU 10A, the value of the switching SW flag is returned from “1” to “0” by the application executed there, and the value of the switching SW flag of the second ECU 13A is changed from “1” to “0”. A communication message (data frame) to be returned to is transmitted to the second ECU 13A (step S40). Then, the second ECU 13A that has received the switching communication message processes the communication message by an application, and changes the value of the switching SW flag from “1” to “0” by the application (step S41). Thereby, the first ECU 10A and the second ECU 13A are respectively switched from the special method to the expansion method, and correspond to the expansion method.

As described above, the communication system including the communication device according to the present embodiment has the effects listed below in addition to the effects (1) to (9) described in the first embodiment.

(10) Since the CAN controller of the second ECU 13A that transmits the communication message is set by the CAN controller of the first ECU 10A that receives the communication message, whether or not to store the checksum in the communication message is set as the communication system. It becomes easy to switch the setting of whether or not to store the checksum in the communication message transmitted and received. Thereby, the applicability of such a communication system is enhanced.

(Other embodiments)
In addition, each said embodiment can also be implemented with the following aspects.

In the second embodiment, the case where the first ECU 10A on the data receiving side changes the value of the switching SW flag of the second ECU 13A on the data transmitting side is exemplified. However, the present invention is not limited to this, and the ECU on the data transmission side may change the value of the switch SW flag of the ECU on the data reception side. For example, as shown in FIG. 7, when the value of the switch SW flag of the second ECU 13B is changed from “0” to “1” in order to enable transmission / reception of the communication message of “special format F3”, the second The ECU 13B transmits a communication message for changing the value of the switch SW flag of the first ECU 10B from “0” to “1” to the first ECU 10B (step S50). The first ECU 10B that has received the communication message may change the value of the switch SW flag from “0” to “1” by an application that processes the communication message (step S51).

Then, when the transfer of information is completed, the second SW 13B switch SW flag is changed from “1” to “0” in order to cancel the response to the communication message of “special format F3”. The ECU 13B transmits a communication message for changing the value of the switch SW flag of the first ECU 10B from “1” to “0” to the first ECU 10B (step S52). The first ECU 10B that has received the communication message may change the value of the switch SW flag from “1” to “0” by an application that processes the communication message (step S51).

Thus, the CAN controller that receives the communication message sets whether or not the check sum is stored in the communication message by the CAN controller that transmits the communication message. It becomes easy to switch the setting of whether or not to store. That is, the applicability of such a communication system is increased and the degree of freedom in design is increased.

In each of the above embodiments, the case where the filtering executed by the ID filtering 122 is switched to “extended filtering” or “special filtering” by the changeover switch (switching SW flag) is illustrated. However, the present invention is not limited to this, and filtering performed by ID filtering may be only “special filtering”. For example, if the communication system uses only the “basic format” for communication messages, the system does not need to support the extended format. May always apply “special filtering”. As a result, the possibility that the “special format” for storing the target data and the checksum corresponding to the target data in one communication message can be applied to the communication system configured by the CAN network is improved.

In the above embodiment, the case where the “checksum” is used as the check value for the detection of the modification of the “target data (arbitrary data 112)” acquired from the “data area” of the data frame is exemplified. However, the present invention is not limited to this, and if the modification of “arbitrary data” acquired from the “data area” can be detected, so-called error detection is possible, the value used for the check value is calculated based on what algorithm It may be a value, such as a CRC. Thereby, the design freedom of a communication system can be improved.

In each of the above embodiments, the case where the two ECUs 10 (10A) and 13 (13A) are connected to the communication bus 16 is illustrated. However, the present invention is not limited to this, and three or more ECUs may be connected to the communication bus so as to be able to communicate with each other. This increases the availability of the communication system.

At this time, an ECU that is not compatible with a communication message of “special format” in which “checksum” is included in the “extended ID” is connected in the ECU connected to the communication bus. Also good. In this case, if the unsupported ECU is set so that the communication message can be determined to be unnecessary based on the “basic ID”, no inconvenience occurs even if the corresponding ECU and the unsupported ECU are mixed. . If the ECU corresponding to the “special format F3” and the non-corresponding ECU can be mixed, the application of the communication device to the communication system is facilitated and the applicability is enhanced.

In each of the above embodiments, the case where information necessary for control is transferred between the first ECU 10 (10A) and the second ECU 13 (13A) is illustrated. However, the present invention is not limited thereto, and information based on update control program data, so-called repro data, update parameters, and the like may be transferred between the first ECU and the second ECU. Thereby, the utility value of this communication apparatus comes to be raised.

