CAN (Controller Area Network) bus for simultaneously transmitting standard frame message and expanded frame message and configuration method

Abstract

The invention discloses a CAN (Controller Area Network) bus for simultaneously transmitting a standard frame message and an extended frame message and a configuration method, comprising: a CanIf layer used for distributing a CAN message to a CAN interface according to a CAN bus cluster and a CAN ID in a CAN message description file, and creating and configuring a parameter container for receiving or sending a protocol data unit; the CanTp layer comprises a channel only used for a standard frame message or an expanded frame message, and configuration of a corresponding service data receiving or sending unit; the PDuR layer comprises routing configuration for the standard frame message and the expanded frame message; the EcuC layer comprises a global protocol data unit; a communication driver of the microcontroller abstraction layer comprises at least two paths of first CAN mailboxes used for receiving and transmitting expansion frame messages and a first CAN mailbox used for receiving and transmitting standard frame messages, and the microcontroller abstraction layer further comprises a second CAN mailbox corresponding to the first CAN mailboxes. According to the invention, the standard frame message and the expanded frame message of the CAN can be transmitted on the same CAN line.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile open system architecture, and in particular to a CAN bus for simultaneously transmitting standard frame messages and extended frame messages and a configuration method thereof. Background Art

[0002] Currently, most passenger cars use CAN standard frame messages, while most commercial vehicles use CAN extended frame messages. However, many controllers can be used in both passenger cars and commercial vehicles. This results in the same controller having the same hardware but different CAN message frame formats, and the same software cannot be used at the same time. Therefore, there is an urgent need for a configuration method for adding extended frame messages to the CAN standard frame under the Autosar architecture, so as to realize the transmission of standard frames and extended frames of CAN messages on one CAN line, thereby realizing the reuse of the same controller on passenger cars and commercial vehicles. Summary of the invention

[0003] The main purpose of the present invention is to provide a CAN bus and a configuration method for simultaneously transmitting standard frame messages and extended frame messages, so as to realize the simultaneous use of CAN standard frame messages and extended frame messages on the same CAN line of the same controller.

[0004] The technical solution adopted by the present invention is: a CAN bus for simultaneously transmitting standard frame messages and extended frame messages, comprising:

[0005] The CanIf layer is used to assign CAN messages to CAN interfaces according to the CAN bus cluster and CAN ID in the CAN message description file, and to create and configure parameter containers for receiving protocol data units and sending protocol data units;

[0006] The CanTp layer includes channels used only for standard frame messages and channels used only for extended frame messages, as well as the corresponding configurations of receiving service data units and sending service data units;

[0007] The PduR layer includes a routing table, wherein the routing table is provided with routing configurations for the standard frame message and the extended frame message;

[0008] EcuC layer, the EcuC layer is a virtual module, including global protocol data units corresponding to the configuration of each layer;

[0009] The microcontroller abstraction layer includes at least two first CAN mailboxes for sending and receiving extended frame messages, and a first CAN mailbox for sending and receiving standard frame messages in its communication driver, and the microcontroller abstraction layer also includes a second CAN mailbox corresponding to the first CAN mailbox. Furthermore, the CAN mailbox receives messages using a first-in-first-out mode.

[0010] According to the above technical solution, the CAN message includes an extended frame message and a standard frame message, which is related to the control function.

[0011] According to the above technical solution, the parameter container configuration content of the receiving protocol data unit includes: CANID, data length, message receiving node and response sequence number; the parameter container configuration content of the sending protocol data unit includes: CANID, data length, message sending node and response sequence number.

[0012] According to the above technical solution, the CAN ID of the parameter container of the receiving protocol data unit is the CAN extended frame message ID.

[0013] According to the above technical solution, the configuration of receiving the service data unit and sending the service data unit includes parameters CanTpBs, CanTpNar, CanTpNbr, CanTpNcr, CanTpSTmin, CanTpRxTaType and CanTpRxPaddingActivation.

[0014] According to the above technical solution, the global protocol data unit corresponding to each layer configuration includes a global protocol data unit associated with the extended frame message.

[0015] According to the above technical solution, the CAN hardware object in the communication driver in the microcontroller abstraction layer is of an extended type.

