JP2008160574A - Data relay device - Google Patents

Abstract

In a data relay device that is provided between a plurality of multiplex communication lines for transmitting data and relays a plurality of types of data, even if a connection destination bus of a communication node is changed, a routing table Avoid rewriting work.
In a multiplex communication system, a data relay device includes a routing table that records data IDs, transmission source channel information, and transmission destination buses in association with each other. The data relay apparatus 10 receives a data frame to which a data ID for specifying the data frame content is added from an arbitrary bus, and adds transmission source channel information for identifying the transmission source bus to the data frame. The data frame is held in the main buffer 15. Then, the destination bus is specified by referring to the routing table 17, and the data frame held in the main buffer 15 is transmitted to this bus.
[Selection] Figure 2

Description

  The present invention relates to a data relay apparatus that is interposed between a plurality of multiplex communication lines that transmit data and relays a plurality of types of data.

  2. Description of the Related Art Conventionally, for example, data relay apparatuses that relay data by being interposed between a plurality of buses (multiplex communication lines) that perform data transmission using a communication protocol that does not specify a destination communication node such as CAN are widely known. ing. In such a data relay device, when receiving data, the routing table in which the data contents and the destination bus are associated is referred to, the destination bus is specified based on the routing table, and the specified destination is specified. One having a function of transferring received data only to a bus is known (for example, see Patent Document 1).

  In particular, as such a data relay device, between each communication node, a transmission source communication node and a unique ID for specifying data contents are attached to the data, and data transmission is performed. A device that identifies a destination bus by referring to a routing table associated with the destination bus has also been developed.

  Here, for example, a routing table as shown in FIG. 9 is used as a routing table used in a data relay apparatus that relays data using an ID. However, in FIG. 9, data is transmitted to the bus labeled “1”, and data is not transmitted to the bus labeled “0”.

  That is, according to this routing table, for example, for data with ID 004, it can be seen that the transmission source bus is Bus1 and the transmission destination buses are Bus2 and Bus3. That is, when the data relay device relays data with ID 004, the data can be received at the communication nodes connected to Bus2 and Bus3.

Further, regardless of whether or not the data relay device relays data, the communication node connected to Bus 1 that is the transmission source bus can also receive this data.
JP 2006-287739 A

By the way, in a communication system to which the data relay device is connected, a design change such as changing a bus (connection destination bus) connecting a certain communication node can often occur.
In such a case, the data relay device only includes a routing table for specifying the transmission destination bus with respect to the ID, so that data can be relayed to a bus that requires data. There is a problem of disappearing.

  Specifically, referring to FIG. 9, when the connection destination bus of the transmission source communication node is set to Bus1 as described above, the data whose ID is 004 is Bus1, Bus2, and Bus3. A communication node connected to can receive data. However, assuming that the connection destination bus of the transmission source communication node is changed to Bus2, Bus1 is not specified as the transmission destination bus in the routing table, and therefore the communication node connected to Bus1 does not have this transmission source communication node. Data cannot be received.

  For this reason, in the data relay device, when the connection destination bus of the communication node is changed, it is necessary to rewrite the routing table each time, which is complicated.

  Therefore, in view of such a problem, in a data relay device that relays a plurality of types of data that is interposed between a plurality of multiplex communication lines that transmit data, the connection destination bus of the communication node is changed. Even if it exists, it is an object of the present invention to prevent the routing table from being rewritten.

  The data relay device according to claim 1, wherein the adding means receives the data to which the specific information for specifying the data content is added, and sends the received data to the transmission source. The identification information for identifying the multiple communication line is added, and the data with the identification information added is held in the main buffer. Then, the transmission means identifies the multiplex communication line of the transmission destination in the data held in the main buffer by referring to the routing table in which the identification information and the identification information and the multiplex communication line of the transmission destination are recorded in association with each other, The data held in the main buffer is transmitted to the specified destination multiple communication line.

  That is, in the present invention, data is written in the routing table referred to by the transmission means so that when both the specific information and the identification information are specified, the destination multiple communication line is specified. Therefore, according to such a data relay device, even if the multiplex communication line connected to the transmission source communication node (data transmission source device) is changed, the routing table corresponds to the identification information after the change. If data specifying the multiplex communication line of the relay destination is written, the data can be favorably relayed without rewriting the routing table.