DESCRIPTION OF SYMBOLS 1 ... Vehicle 10, 10A, 10B ... 1st ECU (1st electronic control apparatus), 11 ... Information processing apparatus, 12, 15 ... CAN controller, 13, 13A, 13B ... 2nd ECU, 14 ... Information Processing unit 16 ... Communication bus, 17 ... Physical layer interface, 111 ... Application, 112 ... Arbitrary data, 113 ... Checksum, 114 ... Switch SW flag, 121 ... Transmission / reception circuit, 122 ... ID filtering, 123 ... CPU interface, 124 ... Message buffer, 125 ... Changeover switch, 141 ... Application, M1 ... Basic ID, M2 ... Extended ID (checksum), M3 ... Target data.

Claims

A communication device that receives a communication message transferred between communication devices based on a communication protocol applied to a control area network,
The target data is stored in a target data storage area defined in one frame as an area for storing target data included in the communication message, and the target data storage area in the same frame is different from the target data storage area. By receiving a communication message storing a check value used for detecting whether or not the target data is altered, from the received communication message, together with the target data stored in the target data storage area, A communication apparatus, wherein the check value stored in an area different from the target data storage area is acquired together.
The communication message is configured as an extended format defined by a communication protocol applied to the control area network,
The communication apparatus according to claim 1, wherein an extension ID area that stores an extension ID defined in the extension format is used as an area different from the target data storage area in which the check value is stored.
The communication device according to claim 2, wherein message filtering for determining whether the communication message is necessary or not is performed based only on a basic ID included in the extended format.
Whether or not to include the check value in the communication message can be selected, and when it is selected not to include the check value, the extension ID stored in the extension ID area of the communication message is set to the extension ID area. The communication apparatus according to claim 3, wherein the communication apparatus is used together with a basic ID for the message filtering.
The communication device according to any one of claims 1 to 4, further comprising a processing device that detects presence or absence of alteration of the target data based on a check value acquired together with the received target data.
A communication device for transmitting a communication message transferred between communication devices based on a communication protocol applied to a control area network,
The target data is stored in a target data storage area defined in one frame as a target data storage area included in the communication message, and the target data is stored in a different area from the target data storage area in the same frame. A communication device that stores a check value used to detect whether data has been altered and generates the communication message to be transmitted.
The communication message is configured as an extended format defined by a communication protocol applied to the control area network,
The communication apparatus according to claim 6, wherein an extension ID area for storing an extension ID defined in the extension format is used as an area different from the target data storage area for storing the check value.
8. It is possible to select whether to store the check value in the extended ID area, and when it is selected not to store the check value, the check value is not stored in the extended ID area. The communication device described.
A communication system for transmitting and receiving communication messages transferred between communication devices based on a communication protocol applied to a control area network,
The communication device according to any one of claims 6 to 8 is used as a communication device that transmits the communication message, and the communication device according to any one of claims 1 to 5 is used as a communication device that receives the communication message. A communication system characterized by using the communication device.
A communication system for transmitting and receiving communication messages transferred between communication devices based on a communication protocol applied to a control area network,
The communication device according to claim 8 is used as a communication device that transmits the communication message, and the communication device according to claim 4 is used as a communication device that receives the communication message.
The communication device that transmits the communication message further includes a function of sending a message notifying whether or not to store the check value in the extended ID area,
Whether or not the communication device that receives the communication message includes the check value in the extended ID area based on obtaining a message for notifying whether or not to store the check value in the extended ID area A communication system, further comprising a function of recognizing the above.
A communication system for transmitting and receiving communication messages transferred between communication devices based on a communication protocol applied to a control area network,
The communication device according to claim 8 is used as a communication device that transmits the communication message, and the communication device according to claim 4 is used as a communication device that receives the communication message.
The communication device that receives the communication message is further provided with a function of sending a message for requesting storage of the check value in the extension ID,
The communication device that transmits the communication message is further provided with a function of storing the check value in the extension ID area based on obtaining a message for requesting storage of the check value in the extension ID. A communication system.
A communication method for receiving a communication message transferred between communication devices based on a communication protocol applied to a control area network,
The target data is stored in a target data storage area defined in one frame as an area for storing the target data included in the communication message, and the target data storage area in the same frame is different from the target data storage area. Receiving a communication message in which a check value used for detecting whether or not the target data is altered is stored; obtaining target data stored in the target data storage area from the received communication message; And obtaining the check value stored in an area different from the target data storage area from the received communication message.
A communication method for transmitting a communication message transferred between communication devices based on a communication protocol applied to a control area network,
As a step prior to the step of transmitting the communication message, a step of storing the target data in a target data storage area defined in one frame as an area for storing the target data included in the communication message; Storing a check value used for detecting whether or not the target data has been modified in an area different from the target data storage area.
A communication method for performing transmission and reception of a communication message transferred between communication devices based on a communication protocol applied to a control area network, by mutual communication between the communication devices,
The communication method according to claim 13, wherein the communication device that transmits the communication message transmits the communication message.
The communication method according to claim 12, wherein a communication device that receives the communication message receives the communication message.
A communication method transmitted from a communication device that transmits the communication message is acquired by a communication device that receives the communication message.