[0016] Another aspect of the present invention provides a method for configuring a CAN bus for simultaneously transmitting a standard frame message and an extended frame message, comprising:

[0017] Configure the communication driver of the microcontroller abstraction layer and add two first CAN mailboxes for sending and receiving extended frame messages;

[0018] In the CanIf layer, CAN messages are assigned to CAN interfaces according to the CAN bus cluster and CAN ID in the description file of the CAN message, and parameter containers of the receive protocol data unit and the send protocol data unit are created and configured;

[0019] In the CanTp layer, add a channel only for extended frame messages, and add the configuration of receiving service data units and sending service data units;

[0020] At the PduR layer, adding routing configuration for the standard frame message and the extended frame message;

[0021] In the virtual module EcuC layer, a global protocol data unit corresponding to the configuration added in each layer is added;

[0022] The microcontroller abstraction layer is configured again, and two second CAN mailboxes corresponding to the two first CAN mailboxes are added.

[0023] A third aspect of the present invention provides a computer storage medium storing a computer program executable by a processor, wherein the computer program executes the above-mentioned method for configuring a CAN bus for simultaneously transmitting standard frame messages and extended frame messages.

[0024] A fourth aspect of the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer device executes the above-mentioned method for configuring a CAN bus that simultaneously transmits standard frame messages and extended frame messages.

[0025] The beneficial effects of the present invention are as follows: the present invention provides a CAN bus and a configuration method for simultaneously transmitting standard frame messages and extended frame messages. Compared with a CAN bus that can only transmit standard frames or extended frame messages, the communication driver of the microcontroller abstract layer of the CAN bus includes a CAN mailbox for sending and receiving extended frame messages and a CAN mailbox for sending and receiving standard frame messages. The configuration for the standard frame message and the extended frame message is correspondingly set in the CanIf layer, the CanTp layer, the PduR layer and the virtual module EcuC layer, so as to realize the association between the layers of the CAN bus and the bottom chip and the CAN module when transmitting the standard frame message or the extended frame message. The CAN bus of the present invention can realize the simultaneous transmission of standard frame messages and extended frame messages. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the structure of a CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to an embodiment of the present invention;

[0028] Figure 2 A flow chart of a configuration method for a CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to an embodiment of the present invention;

[0029] Figure 3 A configuration diagram of a communication driver in a microcontroller abstraction layer according to an embodiment of the present invention;

[0030] Figure 4 It is a configuration diagram of the CanIf layer of an embodiment of the present invention;

[0031] Figure 5 It is a configuration diagram of the CanTp layer of an embodiment of the present invention;

[0032] Figure 6 is a configuration diagram of the PduR layer of an embodiment of the present invention;

[0033] Figure 7 A configuration diagram of the EcuC layer according to an embodiment of the present invention;

[0034] Figure 8 It is a configuration diagram of the microcontroller abstraction layer of an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0037] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0038] Example 1

[0039] This embodiment provides a CAN bus that transmits standard frame messages and extended frame messages at the same time, and the structure is as follows: Figure 1 As shown. Includes:

[0040] The CanIf layer is used to assign CAN messages to CAN interfaces according to the CAN bus cluster and CAN ID in the description file of the CAN message, and to create and configure the parameter containers of the receiving protocol data unit and the sending protocol data unit. Among them:

[0041] CAN messages include extended frame messages and standard frame messages, and are communication messages related to control functions.

[0042] The parameter container configuration content of the receiving protocol data unit includes: CAN ID, data length, message receiving node and response sequence number. The parameter container configuration content of the sending protocol data unit includes: CANID, data length, message sending node and response sequence number.

[0043] The CAN ID of the parameter container of the received protocol data unit is the CAN extended frame message ID.

[0044] Specifically, the CAN interface is CanIfInitHohCfg, the parameter container of the receiving protocol data unit is CanIfTxPduCfg, the parameter container of the sending protocol data unit is TxIndicationUL, and the response sequence number is PduRef.

[0045] The CanTp layer includes channels used only for standard frame messages and channels used only for extended frame messages, as well as the corresponding configurations of receiving service data units and sending service data units. Among them:

[0046] The configuration of receiving the service data unit and sending the service data unit includes parameters CanTpBs, CanTpNar, CanTpNbr, CanTpNcr, CanTpSTmin, CanTpRxTaType and CanTpRxPaddingActivation.

[0047] The PduR layer includes a routing table, wherein the routing table is provided with routing configurations for the standard frame message and the extended frame message.

[0048] The routing configuration includes a sending route PdurDestPdur and a receiving route PdurSrcPdur, which are used to associate the PduR module with the CanTp module and the PduR layer with the Dcm module.

[0049] EcuC layer, the EcuC layer is a virtual module, including global protocol data units corresponding to the configuration of each layer.

