JP2015177365A - Communication node, communication system and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of source IDs attached to a message in a multiplex communication system having a plurality of communication nodes. SOLUTION: One of a plurality of communication nodes mounted on a vehicle and connected to a communication bus is a control for creating a message with an identifier of a source communication node and an identifier of a destination communication node. It has a unit and a transmission unit that transmits a message created by the control unit. When attaching the identifier of the communication node of the source to the message, the control unit communicates with itself in the first area that combines the area with the identifier of the communication node of the source and the additional information area that is not in operation. Attach the identifier of the node. [Selection diagram] Fig. 3

Description

  The present invention relates to a communication system mounted on a vehicle.

  In order to reduce the power consumption when the vehicle stops due to ignition off (IG-OFF), etc., network management (NM: Network Management) is included in the electronic control unit (ECU) that communicates during IG-OFF. ) Some functions are installed. An ECU equipped with a network management function uses a network management message (hereinafter referred to as “NM message”) in order to shift to a power saving mode in cooperation with an ECU equipped with other network management functions on the bus. To determine whether or not the mode can be shifted to the power saving mode.

  There is known a communication control device that transmits data to which an identifier of a data transmission destination is added (see, for example, Patent Document 1).

JP 2000-224260 A

  FIG. 1 shows an example of the format of the NM message. A CAN frame is applied to the NM message. In FIG. 1, (1) shows the format of the entire NM message, and (2) shows the details of a part of the NM message.

  The NM message includes a start of frame (SOF), an arbitration field, a control field, a data field, a CRC field, an ACK field, and an end of frame. (EOF: End of Frame).

  The start of frame indicates the head of the frame and is indicated by a dominant (logic 0) bit. The arbitration field indicates the priority order of frames. A message ID is attached to the arbitration field, the message is identified by this message ID, and the priority of the message is indicated. The message ID may be represented by 11 bits (standard frame) or 29 bits (extended frame).

  The control field is accompanied by a reserved bit and the number of data bytes. The data field is accompanied by various data of 0-8 bytes, a switch signal, a control signal, and the like. The CRC field is used when checking a frame transmission error, and a 15-bit cyclic redundancy check code and a recessive delimiter bit are attached to the CRC field.

  The ACK field is transmitted at the end of the message when the message is correctly received. It is preferable that the receiving side node checks the presence or absence of the ACK bit on the communication bus, and tries again if no ACK is detected. The end of frame indicates the end position of the data frame or the remote frame. The end-of-frame is composed of 7 bits, and all bit levels are “recessive”.

  (2) of FIG. 1 shows the details of the arbitration field and the data field. In the arbitration field and the data field, a header field, an operation field, and a data field are prepared. Further, an ID base and an address field are prepared in the header field, and a source ID (Source ID) and a destination ID (Dest. ID) are attached to the address field. An operation code (Op Code) is attached to the operation field, and data is attached to the data field.

  In the address field of the NM message, 8 bits are prepared to attach the source ID, and the lower 8 bits of the 11 bits of CAN ID are attached to the address field. On the other hand, as the number of ECUs equipped with NM functions increases, it is required to increase the number of source IDs, but at present, the lower 8 bits of CAN ID must be added to the address field so as not to overlap. It is difficult to increase the number of source IDs.

  An object of the present invention is to increase the number of source IDs attached to a message in a multiple communication system having a plurality of communication nodes.

The communication node of one embodiment of the disclosure is
One of a plurality of communication nodes mounted on a vehicle and connected to a communication bus,
A control unit for creating a message attached with an identifier of a communication node of a transmission source and an identifier of a communication node of a transmission destination;
A transmission unit for transmitting the message created by the control unit,
When the control unit appends the identifier of the transmission source communication node to the message, the control unit includes a first region that combines a region that accompanies the identifier of the transmission source communication node and a non-operating additional information region In addition, the identifier of the own communication node is attached.

  According to the disclosed embodiment, the number of source IDs attached to a message can be increased in a multiple communication system having a plurality of communication nodes.

It is a figure which shows an example of a network management message. It is a figure which shows one Example of a communication system. It is a figure which shows one Example (the 1) of a network management message. It is a figure which shows one Example of a 1st communication node. It is a figure which shows an example (the 1) of a source ID offset table. It is a functional block diagram which shows one Example of a 1st communication node. It is a flowchart which shows one Example of operation | movement of a 1st communication node. It is a figure which shows one Example of operation | movement of a communication system. It is a figure which shows an example (the 2) of a source ID offset table. It is a figure which shows one Example (the 2) of a network management message. It is a figure which shows an example of an ID base offset table. It is a figure which shows an example of a communication system. It is a figure which shows the example of application of one Example of a communication system.

Next, the form for implementing this invention is demonstrated, referring drawings based on the following Examples. Examples described below are merely examples, and embodiments to which the present invention is applied are not limited to the following examples.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

<First embodiment>
<Communication system>
FIG. 2 shows an embodiment of a communication system.

