JP7247916B2 - Communication device - Google Patents

Description

The present disclosure relates to communication devices.

A technology is known in which a device is connected to a communication line and communicates according to a predetermined communication method (that is, protocol).
For example, Patent Literature 1 below discloses a technique for transmitting data longer than the data length defined by the protocol by dividing the data so that it fits within the data length defined by the protocol and transmitting the data in multiple frames. is proposed.

JP-A-2002-208934

Also, when data is divided to fit within the data length defined by the protocol and transmitted in a plurality of frames, each of the plurality of frames indicates that it contains divided data obtained by dividing one piece of data. There are known techniques for For example, according to ISO 14299, information indicating the order of divided data is attached to the header of each of a plurality of frames, and the frames are transmitted in order. A technique for obtaining data of one of is disclosed.

On the receiving side, reception of one data is completed only after reception of all frames is completed. For example, if part of the data is updated during frame transmission, after all frames have been transmitted, multiple frames containing divided data obtained by dividing the updated data are generated at the next transmission timing. Transmission is started. In other words, it takes time to transmit the updated data, and it is difficult to transmit the updated data promptly.

In one aspect of the present disclosure, when transmitting communication data longer than a data length predetermined in a communication method, when the communication data is updated, the time until the updated communication data is transmitted is To provide a technique for suppressing delay.

One aspect of the present disclosure is at least one communication device (10, 20) among a plurality of communication devices that are connected to a communication line and perform communication according to a predetermined communication method, and includes a transmission execution unit (35) , an update determination unit (36, S10), a transmission determination unit (36, S35), and an untransmitted update unit (36, S40).

The transmission execution unit sequentially acquires and transmits divided frames from a divided storage unit in which a plurality of divided frames are stored. The divided frame is a frame containing each of divided data obtained by dividing communication data whose data length exceeds a preset data length into a plurality of divided data, and new communication data is generated. generated each time The update determination unit determines whether or not the new communication data has been changed when the new communication data is generated.

When the new communication data is determined to have been changed when the new communication data is generated, the transmission determination unit causes the transmission execution unit to transmit the divided frames including the changed part of the new communication data. It is determined whether or not it has been completed. The untransmitted update unit generates an update frame when the transmission execution unit determines that the divided frame including the changed portion has not been transmitted, and updates the untransmitted divided frame including the changed portion stored in the division storage unit. Replace the frame with the update frame. The update frame is a divided frame including an untransmitted changed portion, and is obtained by replacing the pre-update communication data in the changed portion with new communication data.

According to such a configuration, on the receiving side, when all the divided frames are received, reception of new communication data (that is, communication data after update) is completed instead of communication data before update. do. As a result, when transmitting communication data longer than the set data length predetermined in the communication method, new communication data is generated, and if the communication data has been updated, the updated communication data A delay until data is transmitted can be suppressed.

1 is a block diagram showing the configuration of a communication system; FIG. FIG. 2 is a block diagram showing functions of an ECU; Explanatory drawing which shows the frame format of CAN. FIG. 4 is an explanatory diagram showing how previous communication data and new communication data are stored in a large data storage area; FIG. 4 is an explanatory diagram showing the format of the data portion for divided frames when communication data is divided into Q and transmitted with a total data length P; FIG. 4 is an explanatory diagram showing divided frames stored in a divided frame buffer; 4 is a flowchart of update processing; FIG. 4 is an explanatory diagram for explaining how to identify a changed portion between new communication data and communication data before update; Explanatory drawing explaining the effect|action by an update frame. FIG. 10 is an explanatory diagram showing how untransmitted divided frames are discarded when the transmission processing unit determines that the divided frames including the changed portion have already been transmitted.

Hereinafter, embodiments will be described with reference to the drawings.
[1. composition]
A configuration of a communication system 1 to which an ECU 10 according to this embodiment is applied will be described with reference to FIG. A communication system 1 according to this embodiment is a system mounted on a vehicle. The communication system 1 includes an ECU 10 and an ECU 20 . The ECU 10 and the ECU 20 are constituent devices that are connected by a CAN standard communication line 5 to form a vehicle network, that is, nodes of the vehicle network. CAN is a registered trademark.