[0050] In the configuration of ECU, some information needs to be shared among multiple BSWQ modules. Since it is impossible to define who owns the shared information, the virtual module EcuC is introduced.

[0051] The global protocol data units corresponding to the configuration of each layer include global protocol data units associated with the extended frame message.

[0052] The global protocol data unit includes the global protocol data unit Pdu from the Dcm module to the PduR module, the PduR module to the CanTp module, the CanTp module to the CanIf module, the CanIf module to the CanTp module, the CanTp module to the PduR module, and the PduR module to the Dcm module, which associates the protocol data units PDU of each layer. The global PDU in the EcuC module does not need to care about its data type, but only needs to care about the length of the protocol data unit PDU.

[0053] The microcontroller abstraction layer, whose communication driver includes at least 2 first CAN mailboxes for sending and receiving extended frame messages, and a CAN mailbox for sending and receiving standard frame messages, and the microcontroller abstraction layer also includes 2 second CAN mailboxes corresponding to the 2 first CAN mailboxes, which are used to connect the underlying chip with the CAN module. Specifically, the CAN hardware object in the communication driver in the microcontroller abstraction layer includes an extended type EXTENDED and a standard type STANDARD, and the CAN hardware object here is an extended type EXTENDED. The CAN mailbox uses a first-in-first-out mode to receive messages.

[0054] The CAN bus in this embodiment can realize the transmission of extended frame messages and standard frame messages at the same time.

[0055] Example 2

[0056] This embodiment provides a configuration method for a CAN bus that transmits standard frame messages and extended frame messages at the same time. The configuration method is applicable to the CAN bus that transmits standard frame messages and extended frame messages at the same time as described in Embodiment 1. Figure 2 As shown, the steps include:

[0057] S1. Configure the communication driver in the microcontroller abstraction layer, such as Figure 3 shown.

[0058] Specifically, add 2 first CAN mailboxes to the original CAN mailbox

[0059] CANNODE_0_Tx_Std_MailBox_2 and CANNODE_0_Rx_Std_MailBox_2, CanIdType is set to EXTENDED.

[0060] Furthermore, the CAN hardware object in the communication driver in the microcontroller abstraction layer includes an extended type EXTENDED and a standard type STANDARD, and the CAN hardware object here is set to the extended type EXTENDED.

[0061] S2. Configure the CanIf layer to associate the CanIf module with the CanTp module and the Canif module with the CAN driver module, such as Figure 4 shown.

[0062] The CanIf layer is used to assign CAN messages to CAN interfaces according to the CAN bus cluster and CAN ID in the description file of the CAN message, and to create and configure parameter containers of the receiving protocol data unit and the sending protocol data unit. The parameter container configuration content of the receiving protocol data unit includes: CAN ID, data length, message receiving node and response sequence number, and the parameter container configuration content of the sending protocol data unit includes: CAN ID, data length, message sending node and response sequence number.

[0063] Specifically, the sub-items CanIfBufferCfg and CanIfInitHohCfg of CanIfInitCfg match the 2-way CAN mailbox of the CAN driver layer. In the sub-items of CanIfRxPduCfg and CanIfTxPduCfg, configure the CAN communication messages Diag_FOTA_request_CANNODE_0 and Diag_FOTA_response_CANNODE_0 related to the control function.

[0064] Further, CanIfRxPduCanId is set to the CAN extended frame message ID, that is, the identifier of the CAN interface for receiving the CAN L-pdu, and CanIfRxPduCanIdType is set to EXTENDED_CAN, that is, the identifier of the CAN receiving CAN L-PDU, which is received by the CAN driver.

[0065] Furthermore, CAN L-PDU and EXTENDED_CAN represent CAN extended frame messages, CAN L-PDU is associated with Diag_FOTA_request_CANNODE_0_CanIf2CanTp, and EXTENDED_CAN is associated with Diag_FOTA_response_CANNODE_0_CanTp2CanIf.

[0066] Among them, the CAN message includes an extended frame message and a standard frame message, which is a communication message related to the control function. The frame structure of the standard frame consists of a start bit SOF, a frame type RTR or IDE, a frame identifier ID and data Data. The start bit identifies the beginning of a new CAN frame, the frame type field contains a remote transmission request RTR and an identifier extension bit IDE, and the frame identifier contains a unique identifier of the frame, which is used to distinguish different CAN frames. The data field contains the actual transmitted data. The frame structure of the extended frame also consists of a start bit SOF, a frame type RTR, IDE, an extended identifier SID and data Data. The frame identifier of the extended frame is called an extended identifier SID, which is a 29-bit field used to provide a larger address space.