  The communication system is mounted on a moving body such as a vehicle. One embodiment of a communication system is mounted on a vehicle, and an event-driven network such as CAN (Controller Area Network) is applied. The communication system can be applied to information LAN, powertrain LAN, body LAN, and the like. Each communication node is realized by a control device such as an electronic control unit (ECU). Moreover, a sensor, an actuator, etc. may be mounted in each communication node.

  The communication system includes a first communication node 100, a second communication node 200, and a third communication node 300. The first communication node 100 to the third communication node 300 are connected by wire through the communication bus 10. Although FIG. 1 shows a case where a communication system is configured by three communication nodes, a communication system may be configured by two communication nodes, or a communication system may be configured by four or more communication nodes. Also good.

  When CAN is applied to the communication system, the communication bus 10 includes two communication lines (CAN bus) having a twisted pair configuration. One of the CAN bus twisted pair lines is a bus called CAN High (hereinafter referred to as CANH) and the other is referred to as CAN Low (hereinafter referred to as CANL). Termination resistors (not shown) are connected to both ends of the communication bus 10. In FIG. 2, CANH and CANL are represented by a single solid line.

  In one embodiment of the communication system, the first communication node 100 transmits a message with the second communication node 200 as a transmission destination, and the second communication node 200 transmits a message with the third communication node 300 as a transmission destination. Then, the third communication node 300 forms a logical link by transmitting a message with the first communication node 100 as a transmission destination.

  The first communication node 100 attaches the ID of its own first communication node 100 to a region (hereinafter referred to as “first region”) that is a combination of the ID base region and the source ID region, and a destination ID region ( (Hereinafter referred to as “second region”) is accompanied by the ID of the second communication node 200 of the transmission destination, and the operation field and the data field are accompanied by information indicating the state of the first communication node 100. Send a message. An example of information representing the state of the first communication node 100 is information representing a state in which activation is continued, information representing a state in which a transition to the power saving mode is possible, and the like.

  The second communication node 200 and the third communication node 300 refer to the destination ID attached to the second area of the NM message transmitted by the first communication node 100, and the destination ID communicates with itself. If it is a node ID, the NM message is processed. Here, since the ID of the second communication node 200 is attached to the second area of the NM message, the second communication node 200 processes the NM message.

  The second communication node 200 acquires information representing the state of the first communication node 100 attached to the NM message, and attaches the ID of the second communication node 200 to the first area of the NM message. In addition, an ID of the third communication node 300 as a transmission destination is attached to the second area, and an NM message attached with information indicating the state of the second communication node 200 in the operation field and the data field is created. Send.

  The third communication node 300 and the first communication node 100 refer to the destination ID attached to the second area of the NM message transmitted by the second communication node 200, and the destination ID communicates with itself. If it is a node ID, the NM message is processed. Here, since the ID of the third communication node 300 is attached to the second area of the NM message, the third communication node 300 processes the NM message.

  The third communication node 300 acquires information representing the state of the second communication node 200 attached to the NM message, and attaches the ID of the third communication node 300 to the first area of the NM message. In addition, an ID of the first communication node 100 as the destination is attached to the second area, and an NM message attached with information indicating the state of the third communication node 300 in the operation field and the data field is generated and transmitted. To do.

  The first communication node 100 and the second communication node 200 refer to the destination ID attached to the second area of the NM message transmitted by the third communication node 300, and the destination ID communicates with itself. If it is a node ID, the NM message is processed. Here, since the ID of the first communication node 100 is attached to the second area of the NM message, the first communication node 100 processes the NM message.

  The first communication node 100 acquires information indicating the state of the third communication node 300 attached to the NM message, and attaches the ID of the first communication node 100 to the first area of the NM message. The NM message with the ID of the second communication node 200 as the destination added to the second area and the information of another communication node attached to the operation field and the data field is created and transmitted. Here, the information on the other communication node is a message notifying that the state of the communication node may be changed after the information indicating the state of the communication node is transmitted through the logical link. By repeating the above operation, whether each of the first communication node 100 to the third communication node 300 to which the communication bus 10 is connected is in a state where the other communication nodes continue to be activated, is in the power saving mode. If all communication nodes can be determined to be able to enter the power saving mode, it is possible to cooperate with all the communication nodes and enter the power saving mode. it can.

<Message format>
FIG. 3 shows an embodiment of a format of a message transmitted by each communication node according to an embodiment of the communication system. A CAN frame is applied to the message. In FIG. 3, (1) shows the format of the entire message, and (2) shows the details of a part of the message.

  The difference is that the conventional message format described with reference to FIG. 1 and the first area, which is a combination of the ID base area and the source ID area, are used as an area associated with the source ID. By using 3 bits of the ID base area as an area for attaching the source ID, the area for attaching the source ID can be expanded from the conventional 8 bits to 11 bits. This can increase the number of source IDs that can be used. In addition, since the area where the source ID is attached to 11 bits can be expanded, the ID of each communication node such as CAN ID can be used as the source ID as it is, and the lower 8 bits of the CAN ID must be attached so as not to overlap. Can be solved.