The ECU 10 is an electronic control unit that controls objects to be controlled mounted in the vehicle, such as an engine and a brake. The ECU 20 is an electronic control device that controls a control target different from that of the ECU 10 . A case where data is exchanged between the ECUs 20, for example, will be described below.

In addition to the ECU 10 and the ECU 20, the vehicle network in the communication system 1 may include various ECUs to be controlled (not shown). The ECU 10, the ECU 20, and various ECUs are communicably connected to each other via a communication line 5, and can serve as nodes of a vehicle network.

A configuration of the ECU 10 will be described with reference to FIG. Since the ECU 20 has the same configuration as the ECU 10, a description thereof will be omitted.
The ECU 10 includes a CPU 12, a semiconductor memory (hereinafter referred to as memory) 13 such as ROM, RAM, etc., a data transmission/reception unit 14, and a microcomputer (hereinafter referred to as microcomputer) 11 including an I/O and a bus. The CPU 12 controls communication with the ECU 20, which is another communication device connected to the communication line 5, by executing a program stored in a non-transitional substantive recording medium such as a semiconductor memory (for example, the memory 13). do. The data transmission/reception unit 14 transmits/receives data via the communication line 5 to/from each device constituting the vehicle network.

The ECU 10 includes an application 31, a divided frame generation unit 32, a communication unit 33, and a communication confirmation unit 36, as shown in FIG.
The application 31 is an application executed on the ECU 10 . As the application 31 is executed by the CPU 12 of the ECU 10, communication data to be transmitted from the ECU 10 via the communication line 5 (for example, to the ECU 20) is generated.

Note that the memory 13 has a large data storage area, which is a predetermined storage area. The large data storage area is an area in which large data is stored, and the large data is data whose data length is longer than the set data length. The set data length is a data length predetermined by the protocol, and is the maximum data length that can be transmitted in one frame based on the protocol. For example, in CAN, the frame format is predetermined as shown in FIG. 3, and the set data length for data is 64 bytes.

The communication data generated by the application 31 of the present embodiment is data whose data length is longer than the set data length (that is, large data). The application 31 stores the generated communication data in the large data storage area of the memory 13 in order of generation.

For example, as shown in FIG. 4, each large data storage area is assigned a storage area number for identifying each storage area. The large data storage area stores communication data t1, communication data t2, . The data length of the communication data in this embodiment is r (that is, r>set data length). Communication data t1 is communication data generated at time t1, and communication data t2 is data generated at time t2 after time t1 (that is, t1<t2).

Hereinafter, communication data newly generated by the application 31 is referred to as new communication data, and communication data generated by the application 31 immediately before new communication data is generated is referred to as previous communication data. That is, in FIG. 4, the communication data t1 corresponds to the previous communication data, and the communication data t2 corresponds to the new communication data.

FIG. 4 shows that the new communication data has at least part of the data changed (that is, does not match) with respect to the previous communication data. The new communication data generated by the application 31 and at least a part of which is changed from the previous communication data is also referred to as post-update communication data. In addition, communication data immediately preceding update communication data is also referred to as pre-update communication data.

Each time the application 31 stores new communication data in the large data storage area, the application 31 may store the storage area number in the memory 13 as the latest area number.
The divided frame generator 32 determines whether or not the application 31 has generated new communication data. For example, the divided frame generation unit 32 may determine that new communication data has been generated by the application 31 when the latest area number has changed.

When determining that new communication data has been generated, the divided frame generation unit 32 first divides the new communication data into data having a set data length or less to generate a plurality of divided data. The divided data refers to data obtained by dividing communication data whose data length is longer than the set data length into a plurality of pieces whose data length is less than the set data length. The division frame generation unit 32 divides the new communication data into a plurality of division data so that the data length becomes a predetermined division length equal to or less than the set data length. In this embodiment, it is assumed that the division length is equal to the set data length.

The divided frame generator 32 then generates a plurality of divided frames. A divided frame is a frame that includes each piece of divided data, and is generated by the divided frame generator 32 each time new communication data is generated by the application 31 . The divided frame according to the present embodiment is configured by inserting a divided frame data portion instead of the normal frame data in the CAN shown in FIG.