[0067] S3. Configure the CanTp layer to associate the CanIf module with the CanTp module and the CanTf module with the PDURC module, such as Figure 5 shown.

[0068] The CanTp layer includes a channel used only for standard frame messages and a channel used only for extended frame messages, as well as corresponding configurations of receiving service data units and sending service data units. The configurations of receiving service data units and sending service data units include parameters CanTpBs, CanTpNar, CanTpNbr, CanTpNcr, CanTpSTmin, CanTpRxTaType and CanTpRxPaddingActivation.

[0069] Specifically, a channel CanTpChannel_Ext is added solely for extended frames.

[0070] Add the following to the sub-item of CanTpRxNSdu:

[0071] Diag_FOTA_request_CANNODE_0_CanIf2CanTp and

[0072] Diag_FOTA_response_CANNODE_0_CanTp2CanIf associated with Diag_FOTA_request_CANNODE_0_CanTp2PduR;

[0073] Add the following to the sub-item of CanTpTxNSdu:

[0074] Diag_FOTA_request_CANNODE_0_CanIf2CanTp and

[0075] Diag_FOTA_response_CANNODE_0_CanTp2CanIf associated Diag_FOTA_response_CANNODE_0_PduR 2CanTp.

[0076] S4. Configure the PduR layer to associate the PduR module with the CanTp module and the PduR layer with the Dcm module, such as Figure 6 shown.

[0077] The PduR layer includes a routing table, which is provided with routing configurations for the standard frame message and the extended frame message, and the routing configurations include receiving routing and sending routing.

[0078] Specifically, add PduRRoutingPath in PduRRoutingTables: Diag_FOTA_request_CANNODE_0_CanTp2PduR, Diag_FOTA_response_CANNODE_0_Dcm2CanTp

[0079] Furthermore, Diag_FOTA_request_CANNODE_0_CanTp2PduR and Diag_FOTA_request_CANNODE_0_CanTp2PduR and

[0080] Diag_FOTA_request_CANNODE_0_PduR2Dcm association.

[0081] Diag_FOTA_response_CANNODE_0_Dcm2CanTp and

[0082] Diag_FOTA_response_CANNODE_0_Dcm2PduR and

[0083] Diag_FOTA_response_CANNODE_0_PduR2CanTp associated.

[0084] S5. Configure the EcuC layer, such as Figure 7 shown.

[0085] The EcuC layer is a virtual module, including global protocol data units corresponding to the configuration of each layer. In the configuration of the ECU, some information needs to be shared between multiple BSWQ modules. Since it is impossible to define who owns the shared information, the virtual module EcuC is introduced.

[0086] The global protocol data unit corresponding to each layer configuration includes a global protocol data unit associated with the extended frame message, including the global protocol data unit Pdu from the Dcm module to the PduR module, the PduR module to the CanTp module, the CanTp module to the CanIf module, the CanIf module to the CanTp module, the CanTp module to the PduR module, and the PduR module to the Dcm module, which associates the protocol data units PDU of each layer. The global PDU in the EcuC module does not need to care about its data type, but only needs to care about the length of the protocol data unit PDU.

[0087] Specifically, add the following configuration to the PduR sub-item:

[0088] Diag_FOTA_response_CANNODE_0_Phys_Dcm2PduR, Diag_FOTA_response_CANNODE_0_Phys_PduR2CanTp, Diag_FOTA_response_CANNODE_0_Phys_Can Tp2CanIf, Diag_FOTA_request_CANNODE_0_CanIf2CanTp, Diag_FOTA_request_CANNODE_0_CanTp2PduR, Diag_FOTA_request_CANNODE_0_PduR2Dcm.

[0089] S6. Configure the microcontroller abstraction layer again, such as Figure 8 shown.

[0090] Add 2 second CAN mailboxes to the original CAN mailboxes to connect the underlying chip with the CAN module.

[0091] This embodiment can configure a CAN bus that can simultaneously transmit standard frame messages and extended frame messages.

[0092] Example 3

[0093] The present application also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored, and the program is executed by a processor to implement the corresponding function. The computer-readable storage medium of this embodiment implements the configuration method of the CAN bus for simultaneously transmitting standard frame messages and extended frame messages described in Example 2 when executed by a processor.