  On the other hand, since the second area such as the destination ID area is prepared in the data field, it is difficult to expand from 8 bits. Therefore, among the 8 bits of the destination ID area, the upper 2 bits are used as an area for attaching information indicating an offset, and the lower 6 bits are attached with a difference from a value corresponding to the offset (hereinafter referred to as an “offset value”). By making it an area, it represents a CAN ID represented by 11 bits. Here, the offset is an ID that is a starting point set in advance when consecutive IDs are assigned to a plurality of communication nodes. By attaching an offset to the upper 2 bits and attaching a difference from the offset value to the lower 6 bits, it is possible to represent the number of messages (63) represented by 6 bits from any ID corresponding to the offset. it can.

<First communication node 100>
FIG. 4 shows an example of the first communication node 100. FIG. 4 mainly shows the hardware configuration of the first communication node 100. 4 can also be applied to the hardware configuration of the second communication node 200 to the third communication node 300.

  The first communication node 100 includes a communication transceiver 102, a communication circuit 104, a CPU 106, a RAM 108, a ROM 110, and an HD 112, and each is connected via the bus 20.

  The communication transceiver 102 is connected to the communication bus 10, and transmits data from the communication circuit 104 to the communication bus 10 and receives data from the communication bus 10 and inputs the data to the communication circuit 104 under the control of the communication driver. When transmitting data, the communication transceiver 102 sends an inversion signal to CANH and CANL. When receiving data, the communication transceiver 102 determines whether the data on the communication bus 10 is “1” or “0” from the voltage difference between CANH and CANL.

  The communication circuit 104 is connected to the communication transceiver 102 and performs serial communication with other communication nodes via the communication bus 10. The communication circuit 104 transmits data from the CPU 106 from the communication transceiver 102 and inputs data from the communication transceiver 102 to the CPU 106.

  The CPU 106 executes communication processing executed by the communication circuit 104 and processing for controlling the first communication node 100. The CPU 106 is supplied with battery power (+ B power) and an IG (ignition) signal. Further, the CPU 106 controls the operation state of the first communication node 100. The operating state of the first communication node 100 is an activated state (normal state) when the CPU 106 is operating in the normal mode. When the CPU 106 enters the sleep state, power consumption associated with the operation of the CPU 106 is reduced. Since the power supply to the communication circuit 104 is cut off, the power saving mode in which power consumption is low is entered.

  The RAM 108 is used as a work area for the CPU 106. The ROM 110 stores a program used for driving the CPU 106 such as an IPL (Initial Program Loader). Further, the ROM 110 stores a source ID offset table.

  FIG. 5 shows an example of the source ID offset table. The source ID offset table is associated by associating an offset with an offset value. In the example shown in FIG. 5, the offset “0h” (h is a hexadecimal number, the same applies hereinafter), “1h”, “2h”, and “3h” are “360h”, “440h”, “ “570h” and “600h” are associated with each other. FIG. 5 is an example, and the offset may be represented by 2 bits different from FIG. 5, and the offset value may also be represented by 11 bits different from FIG. 5.

  The HD 112 stores various data such as programs for communication nodes.

<Function of the first communication node>
FIG. 6 shows a functional block diagram of the first communication node 100. The functional block diagram of the second communication node 200 and the third communication node 300 can also be applied to FIG.

  The first communication node 100 includes a message processing unit 1062, a state control unit 1064, and a message creation unit 1066. Each of these units is a function or means realized by any one of the constituent elements shown in FIG. 4 operating according to a command from the CPU 106 according to a communication node program expanded from the HD 112 onto the RAM 108. It is.

  Next, each functional configuration of the first communication node 100 will be described in detail. In the following description, in describing each functional configuration of the first communication node 100, main components for realizing each functional configuration of the first communication node 100 among the respective components illustrated in FIG. 4. The relationship with the components will also be described.

  The message processing unit 1062 of the first communication node 100 shown in FIG. 6 is realized by a command from the CPU 106 shown in FIG. 4 and the communication circuit 104 shown in FIG. The message processing unit 1062 receives an NM message transmitted from another communication node from the communication circuit 104 via the communication bus 10. The message processing unit 1062 determines whether the ID of the communication node attached to the second area of the NM message transmitted from another communication node is the ID of the first communication node.

  Since the ID of the destination communication node is attached to the second area in the form of an offset and a deviation from the offset, the message processing unit 1062 represents the information attached to the second area as an offset. Divide into upper 2 bits and lower 6 bits representing deviation. Then, the message processing unit 1062 acquires an offset value (11 bits) corresponding to the upper 2 bits from the source ID offset table (see FIG. 5) stored in the ROM 110, and attaches the offset value to the second area. The lower 6-bit deviation expressed in 11 bits is added to obtain the ID (11 bits) of the destination communication node.

  When the ID of the communication node attached to the second area of the message transmitted from another communication node is the ID of the first communication node, the message processing unit 1062 inputs the message to the message creation unit 1066. At the same time, information indicating the state of the communication node attached to the operation field and data field of the message or information of other communication nodes is acquired and input to the state control unit 1064. On the other hand, when the ID of the communication node attached to the second area of the message transmitted from another communication node is not the ID of the first communication node, the message processing unit 1062 discards the message.