Specifically, as shown in FIG. 5, the divided frame data section includes a total data length, a divided data number, and stored data. The total data length is the data length of the entire communication data (that is, the data length of the communication data before division). Here, let the total data length be r.

The total data length is information for recognizing the reconfigured data length when reconfiguring the communication data from the divided data on the receiving side. The divided data number is a serial number indicating the order in which the divided data is divided from the communication data. A serial number is a number assigned in order from the beginning, such as 1, 2, 3, . . . The divided data number is information for recognizing the order of combining the divided data when the receiving side reconstructs the communication data from the divided data.

The stored data includes divided data to be transmitted in divided frames. When transmitting the last divided data among a plurality of divided data representing communication data, the last divided data and the CRC are included as stored data. CRC is an abbreviation for Cyclic Redundancy Code. The CRC referred to here is the CRC for the entire new communication data to be transmitted.

FIG. 5 shows the divided frame data portions obtained by dividing the communication data having the data length r into Q pieces in the order of divided data numbers. In the Q-th, that is, the last data section for the divided frame, the divided data is used as storage data with a CRC added. Note that Q is an integer of 2 or more.

The divided frame generator 32 inserts the above-described divided frame data section as data into the format shown in FIG. 3, calculates the CRC, and generates divided frames. The CRC here is a CRC as a divided frame. That is, the CRC referred to here can be, for example, the CRC for the data from the SOF to immediately before the CRC.

Note that the memory 13 has a divided frame buffer, which is a predetermined storage area. A segmented frame buffer is an area in which segmented frames are stored.
As shown in FIG. 6, the divided frame generation unit 32 stores the generated divided frames in the divided frame buffer in the order in which they were generated. As a result, the divided frame buffer stores a plurality of divided frames representing the generated new communication data in the order in which the new communication data was generated. That is, they are stored in chronological order. It should be noted that each divided frame for representing one piece of communication data is stored in the divided frame buffer in the order of divided data numbers.

The communication unit 33 transmits and receives data via the data transmission/reception unit 14 and the communication line 5 according to a predetermined communication protocol (that is, CAN). The communication unit 33 includes a reception processing unit 34 and a transmission processing unit 35 . The reception processing unit 34 receives data from another device (for example, the ECU 20 ) via the data transmission/reception unit 14 and the communication line 5 , and the received data is used by the application 31 .

When transmitting communication data, which is the execution result of the application 31 , to another device (for example, the ECU 20 ), the transmission processing unit 35 acquires the divided frames from the divided frame buffer and transmits them via the data transmission/reception unit 14 and the communication line 5 . Send multiple times in sequence.

The transmission processing unit 35 increments the transmission count value by one each time the divided frame is transmitted via the data transmission/reception unit 14 and the communication line 5 . The transmission count value indicates a serial number of a divided frame that has already been transmitted among a plurality of divided frames for representing communication data. The transmission count value is stored in memory 13 . The transmission count value is reset (that is, set to 0) when all divided frames representing one communication data are transmitted. The transmission processing unit 35 starts transmitting divided frames in accordance with a start instruction, which will be described later, and stops transmitting divided frames in accordance with a stop instruction, which will be described later.

As described above, a plurality of divided frames representing communication data are transmitted by the transmission processing unit 35 to the receiving side (e.g. ECU 20) in the order in which the communication data were generated. The divided frames are received as one piece of communication data on the receiving side only after all the divided frames for one piece of communication data reach the receiving side.

By the way, when transmitting a large amount of data (that is, having a long data length) at a low speed, it takes time to complete the transmission of one piece of communication data. In addition, in this embodiment, a CSMA/CD communication method such as CAN, in which arbitration is performed according to priority, is applied. Therefore, an interrupt of another frame with a higher priority may occur. Therefore, it may take a longer time to complete transmission of one piece of communication data. That is, there is a possibility that the transmission timing for transmitting new communication data (that is, the next transmission timing) will be delayed.