Note that the routing table in the present invention may be stored in advance in recording means provided in an arbitrary apparatus.
By the way, the data relay device according to claim 1 is provided with a reception buffer for temporarily storing data received via the multiplex communication line of the transmission source as described in claim 2, and the adding means includes the reception buffer. The identification information may be added to the data held in the data, and the data with the identification information added may be held in the main buffer.

  According to such a data relay device, data can be temporarily stored in the reception buffer, so that the processing executed by the adding means and the transmitting means can be given a margin. Therefore, it is possible to prevent the data to be relayed from being discarded due to the process not catching up.

  Furthermore, in the data relay apparatus according to claim 1 or 2, the transmission means deletes the added identification information before transmitting it to the destination multiplex communication line as described in claim 3. It may be.

According to such a data relay device, data unnecessary for communication is deleted, so the communication load on the multiplex communication line can be reduced.
Further, in the data relay device according to any one of claims 1 to 3, when the identification information is an ID that identifies the data node and the communication node that transmitted the data, In the routing table, the ID and identification information and the multiplex communication line of the transmission destination may be recorded in association with each other.

According to such a data relay device, the transmission source communication node can be specified by the ID.
Further, in the routing table of the conventional apparatus, only one routing (the destination multiple communication line corresponding to the ID) can be written for one ID, but in the data relay apparatus of the present invention, 1 By associating a plurality of identification information with one ID, a plurality of routings can be written to the routing table for one ID.

  Therefore, according to such a data relay apparatus, even when the multiplex communication line of the transmission destination is specified by the ID and the multiplex communication line connecting the communication node of the transmission source is changed, the routing table The rewriting work can be made unnecessary.

Embodiments according to the present invention will be described below with reference to the drawings.
[Configuration of Data Relay Device 1]
1 and 2 are schematic diagrams of a multiplex communication system 1 including a data relay device 10 of the present invention.

  The multiplex communication system 1 described in the present embodiment is used for data exchange between automobile control devices. As shown in FIGS. 1 and 2, a plurality of communication buses (multiplexing referred to in the present invention) is used. A communication line, hereinafter simply referred to as “bus”), a plurality of control devices connected to each bus (Bus1, Bus2, Bus3,..., Busn (n is an arbitrary natural number)), and the data relay device 10 It is prepared for.

  As shown in FIG. 1, the plurality of control devices include an engine ECU (electronic control device) 31 that controls the fuel injection amount, ignition timing, and the like, a brake ECU 32 that controls the brake, a transmission ECU 33 that performs shift control, and an air conditioner. An air conditioner ECU 43 for controlling the apparatus is provided. These control devices are connected to a preset bus.

In FIG. 2, only the communication node 40 provided in each control device is displayed. Each bus is connected to the data relay device 10.
In the multiplex communication system 1, the data relay device 10 relays data transmitted from a certain communication node 40 to a communication node 40 connected to another bus as necessary.

  Here, the exchange of data between the communication nodes 40 is performed by the communication nodes 40 transmitting and receiving data using a predetermined protocol. In the present embodiment, each communication node 40 performs communication using, for example, a well-known CAN (Controller Area Network) protocol.

  In this communication protocol, each communication node 40 transmits data (data frame) in a format as shown in FIG. That is, each communication node 40 adds the content of communication data (here, the transmission source communication node 40 and the communication data) to desired communication data (data portion) required by another control device when performing communication. A data frame to which a data ID (identifier, specific information referred to in the present invention) for specifying (type) is added is generated and transmitted.

  Next, as shown in FIG. 2, the data relay apparatus 1 includes a control microcomputer (not shown), a driver / receiver 11, a reception buffer 13, a main buffer 15, a frame transfer control unit 16, a routing table 17, and a transmission. A buffer 18 is provided. The control microcomputer implements the functions of the communication control unit 12, the transmission source channel information processing unit 14, and the frame transfer control unit 16 in FIG. 2 as software processing.