  The state control unit 1064 of the first communication node 100 shown in FIG. 6 is realized by an instruction from the CPU 106 shown in FIG. Information indicating the state of another communication node attached to a message transmitted from another communication node or information of another communication node is input from the message processing unit 1062 to the state control unit 1064. The state control unit 1064 temporarily holds information indicating the state of other communication nodes. Further, the state control unit 1064 controls the state of the first communication node 100 based on the state of the first communication node 100 and information on other communication nodes input from the message processing unit 1062. For example, the state of the first communication node 100 can be shifted to the power saving mode, and information on other communication nodes input from the message processing unit 1062 can also be shifted to the power saving mode. In this case, the state control unit 1064 shifts the first communication node 100 to the power saving mode.

  The message creation unit 1066 of the first communication node 100 shown in FIG. 6 is realized by an instruction from the CPU 106 shown in FIG. A message transmitted from another communication node from the message processing unit 1062 is input to the message creation unit 1066. Message creation unit 1066 creates a message to be transmitted to another communication node. The message creation unit 1066 attaches the ID of the first communication node 100 to the first area of the message input from the message processing unit 1062 and attaches the ID of the communication node of the transmission destination to the second area.

  When attaching the ID of the destination communication node to the second area, the message creation unit 1066 uses the offset value of the source ID offset table (see FIG. 5) stored in the ROM 110 to determine the ID of the destination communication node. A value having the following value and the value closest to the ID of the destination communication node is acquired. Then, the message creation unit 1066 obtains the deviation by expressing the value obtained by subtracting the acquired offset value from the ID of the destination communication node with 6 bits. The message creation unit 1066 attaches an offset (2 bits) and a deviation (6 bits) associated with the offset value acquired in the second ID area.

  Further, the message creation unit 1066 acquires information representing the state of the first communication node 100 from the state control unit 1064, attaches it to the operation field and data field of the message, and inputs them to the communication circuit 104. The message input to the communication circuit 104 is transmitted from the communication transceiver 102 to the communication bus 10.

<Operation of First Communication Node 100>
FIG. 7 shows an example of the operation of the first communication node 100. FIG. 7 can also be applied to the operations of the second communication node 200 and the third communication node 300.

  FIG. 7 illustrates a process in which the first communication node 100 receives an NM message accompanied by another communication node state from another communication node.

  In step S702, the CPU 106 of the first communication node 100 determines whether the ignition is off. When the ignition of the vehicle is turned off, an ignition off signal is input to the CPU 106. The CPU 106 determines whether or not the ignition is off based on whether or not the ignition off signal is input. If the ignition is not off and the ignition is on, the process returns to step S702.

  In step S704, when it is determined in step S702 that the ignition is off, the communication circuit 104 of the first communication node 100 receives a message transmitted from another communication node. When the ignition is off, an NM message is transmitted from another communication node, and the communication circuit 104 receives the NM message.

  In step S706, the message processing unit 1062 of the first communication node 100 determines whether or not the ID of the first communication node 100 is attached to the second region of the message transmitted from the other communication node. . As a result, the first communication node 100 can determine whether or not the message transmitted from another communication node is an NM message with the first communication node 100 as a transmission destination. If the ID of the first communication node 100 is not attached to the second area of the NM message transmitted from another communication node, the message is not a message having the first communication node 100 as a transmission destination, The process returns to S702. When a message transmitted from another message is not a message whose destination is the first communication node 100, the message may be discarded.

  In step S708, when it is determined in step S706 that the NM message transmitted from another communication node is an NM message destined for the first communication node 100, the message processing unit 1062 displays the operation field of the message. , And status information of other communication nodes attached to the data field is acquired, and status information of other communication nodes is input to the status control unit 1064.

  In step S710, the message creation unit 1066 of the first communication node 100 acquires the state information of the first communication node 100 itself.

  In step S712, the message creation unit 1066 attaches the ID of the first communication node 100 to the first area of the NM message transmitted from another communication node.

  In step S714, the message creation unit 1066 attaches the ID of the destination communication node 100 to the second area of the message transmitted from another communication node in the form of an offset and a deviation from the offset.

  In step S716, the message creation unit 1066 attaches the status information of the first communication node 100 acquired from the status control unit 1064 to the operation field and data field of the message transmitted from the other communication node.

  In step S718, the message creation unit 1066 sends to the communication circuit 104 the ID of the first communication node 100 in the source ID area, the ID of the destination communication node 100 in the destination ID area, the operation field, and the data field. A message accompanying the state information of the communication node 100 is input. The communication circuit 104 transmits the message input from the message creation unit 1066 from the communication transceiver 102.

<Example of operation of communication system>
FIG. 8 shows an embodiment of a communication system. In the example illustrated in FIG. 8, the communication system includes a communication node A 400, a communication node B 500, a communication node C 600, and a communication node D 700, and each communication node is connected via the communication bus 10. The logical ring transmitted from the communication node A 400 is transmitted in the order of the communication node B 500, the communication node C 600, and the communication node D 700. The hardware configuration and functional blocks of the communication node A 400, the communication node B 500, the communication node C 600, and the communication node D 700 can be those of the first communication node 100 described above.