For example, if new communication data is temporarily generated before one piece of communication data is completely transmitted, part of the communication data being transmitted (that is, immediately preceding communication data) becomes the new communication data. may be changed in In this case, after the transmission of all divided frames for the previous communication data is completed, a new divided frame for representing new communication data is transmitted at the next transmission timing. That is, after the transmission of the remaining divided frames of the immediately preceding communication data is completed from the timing when the change occurs, and after the transmission of all the divided frames of the new communication data is completed at the next transmission timing, the new communication data is finally transmitted. Delays can occur as data arrives at the receiver.

Therefore, when the new communication data is generated, the communication confirmation unit 36 sends the transmission processing unit 35 the divided frames for the immediately preceding communication data including the divided data including the changed part in the new communication data. If it has not been sent by , the following process is performed. In other words, the communication confirmation unit 36 converts the data of the changed part from the untransmitted divided frames based on the previous communication data (that is, the communication data before updating) to the new communication data (that is, after updating). (communication data) is replaced with data based on the new divided frames. As a result, from the middle of transmitting the divided frames of the pre-update communication data, the divided data included in the untransmitted divided frames and including the changed portions are the divided data based on the post-update communication data. be replaced by

Note that, when new communication data is generated, if the transmission processing unit 35 has already transmitted the divided frame including the changed portion, the communication confirmation unit 36 determines whether the communication data has not yet been transmitted according to the importance of the communication data. Determines the processing for the transmission split frames.

[2. process]
Next, update processing executed by the communication confirmation unit 36 of the ECU 10 will be described with reference to the flowchart of FIG. This process is repeatedly executed at a predetermined cycle. The period may be shorter than the period in which the application 31 updates the communication data.

First, in step (hereinafter referred to as S) 10, when new communication data is generated by the application 31, the communication confirmation unit 36 compares the previous communication data with the new communication data. , determines whether or not there is a change in the new communication data. A change in the new communication data means that there is a mismatch between the new communication data and the previous communication data.

For example, the communication confirmation unit 36 repeatedly obtains the above-described latest area number in a process different from the update process, and determines that new communication data has been generated by the application 31 when the latest area number changes. good too.

Further, when the communication confirmation unit 36 determines that new communication data has been generated, the communication confirmation unit 36 then compares the new communication data with the previous communication data. Here, when the new communication data and the previous communication data do not match and there is a mismatch, the communication confirmation unit 36 determines that the new communication data has been changed and sets an update flag. On the other hand, if there is no inconsistency, the communication confirmation unit 36 determines that the new communication data has not been changed, and resets the update flag.

Both the new communication data and the previous communication data are stored in the large data storage area. The update flag is a flag that is set when at least part of the communication data is changed due to the update of the communication data by the application 31 . The update flag is stored in memory 13 .

When the new communication data is generated by the application 31, the communication confirmation unit 36 shifts the process to S15 if it determines that the new communication data has been changed, and if it determines that there has been no change. End this update process. Accordingly, when it is determined that the new communication data has not been changed when new communication data is generated, the transmission processing unit 35 continues to reproduce the communication data stored in the divided frame buffer. The divided frames representing the number are repeatedly transmitted in order to the receiving side.

In S15, the communication confirmation unit 36 stops the transmission processing unit 35, which is currently transmitting the divided frames, to stop transmitting the divided frames. Specifically, a stop instruction is output to the stop transmission processing unit 35 . As a result, the transmission processing unit 35 stops sequentially transmitting the divided frames representing the communication data stored in the divided frame buffer (that is, the communication data before updating). Also, the update of the transmission count value is stopped.

Next, in S20, the communication confirmation unit 36 acquires the transmission count value. The transmission count value acquired here indicates the serial number of the divided frame that has already been transmitted among the divided frames representing the communication data before updating.

In subsequent S25, the communication confirmation unit 36 identifies the above-described inconsistent portion between the new communication data and the pre-update communication data as a change portion in the new communication data. Note that in the example shown in FIG. 8, the shaded portion corresponds to the changed portion (that is, the mismatched portion).