  Note that at least a part of the functions as the communication control unit 12, the transmission source channel information processing unit 14, and the frame transfer control unit 16 may be realized by hardware such as a communication IC, for example. As described above, when at least a part of the functions as the communication control unit 12, the transmission source channel information processing unit 14, and the frame transfer control unit 16 are configured by hardware, a storage process (FIG. 4) described later, At least a part of the routing process (FIG. 5) and the transmission process (FIG. 7) is replaced with this hardware process.

  In FIG. 2, each bus (Bus 1 to Busn), driver / receiver 11, communication control unit 12, and transmission source channel information processing unit 14 are described two by two in order to clarify the data flow. Actually, it is only necessary to provide one by one.

  Furthermore, the driver / receiver 11, the reception buffer 13, and the transmission buffer 18 are provided with a storage area corresponding to the number of connected buses in a one-to-one correspondence. That is, in the present embodiment, since n buses are connected to the data relay device 1, the storage areas in the driver / receiver 11, the reception buffer 13, and the transmission buffer 18 correspond to n buses. It means that n pieces are provided.

  In addition, the reception buffer 13 and the transmission buffer 18 are not guaranteed to be transferred immediately even if the data frame is stored in the transmission buffer 18, so that a buffer capacity sufficient to store a plurality of data frames is secured. Note that the buffer capacity in the driver / receiver 11 is smaller than the buffer capacity in the reception buffer 13 and the transmission buffer 18 as long as the minimum capacity is ensured according to the communication speed in each bus. Good.

  Here, the process of storing the data frame received using the functions of the communication control unit 12 and the transmission source channel information processing unit in the main buffer 15 will be described with reference to FIG. FIG. 4 is a flowchart showing the storing process executed by the control microcomputer.

  The storage process is a process that is started when, for example, an ignition switch (not shown) in the vehicle is turned on. First, a data frame is received from any communication node 40 (any bus). It is determined whether or not (S110). If no data frame has been received (S110: No), the process of S110 is repeated.

  If a data frame has been received (S110: Yes), the data frame is stored in the memory of the driver / receiver 11 of the data relay apparatus 10 (S120). In this process, the driver / receiver 11 is assigned a channel (CH) number (CH1 for Bus1, CH2 for Bus2, CHn for Busn) corresponding to the connected bus, and a data frame is transmitted. The data frame is stored in a storage area corresponding to the incoming bus.

  Subsequently, the data frame in the memory of the driver / receiver 11 is stored in the memory of the reception buffer 13 (S130). Also in this process, the data frame is stored in the storage area (RxBuf1, RxBuf2,..., RxBufn) of the reception buffer 13 corresponding to each bus (channel number) from which the data frame has been transmitted.

  Next, transmission source channel information (identification information referred to in the present invention) is added to the data frame received by the reception buffer 13 (S140: addition means referred to in the present invention). Immediately before the execution of this process, the same data frame as that when the data frame is received by the data relay device 10 (consisting of the data ID and the data part shown in FIG. 3A) is stored in the reception buffer 13. In this process, transmission source channel information is added to this data frame.

  In this process, transmission source channel information may be added after the data portion (see FIG. 3B), or transmission source channel information may be added before the data ID (FIG. 3 (FIG. 3). c)). Further, the source channel information can be added to an arbitrary position such as between the data ID and the data portion as long as it can be read.

  Here, as the transmission source channel information, data corresponding to the channel number assigned to the driver / receiver 11 is added. Therefore, the data frame to which the transmission source channel information is added can identify the data frame transmitted from which bus by referring to the transmission source channel information in the data. .

  Subsequently, the data frame to which the transmission source channel information is added is stored in the memory of the main buffer 15 (S150), and the storage process is terminated. Note that the memory of the main buffer 15 is not divided into storage areas for each channel number, and is configured as a well-known FIFO-type memory that can store a large number of data frames. ing.

  Next, FIG. 5 is used to explain the process of transferring the data frame stored in the main buffer 15 to the transmission buffer corresponding to the transmission destination bus using the functions of the frame transfer control unit 16 and the transmission source channel information processing unit 14. I will explain. FIG. 5 is a flowchart showing a routing process executed by the control microcomputer. Note that this routing processing and transmission processing described later correspond to transmission means in the present invention.