  The ID of the communication node A400 is “600h”, the ID of the communication node B500 is “605h”, the ID of the communication node C600 is “580h”, and the ID of the communication node D700 is “395h”. Further, the ROM 110 of each communication node stores a source ID offset table shown in FIG.

  The operation of the communication system will be described.

  The message creation unit 1066 of the communication node A 400 attaches the ID (600h) of the own communication node A 400 to the first area, and attaches the ID (605 h) of the communication node B 500 as the destination to the second area. When the ID (605h) of the destination communication node B 500 is attached to the second area, the message creation unit 1066 attaches 3h (600h) to the upper 2 bits of the second area and adds the lower 6 bits. “000101” (005h) is added. That is, the message creation unit 1066 attaches “11000101” to the second area. Further, the message creation unit 1066 attaches network management information such as the status information of the communication node A 400 to the operation field and the data field, and creates a message.

  Message creation unit 1066 inputs the message to communication circuit 104, and communication circuit 104 transmits the message from communication transceiver 102.

  The message transmitted from communication node A 400 is received by communication node B 500 -communication node D 700. Each of communication node B500-communication node D700 analyzes information attached to the second region attached to the message. The message processing unit 1062 of the communication node B 500 to the communication node D 700 divides information attached to the second area into upper 2 bits and lower 6 bits. The message processing unit 1062 acquires the offset value corresponding to the upper 2 bits from the cell ID offset table stored in the ROM 110, adds the offset value and the lower 6 bits represented by 11 bits, Get the ID of the communication node. Specifically, “11000101” attached to the second area is divided into upper 2 bits “11” and lower 6 bits “000101”. Then, the message processing unit 1062 acquires the offset value “600h” associated with the upper 2 bits “11” from the cell ID offset table (see FIG. 9), and the “600h” and the lower 6 bits are 11 bits. The represented “005h” is added to obtain “605h”. Since the communication node ID “605h” is the communication node B 500, the message processing unit 1062 of the communication node B 500 controls the status information of the communication node attached to the operation field and the data field of the message. The message is input to the unit 1064 and a message is input to the message creation unit 1066. On the other hand, the message processing unit 1062 of the communication node C600 and the communication node D700 discards the message.

  The message creation unit 1066 of the communication node B 500 attaches the ID (605h) of the self-communication node B 500 to the first area, and attaches the ID (580h) of the destination communication node C 600 to the second area. When the ID (580h) of the destination communication node C600 is attached to the second area, the message creation unit 1066 attaches 2h (570h) to the upper 2 bits of the second area and adds the lower 6 bits. “001010” (010h) is attached. That is, the message creation unit 1066 attaches “10001010” to the second area. Further, the message creation unit 1066 attaches network management information to the operation field and the data field, and creates a message.

  Message creation unit 1066 inputs the message to communication circuit 104, and communication circuit 104 transmits the message from communication transceiver 102.

  The message transmitted from the communication node B500 is received by the communication node A400, the communication node C600, and the communication node D700. Each of communication node A 400, communication node C 600, and communication node D 700 analyzes the information attached to the second region attached to the message. The message processing unit 1062 of the communication node A 400, the communication node C 600, and the communication node D 700 divides the information attached to the second area into upper 2 bits and lower 6 bits. The message processing unit 1062 acquires the offset value corresponding to the upper 2 bits from the cell ID offset table stored in the ROM 110, adds the offset value and the lower 6 bits represented by 11 bits, Get the ID of the communication node. Specifically, “10001010” attached to the second area is divided into upper 2 bits “10” and lower 6 bits “001010”. Then, the message processing unit 1062 obtains an offset value “570h” associated with the upper 2 bits “10” from the cell ID offset table (see FIG. 9), and the “570h” and the lower 6 bits are 11 bits. The represented “010h” is added to obtain “580h”. Since the communication node ID “580h” is the communication node C600, the message processing unit 1062 of the communication node C600 inputs the state information of the communication node attached to the data field of the message to the state control unit 1064. At the same time, a message is input to the message creation unit 1066. On the other hand, the message processing unit 1062 of the communication node A 500 and the communication node D 700 discards the message.

  The message creation unit 1066 of the communication node C600 attaches the ID (580h) of the own communication node C600 to the first area, and attaches the ID (395h) of the destination communication node D700 to the second area. When the ID (395h) of the destination communication node D700 is attached to the second area, the message creation unit 1066 attaches 0h (360h) to the upper 2 bits of the second area and also adds the lower 6 bits. “010011” (035h) is attached. That is, the message creation unit 1066 attaches “00010011” to the second area. Further, the message creation unit 1066 attaches network management information to the operation field and the data field, and creates a message.

  Message creation unit 1066 inputs the message to communication circuit 104, and communication circuit 104 transmits the message from communication transceiver 102.