[0094] Example 4

[0095] The present embodiment provides a computer device, such as a smart phone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server, etc. that can execute a program. The computer device of the present embodiment includes at least but is not limited to: a memory and a processor that can communicate with each other through a system bus. The computer device of the present embodiment executes the configuration method of the CAN bus for simultaneously transmitting standard frame messages and extended frame messages described in Example 2.

[0096] Example 5

[0097] This embodiment provides a detachable vehicle controller, which is equipped with the CAN bus in Embodiment 1 for simultaneously transmitting standard frame messages and extended frame messages, and is adaptable to a variety of vehicle models, including passenger cars and commercial vehicles.

[0098] After receiving the message data, the controller identifies the frame type of the message, determines whether the message belongs to a standard frame or an extended frame, and selects the corresponding transmission path in the CAN bus to complete the transmission of the message.

[0099] In summary, the present invention proposes a CAN bus and a configuration method for simultaneously transmitting standard frame messages and extended frame messages. The CAN bus includes a CAN mailbox for sending and receiving extended frame messages and a transmission path for sending and receiving standard frame messages, thereby realizing the function of simultaneously transmitting standard frames and extended frame messages on one CAN line, and solving the problem that controllers of commercial vehicles and passenger cars cannot be reused due to the single type of CAN messages transmitted by the CAN bus.

[0100] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0101] The order of execution of each step in the above embodiment does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0102] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A CAN bus for simultaneously transmitting standard frame messages and extended frame messages, characterized in that: include: The CanIf layer is used to assign CAN messages to CAN interfaces according to the CAN bus cluster and CAN ID in the description file of the CAN message, and to create and configure the parameter containers of the receive protocol data unit and the send protocol data unit; The CanTp layer includes channels used only for standard frame messages and channels used only for extended frame messages, as well as the corresponding configurations of receiving service data units and sending service data units; The PduR layer includes a routing table, wherein the routing table is provided with routing configurations for the standard frame message and the extended frame message; EcuC layer, the EcuC layer is a virtual module, including global protocol data units corresponding to the configuration of each layer; A microcontroller abstraction layer, whose communication driver includes at least two first CAN mailboxes for sending and receiving extended frame messages, and a first CAN mailbox for sending and receiving standard frame messages, and the microcontroller abstraction layer also includes a second CAN mailbox corresponding to the first CAN mailbox.

2. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 1, characterized in that: The CAN messages include extended frame messages and standard frame messages, and are related to control functions.

3. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 1, characterized in that: The parameter container configuration content of the receiving protocol data unit includes: CAN ID, data length, message receiving node and response sequence number; the parameter container configuration content of the sending protocol data unit includes: CAN ID, data length, message sending node and response sequence number.

4. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 2, characterized in that: The CAN ID of the parameter container of the received protocol data unit is the CAN extended frame message ID.

5. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 1, characterized in that: The configuration of receiving the service data unit and sending the service data unit includes parameters CanTpBs, CanTpNar, CanTpNbr, CanTpNcr, CanTpSTmin, CanTpRxTaType and CanTpRxPaddingActivation.

6. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 1, characterized in that: The global protocol data units corresponding to the configuration of each layer include global protocol data units associated with the extended frame message.

7. The CAN bus for simultaneously transmitting standard frame messages and extended frame messages according to claim 1, characterized in that: The CAN hardware object in the communication driver in the microcontroller abstraction layer is of an extended type.

8. A method for configuring a CAN bus for simultaneously transmitting standard frame messages and extended frame messages, characterized in that: include: Configure the communication driver of the microcontroller abstraction layer, and add at least two first CAN mailboxes for sending and receiving extended frame messages; In the CanIf layer, CAN messages are assigned to CAN interfaces according to the CAN bus cluster and CAN ID in the description file of the CAN message, and parameter containers of the receive protocol data unit and the send protocol data unit are created and configured; In the CanTp layer, add a channel only for extended frame messages, and add the configuration of receiving service data units and sending service data units; At the PduR layer, adding routing configuration for the standard frame message and the extended frame message; In the virtual module EcuC layer, a global protocol data unit corresponding to the configuration added in each layer is added; The microcontroller abstraction layer is configured again, and two second CAN mailboxes corresponding to the two first CAN mailboxes are added.

9. A computer storage medium, characterized in that: A computer program executable by a processor is stored therein, and the computer program executes the configuration method of a CAN bus for simultaneously transmitting standard frame messages and extended frame messages as described in claim 8.

10. A computer device, characterized in that: The computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the computer device executes the configuration method of the CAN bus for simultaneously transmitting standard frame messages and extended frame messages as described in claim 8.

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