  This routing process is a process that is started, for example, when an ignition switch in the vehicle is turned on, and is performed independently of the transmission process described above. Specifically, first, it is determined whether or not a data frame is stored in the main buffer 15 (S210). If no data frame is stored in the main buffer 15 (S210), the routing process is repeated from the beginning.

  Further, if a data frame is stored in the main buffer 15 (S210: Yes), the data ID and transmission of the data frame that has passed the longest time since the data frame stored in the main buffer 15 is received. The original channel information is read, and the read information is compared with the routing table 17 (S220).

Here, the routing table 17 will be described with reference to FIG. FIG. 6 is an explanatory diagram showing the routing table of this embodiment.
In the routing table 17 in this embodiment, as shown in FIG. 6, a plurality of different transmission source channel numbers are recorded in association with each of the data IDs, and transmission is performed for each of the plurality of transmission source channel numbers. The destination channel number (synonymous with the destination bus) is recorded. That is, according to the routing table 17, by specifying the data ID and the transmission source channel number, a process (routing) for specifying a different transmission destination channel number can be performed.

  Therefore, according to the routing table 17, even if the data ID is the same, different routing can be performed if the transmission source bus (transmission source channel number) is different.

  In the example shown in FIG. 6, the transmission destination channel number corresponding to the transmission destination bus to which the data frame needs to be transferred is described as “1” and corresponds to the transmission destination bus that does not need to transfer the data frame. The transmission destination channel number to be transmitted is described as “0”. Therefore, if “0” is written in all the transmission destination channel numbers, this means that it is not necessary to transfer this data frame to another bus.

  The routing table 17 is recorded in a predetermined memory in the data relay device 10. Specifically, the description content of the routing table 17 will be described. For example, the transmission source channel numbers “CH1”, “CH2”, “CH3”,..., “CHn” are associated with the data ID “002”. In the transmission source channel number “CH1”, the transmission destination channel number “CH1” is set to “0”, and the transmission destination channel numbers “CH2” and “CH3” are set to “1”.

  In the transmission source channel number “CH2”, the transmission destination channel numbers “CH1” and “CH2” are set to “0”, and the transmission destination channel number “CH3” is set to “1”. Further, in the transmission source channel number “CH3”, the transmission destination channel numbers “CH1” and “CH3” are set to “0”, and the transmission destination channel number “CH2” is set to “1”.

  Subsequently, returning to FIG. 5, it is determined whether or not this data frame needs to be transferred to any bus (S230). If it is necessary to transfer the data frame to any of the buses (S230: Yes), this data frame is read from the main buffer 15 (S240), the source channel information is deleted from the data frame, and specified by the routing table This data frame is transferred to the storage area of the transmission buffer corresponding to the transmission destination channel number (S250). Thus, when the process of S250 is completed, the routing process is repeated from the beginning.

  On the other hand, if it is not necessary to transfer the data frame to any bus at S230 (S230: No), the process of transferring this data frame is interrupted (stopped) (S260), and the routing process is repeated from the beginning.

  Next, a process of transmitting a data frame from the main buffer 15 to a predetermined bus using the function of the communication control unit 12 will be described with reference to FIG. FIG. 7 is a flowchart showing a transmission process executed by the control microcomputer.

  The transmission process is a process that is started when, for example, an ignition switch in the vehicle is turned on, and is performed independently of the transmission process and the routing process described above. Specifically, first, it is determined whether or not a data frame has been transferred to the transmission buffer 18.

  If there is no data frame transfer (S310: No), the process of S310 is repeated. If there is a data frame transfer (S310: Yes), the transferred data frame is stored in a predetermined storage area of the transmission buffer 18 (S320). Here, the storage area (TxBuf1, TxBuf2,..., TxBufn) of the transmission buffer 18 is set for each bus (channel number) that transmits a data frame. In this process, the channel number set in the routing process is set. A data frame is stored in a storage area corresponding to.

  Subsequently, the data frame stored in the transmission buffer 18 is stored in the memory of the driver / receiver 11 (S330). Then, the data frame is transmitted from the driver / receiver 11 (S340), and the transmission process is repeated from the beginning.