  The message transmitted from the communication node C600 is received by the communication node A400, the communication node B500, and the communication node D700. Each of communication node A 400, communication node B 500, and communication node D 700 analyzes the information attached to the second region attached to the message. The message processing unit 1062 of the communication node A 400, the communication node B 500, and the communication node D 700 divides the information attached to the second area into upper 2 bits and lower 6 bits. The message processing unit 1062 acquires the offset value corresponding to the upper 2 bits from the cell ID offset table stored in the ROM 110, adds the offset value and the lower 6 bits represented by 11 bits, Get the ID of the communication node. Specifically, “00010011” attached to the second area is divided into upper 2 bits “00” and lower 6 bits “010011”. Then, the message processing unit 1062 acquires the offset value “360h” associated with the upper 2 bits “00” from the cell ID offset table (see FIG. 9), and 11 bits of this “360h” and the lower 6 bits. The represented “035h” is added to obtain “395h”. Since the communication node ID is “395h” in the communication node D700, the message processing unit 1062 of the communication node D700 controls the state information of the communication node attached to the operation field and the data field of the message. The message is input to the unit 1064 and a message is input to the message creation unit 1066. On the other hand, the message processing unit 1062 of the communication node A 500 and the communication node B 600 discards the message.

  The message creation unit 1066 of the communication node D700 attaches the ID (395h) of the self-communication node D700 to the first area, and attaches the ID (600h) of the destination communication node A400 to the second area. When attaching the ID (600h) of the destination communication node A 400 to the second area, the message creation unit 1066 attaches 3h (600h) to the upper 2 bits of the second area and adds the lower 6 bits. “000000” (000h) is attached. That is, the message creation unit 1066 attaches “11000000” to the second area. Further, the message creation unit 1066 attaches network management information to the operation field and the data field, and creates a message.

  Message creation unit 1066 inputs the message to communication circuit 104, and communication circuit 104 transmits the message from communication transceiver 102.

  The message transmitted from the communication node D700 is received by the communication node A400, the communication node B500, and the communication node C600. Each of communication node A 400, communication node B 500, and communication node C 600 analyzes information attached to the second region attached to the message. The message processing unit 1062 of the communication node A 400, the communication node B 500, and the communication node C 600 divides the information attached to the second area into upper 2 bits and lower 6 bits. The message processing unit 1062 acquires the offset value corresponding to the upper 2 bits from the offset table stored in the ROM 110, adds the offset value and the lower 6 bits represented by 11 bits, and transmits to the destination communication node Get the ID. Specifically, “11000000” attached to the second area is divided into upper 2 bits “11” and lower 6 bits “000000”. Then, the message processing unit 1062 acquires the offset value “600h” associated with the upper 2 bits “11” from the cell ID offset table (see FIG. 9), and the “600h” and the lower 6 bits are 11 bits. Add "000h" to obtain "600h". Since the communication node ID “600h” is the communication node A 400, the message processing unit 1062 of the communication node A 400 controls the status information of the communication node attached to the operation field and the data field of the message. The message is input to the unit 1064 and a message is input to the message creation unit 1066. On the other hand, the message processing unit 1062 of the communication node B 500 and the communication node C 600 discards the message.

  The communication node A 400 acquires information indicating the state of the communication node D 400 attached to the NM message, attaches the ID of the own communication node A 400 to the first area of the NM message, and sends the destination communication to the second area. An NM message in which the ID of the node B 500 is attached and information on other communication nodes is attached to the operation field and the data field is created and transmitted.

  The processing described above can be applied to subsequent processing.

  According to one embodiment of the communication system, in addition to the 8 bits of the source ID area, an ID base that is not currently used as an area to accompany the message transmitted by the communication node with the ID (identifier) of the source communication node Use 3 bits of the region. Thereby, the number of IDs of the source communication node can be increased. In the past, it was necessary to assign the lower 8 bits of the 11 bits of the communication node ID to the 8 bits of the source ID area so that they do not overlap. By attaching the bit and the first area including the 8 bits of the source ID area, the restriction can be eliminated.

  In addition, when using the 8 bits of the destination ID area as an area for attaching the ID of the destination communication node to the message transmitted by the communication node, the upper 2 bits are assigned to the offset, and the lower 6 bits are assigned. Assign to the deviation from the arbitrary offset assigned to the 2 bits. In this way, by assigning the upper 2 bits to the offset and assigning the lower 6 bits to the deviation, it is possible to specify the number of destination IDs represented by 6 bits from an arbitrary offset value. In other words, even if the amount of information in the area that can accompany the ID (identifier) of the source communication node is expanded, and the amount of information in the area that can accompany the ID (identifier) of the destination communication node is different, Since the ID of the destination communication node is attached in a format different from the ID of the source communication node, it is possible to cope without expanding the area attached with the ID of the destination communication node.

<Second embodiment>
<Communication system>
FIG. 2 can be applied to the communication system according to the second embodiment.

<Message format>
FIG. 10 shows an embodiment of a format of a message transmitted by each communication node according to an embodiment of the communication system. A CAN frame is applied to the message. In FIG. 10, (1) shows the format of the entire message, and (2) shows the details of a part of the message.

  The format of the NM message shown in FIG. 10 is different from the conventional message format described with reference to FIG. 1 in that the value attached to the ID base area is variable. Information attached to the ID base area is determined according to a value attached to the source ID area. Compared with the first embodiment, the lower 8 bits of the CAN ID attached to the source ID area are changed by changing the information attached to the ID base area according to the value attached to the source ID area. Even if it is incidental, the number of source IDs can be increased, so it is possible to cope with the exhaustion of source IDs.