  When the data frame is transmitted to the driver / receiver 11, the communication node 40 connected to the bus to which the data frame is transmitted can receive the data frame.

[Example of operation of data relay device 1]
Next, an operation example of the data relay device 10 will be described more specifically. Here, an operation example of the data relay apparatus 10 when relaying a data frame from CH2 to CH3 of the driver / receiver 11 (that is, when relaying a data frame from Bus2 to Bus3) will be described.

  First, when a data frame is transmitted from the communication node 40 on the Bus 2, the data relay apparatus 10 uses the function as the communication control unit 12 to convert the data frame transmitted from the communication node 40 on the Bus 2 to a driver / receiver. 11 is stored in RxBuf2 of the reception buffer 13 via CH2. Then, the data relay device 10 uses the function as the transmission source channel information processing unit 14 to add transmission source channel information (here, CH2) to the data frame stored in RxBuf2 of the reception buffer 13, and this data frame Is stored in the main buffer 15.

  Furthermore, the data relay apparatus 10 uses the function as the frame transfer control unit 16 to obtain the data ID (here, “002”, for example) of the data frame stored in the main buffer 15 and the transmission source channel information. By comparing with the contents of the routing table, the destination channel number corresponding to the destination bus of the data frame is determined.

  Here, referring to the routing table 17 shown in FIG. 6 based on the data ID “002” and the transmission source channel number “CH2”, the data frame stored in the main buffer is a data frame to be transmitted to CH3. I understand that. Therefore, this data frame is transferred to TxBuf3 of the transmission buffer 18, but the transmission source channel information is deleted using the function as the transmission source channel information processing unit 14 prior to this transfer.

  Then, after transferring the data frame to TxBuf3 of the transmission buffer 18, the data relay apparatus 10 uses the function as the communication control unit 12 to transfer the data frame stored in TxBuf3 of the transmission buffer 18 to CH3 of the driver / receiver 11. To Bus3.

By such an operation, the data node can be received by the communication node 40 connected to Bus2 and Bus3.
Here, processing when the communication node 40 is disconnected from the Bus 2 and connected to the Bus 3 will be described. When the data relay device 10 receives the data frame from the communication node 40 on the Bus 3, the data relay device 10 transfers the data frame in the order of CH3 of the driver / receiver 11 and RxBuf3 of the reception buffer 13, and adds the source channel information (CH3). The frame is stored in the main buffer 15.

  Then, the data relay device 10 identifies the destination bus by referring to the routing table 17. That is, referring to the routing table 17 shown in FIG. 6 based on the data ID “002” and the transmission source channel number “CH3”, the data frame stored in the main buffer is a data frame to be transmitted to CH2. I understand. Therefore, this data frame is transferred to TxBuf2 of the transmission buffer 18.

  Thereafter, the data relay device 10 transmits the data frame to Bus 2 via CH 2 of the driver / receiver 11. By such an operation, even when the communication node 40 is switched from Bus2 to Bus3, the communication node 40 connected to Bus2 and Bus3 can receive this data frame.

[Effects of data relay device 1]
In the multiplex communication system 1 described in detail above, the data relay apparatus 10 includes a routing table 17 in which a data ID, transmission source channel information, and a transmission destination bus are recorded in association with each other.

  In addition, the data relay device 10 receives a data frame to which a data ID for specifying the data frame content is added from an arbitrary bus in the storage process, and identifies the transmission source bus in the received data frame. Source channel information is added, and this data frame is held in the main buffer 15. Further, the data relay device 10 identifies the destination bus in the data frame held in the main buffer 15 by referring to the routing table 17 in the routing process, and specifies the destination bus identified in the transmission process. On the other hand, the data frame held in the main buffer 15 is transmitted.

  Therefore, according to such a data relay device 10, even if the bus connecting the transmission source communication node 40 (data frame transmission source device) is changed, the transmission source channel information after the change is stored in the routing table 17. If the data frame specifying the relay destination bus is written corresponding to the data frame, the data frame can be relayed well without rewriting the routing table 17.

Moreover, according to such a data relay apparatus 10, the transmission source communication node 40 can be specified by the data ID.
Furthermore, in the routing table of the conventional apparatus (see FIG. 9), only one routing (transmission destination bus corresponding to one data ID) can be written for one data ID. In the routing table 17, it is possible to write a plurality of routings for one data ID by associating a plurality of transmission source channel information with one data ID.

  Therefore, according to such a data relay device 10, even when the destination bus is specified by the data ID and the bus connecting the source communication node 40 is changed, the routing table 17 Rewriting work can be made unnecessary.

  In addition, the data relay device 10 includes a reception buffer 13 that temporarily holds a data frame received via the transmission source bus. Then, the data relay device 10 adds the transmission source channel information to the data frame held in the reception buffer 13 and stores the data frame with the transmission source channel information in the main buffer 15 in the storage process.

  Therefore, according to such a data relay device 10, the data frame can be temporarily stored in the reception buffer 13, so that the processing executed in the storage processing, routing processing, and transmission processing can be given a margin. it can. Therefore, it is possible to prevent the data frame to be relayed from being discarded due to the process not catching up.

Further, the data relay device 10 deletes the added transmission source channel information before it is transmitted to the transmission destination bus in the routing process.
According to such a data relay device 10, data frames unnecessary for communication are deleted, so that the communication load on the bus can be reduced.

[Other Embodiments]
Embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention.

  For example, although the data relay apparatus 1 of the present embodiment is configured to include the reception buffer 13, the storage process, the routing process, and the transmission process can be performed at a sufficiently high speed, or the capacity of the main buffer 15 is sufficient. If there is, it is possible to adopt a configuration in which the reception buffer 13 is not provided as in the data relay device 2 shown in FIG.

  In the present embodiment, the present invention is applied to the multiplex communication system 1 using CAN as a communication protocol. However, even if a communication protocol other than CAN is used, a communication protocol that does not specify the destination communication node 40 is used. The present invention can be applied to any multiplex communication system that performs communication.

  Even if it does in this way, the effect similar to the said embodiment is acquired.

1 is an explanatory diagram schematically showing a multiplex communication system 1. FIG. It is explanatory drawing which shows typically the multiplex communication system 1 (especially the data relay apparatus 10) of embodiment. It is explanatory drawing which shows an example of a data frame structure. It is a flowchart which shows a storage process. It is a flowchart which shows a routing process. It is explanatory drawing which shows the routing table of this embodiment. It is a flowchart which shows a transmission process. It is explanatory drawing which shows typically the multiplex communication system 2 of a modification. It is explanatory drawing which shows the routing table in a conventional apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Multiple communication system, 10 ... Data relay apparatus, 11 ... Driver / receiver, 12 ... Communication control part, 13 ... Reception buffer, 14 ... Transmission source channel information processing part, 15 ... Main buffer, 16 ... Frame transfer control part, 17 ... Routing table, 18 ... Transmission buffer, 40 ... Communication node.

Claims (4)

A data relay device connected to a plurality of multiplex communication lines for transmitting data and outputting each data transmitted to each multiplex communication line to another multiplex communication line,
A main buffer that temporarily holds data received via the source multiplex communication line;
Receiving data to which specific information for specifying data content is added via the transmission source multiplex communication line, adding identification information for identifying the transmission multiplex communication line to the received data, Adding means for holding the data added with the identification information in the main buffer;
The destination information multiplex communication line in the data held in the main buffer is specified by referring to the routing table in which the specific information and the identification information and the destination multiplex communication line are recorded in association with each other. Transmitting means for transmitting the data held in the main buffer to the destination multiplex communication line;
A data relay device comprising: It has a reception buffer that temporarily holds data received via the multiplex communication line of the transmission source,
The adding means adds the identification information to the data held in the reception buffer, and holds the data added with the identification information in the main buffer;
The data relay device according to claim 1. The transmitting means deletes the added identification information before transmitting it to a destination multiplex communication line;
The data relay device according to claim 1, wherein the data relay device is a data relay device. The specific information is an ID for specifying a data node and a communication node that has transmitted the data,
In the routing table, the ID and the identification information are recorded in association with a multiplex communication line of a transmission destination,
The data relay device according to any one of claims 1 to 3.

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