  FIG. 4 can be applied to the hardware configuration of the first communication node 100. However, the ROM 110 stores an ID base offset table.

  FIG. 11 shows an example of the ID base offset table. The ID base offset table is associated by associating the ID base with the range of the source ID corresponding to the ID base. In the example shown in FIG. 11, “00h-40h”, “41h-5Fh”, and “60h-6Fh” are associated with the ID bases “3h”, “4h”, and “5h”, respectively. Are associated with each other. FIG. 11 is an example, and an ID base different from FIG. 11 and a source ID range may be associated with each other, or a different source ID range may be associated with the ID base of FIG. 11. By assigning different ID bases according to the source ID, even if the lower 8 bits of the CAN ID have the same value, the ID base can be made different, so assign the CAN ID with the same lower 8 bits. Can do. Since CAN IDs having the same lower 8 bits can be assigned, the number of usable source IDs can be increased.

  FIG. 6 can be applied to the functional block diagram of the first communication node 100.

  The message processing unit 1062 of the first communication node 100 is realized by a command from the CPU 106 shown in FIG. 4 and the communication circuit 104 shown in FIG. A message transmitted from another communication node from the communication circuit 104 via the communication bus 10 is input to the message processing unit 1062. The message processing unit 1062 determines whether the ID of the communication node attached to the destination ID area of the message transmitted from another communication node is the ID of the first communication node.

  Since the lower 8 bits of the ID of the destination communication node are attached to the destination ID area, the message processing unit 1062 acquires the lower 8 bits of the ID of the destination communication node from the destination ID area.

  When the ID of the communication node attached to the destination ID area of the message transmitted from another communication node is the ID of the first communication node, the message processing unit 1062 inputs the message to the message creating unit 1066. At the same time, information indicating the state of the communication node attached to the data field of the message is acquired and input to the state control unit 1064. On the other hand, when the ID of the communication node attached to the destination ID area of the message transmitted from another communication node is not the ID of the first communication node, the message processing unit 1062 discards the message.

  The state control unit 1064 of the first communication node 100 is realized by a command from the CPU 106 shown in FIG. Information on another communication node attached to a message transmitted from another communication node is input from the message processing unit 1062 to the state control unit 1064. The state control unit 1064 controls the state of the first communication node 100 based on the state of the first communication node 100 and information on other communication nodes input from the message processing unit 1062. For example, the state of the first communication node 100 can be shifted to the power saving mode, and information on other communication nodes input from the message processing unit 1062 can also be shifted to the power saving mode. In this case, the state control unit 1064 shifts the first communication node 100 to the power saving mode.

  The message creation unit 1066 of the first communication node 100 is realized by a command from the CPU 106 shown in FIG. A message transmitted from another communication node from the message processing unit 1062 is input to the message creation unit 1066. Message creation unit 1066 creates a message to be transmitted to another communication node. The message creation unit 1066 attaches the lower 8 bits of the ID of the first communication node 100 to the source ID region of the message input from the message processing unit 1062 and attaches the ID base value to the ID base region. When an ID base value is attached to the ID base area, the message creation unit 1066 associates the ID base offset table (see FIG. 11) stored in the ROM 110 with the lower 8 bits of the ID of the first communication node 100. The obtained ID base value is acquired and attached to the ID base area.

  Further, the message creation unit 1066 acquires information representing the state of the first communication node 100 from the state control unit 1064, attaches it to the data field of the message, and inputs it to the communication circuit 104. The message input to the communication circuit 104 is transmitted from the communication transceiver 102 to the communication bus 10.

  According to an embodiment of the communication system, different values are attached to the ID base area in accordance with the ID (identifier) of the transmission source communication node in the message transmitted by the communication node. Thereby, the number of IDs of the source communication node can be increased. Up to now, it was necessary to assign the lower 8 bits of the 11 bits of the communication node ID to the 8 bits of the source ID area so that they do not overlap, but a different value depending on the ID of the source communication node By attaching to the base region, the restriction can be removed.

<Application example of communication system>
The example which applied the communication system which concerns on the 1st Example mentioned above and the 2nd Example to Partial Network Management (PNM: Partial Network Management) is shown. In normal network management, cooperative control between a state in which activation is continued and a state in which a transition to the power saving mode can be performed is executed in all communication nodes connected to the communication bus. However, partial network management can be performed at some of the communication nodes connected to the communication bus.

  FIG. 12 shows a conventional example of partial network management.

  A communication node A40, a communication node B50, a communication node C60, and a communication node D70 are connected to the communication bus 10. Among the plurality of communication nodes, the communication node A40, the communication node B50, and the communication node C60 constitute a group 1, and the communication node C60 and the communication node D70 constitute a group 2. A case where partial network management is applied to this communication system will be described.

  The communication node D70 is in a state where it can shift to the power saving mode. On the other hand, the communication node C60 belonging to the same group 2 as the communication node D70 transmits the operation field of the NM message and information indicating the state of continuing the activation in the operation field and data field of the NM message in response to a request to continue communication with the communication node B. To do. For this reason, the communication node D70 cannot shift to the power saving mode because the communication node C60 is in a state where the activation continues even though it can shift to the power saving mode. That is, since the communication node C60 belongs to both the group 1 and the group 2, if the communication node A40, the communication node B50, and the communication node C60 that belong to the group 1 do not enter the power saving mode, the communication node C60 The communication node D70 belonging to the same group 2 cannot move to the power saving mode.

  FIG. 13 shows an embodiment of partial network management.

  A communication node A400, a communication node B500, a communication node C600, and a communication node D700 are connected to the communication bus 10. The hardware configuration and functional blocks of the communication node A 400, the communication node B 500, the communication node C 600, and the communication node D 700 can be those of the first communication node 100 described above. Among the plurality of communication nodes, the communication node A 400, the communication node B 500, and the communication node C 600 constitute a group 1, and the communication node C 600 and the communication node D 700 constitute a group 2. A case where partial network management is applied to this communication system will be described.

  In the embodiment described above, since the source ID assigned to each communication node can be increased, the source ID corresponding to the group 1 and the source ID corresponding to the group 2 can be assigned to the communication node C600. When the source ID corresponding to the group 1 and the source ID corresponding to the group 2 are assigned to the communication node C600, the communication node C600 indicates that the NM message transmitted between the communication nodes belonging to the group 1 continues to be activated. The NM message transmitted together with the information to be transmitted and transmitted between the communication nodes belonging to the group 2 can be transmitted with the information representing the state capable of shifting to the power saving mode. In this way, the communication node D700 can shift to the power saving state.

  In the above-described embodiment, the NM message has been described as an example of the message transmitted by each communication node. Applicable to.

  Although the present invention has been described above with reference to specific embodiments, each embodiment is merely an example, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, and the like. I will. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be implemented in hardware, software, or a combination thereof. The present invention is not limited to the above-described embodiments, and various variations, modifications, alternatives, substitutions, and the like are included without departing from the spirit of the present invention.

10 communication bus 100 first communication node 102 communication transceiver 104 communication circuit 106 CPU
108 RAM
110 ROM
112 HD
200 Second communication node 300 Third communication node 400 Communication node A
500 Communication Node B
600 Communication node C
1062 Message processing unit 1064 Status control unit 1066 Message creation unit

Claims (9)

One of a plurality of communication nodes mounted on a vehicle and connected to a communication bus,
A control unit for creating a message attached with an identifier of a communication node of a transmission source and an identifier of a communication node of a transmission destination;
A transmission unit for transmitting the message created by the control unit,
When the control unit appends the identifier of the transmission source communication node to the message, the control unit includes a first region that combines a region that accompanies the identifier of the transmission source communication node and a non-operating additional information region A communication node that accompanies the identifier of its own communication node. The amount of information that can be attached to the first area is different from the amount of information that can be attached to the second area that accompanies the identifier of the destination communication node,
The control unit attaches the identifier of the destination communication node to the second region in a format different from the format in which the identifier of the own communication node is attached to the first region. The listed communication node.   When the controller adds the identifier of the destination communication node to the second area, the control unit represents information indicating an ID of the communication node serving as a starting point and a difference from the ID of the communication node serving as the starting point. The communication node according to claim 2, wherein an identifier of the destination communication node is represented by information. When the ignition of the vehicle is off, the control unit attaches information indicating the state of the communication node to the message,
The communication node according to any one of claims 1 to 3, wherein the transmission unit transmits a message attached with information indicating a state of the communication node by the control unit.   The control unit, based on information representing a state of the other communication node attached to a message transmitted from a communication node other than the own communication node among the plurality of communication nodes, the state of the own communication node The communication node according to claim 4, wherein the communication node is controlled. A communication system mounted on a vehicle and having a plurality of communication nodes connected to a communication bus,
Each of the plurality of communication nodes is
A control unit for creating a message attached with an identifier of a communication node of a transmission source and an identifier of a communication node of a transmission destination;
A transmission unit for transmitting the message created by the control unit,
When the control unit appends the identifier of the transmission source communication node to the message, the control unit includes a first region that combines a region that accompanies the identifier of the transmission source communication node and a non-operating additional information region A communication system that accompanies the identifier of the communication node. The amount of information that can be attached to the first area is different from the amount of information that can be attached to the second area that accompanies the identifier of the destination communication node,
The control unit attaches an identifier of the destination communication node to the second area in a format different from a format in which the identifier of the own communication node is attached to the first area. The communication system described. A communication method mounted on a vehicle and executed by one of a plurality of communication nodes connected to a communication bus,
Create a message with the identifier of the source communication node and the identifier of the destination communication node,
Send the created message,
When the identifier of the transmission source communication node is attached to the message, the local communication node is included in a first area that combines the area where the transmission source communication node identifier is attached and the additional information area that is not operated. A communication method with an identifier. The amount of information that can be attached to the first area is different from the amount of information that can be attached to the second area that accompanies the identifier of the destination communication node,
The communication method according to claim 8, wherein the identifier of the destination communication node is attached to the second area in a format different from the form in which the identifier of the communication node is attached to the first area.

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