Next, in S30, the communication confirmation unit 36 specifies the divided data number (hereinafter referred to as the changed part number) of the divided data containing the changed part. For example, the communication confirmation unit 36 identifies which divided data from the beginning contains the changed portion when the new communication data is divided by the division length, and sets the identified order as the changed portion number. Here, at least one change number is specified. In addition, in the example of FIG. 8, the change part numbers are 2 and 3. FIG.

In S<b>35 , the communication confirmation unit 36 determines whether or not the transmission processing unit 35 has already transmitted the divided frame including the changed part in the new communication data. Specifically, the communication confirmation unit 36 determines that the transmission processing unit 35 has already transmitted the divided frame including the changed portion when the changed portion number is equal to or less than the transmission count value. In other words, when the changed portion number is greater than the transmission count value, the transmission processing unit 35 determines that the divided frame including the changed portion has not been transmitted.

Specifically, for example, in this embodiment, in the example of FIG. 8, when the transmission count value is 3 or more (that is, when the state shown in FIG. 10 to be described later), the communication confirmation unit 36 changes It is determined that the divided frame containing the frame has already been transmitted. On the other hand, when the transmission count value is 1 (that is, when all the divided frames including the changed portion have not been transmitted as shown in FIG. 9 to be described later), it is determined that the divided frame including the changed portion has not been transmitted. do. Also, when the transmission count value is 2 (that is, when at least one of the divided frames including the changed portion has not been transmitted), it is determined that the divided frame including the changed portion has not been transmitted.

In other words, when all the divided frames including the changed part have been transmitted by the transmission processing part 35, the communication confirmation unit 36 determines in S35 that the divided frame including the changed part has been transmitted, and determines that the changed part has been transmitted. If at least one of the divided frames including the modified portion has not been transmitted by the transmission processing unit 35, it is determined in S35 that the divided frame including the changed portion has not been transmitted.

The communication confirmation unit 36 shifts the process to S<b>40 if the transmission processing unit 35 has not transmitted the divided frame including the changed portion, and shifts the process to S<b>50 if the transmission processing unit 35 has already transmitted the divided frame.
The communication confirmation unit 36 generates an update frame in S40, which is performed when it is determined that the divided frame including the changed portion has not been transmitted. An update frame is a divided frame that includes a changed portion and has not yet been transmitted. In the update frame, the communication data before the update is replaced with the new communication data in the changed portion of the data.

Specifically, with reference to FIG. 5, the communication confirmation unit 36 generates a data section for a divided frame using the changed part number as the divided data number and the data of the changed part as the storage data. A divided frame containing the data for the update is generated as an update frame. When generating an update frame, the communication confirmation unit 36 recalculates the CRC of the update frame (that is, the CRC shown in FIG. 3) and uses the recalculated CRC.

Here, for example, in the example of FIG. 8, when the transmission count value is 1, the communication confirmation unit 36 sets the change part number 2 as the divided data number, and sets the divided data No. 2 as the divided data number. 2 is generated as the storage data for the divided frame (hereinafter referred to as the second divided frame data). In addition, the communication confirmation unit 36 assigns 3, which is the changed part number, as the divided data number, and sets the divided data No. 3 as the divided data number. 3 is generated as data for a divided frame (hereinafter referred to as third data for a divided frame). Divided data No. 2 and divided data No. 3 is divided data in the new communication data. Then, the communication confirmation unit 36 generates, as updated frames, both a divided frame containing the second divided frame data as data and a divided frame containing the third divided frame data as data.

Also, the communication confirmation unit 36 generates the last split frame for update in this step. The trailing split frame for update is the trailing split frame among the split frames that have not yet been transmitted after the update frame. The update frame may be the last split frame for update.

As described above, in the divided frame containing the last divided data, the CRC of the last divided data and the entire communication data being transmitted is included as stored data. Therefore, in this step, the communication confirmation unit 36 recalculates the CRC of the entire data including the transmitted divided data and the divided data to be transmitted, and includes the last divided data and the recalculated CRC as stored data. Regenerate the last split frame as follows. Note that when the transmission count value is 1 in the example of FIG. 8, that is, when all the divided frames including the changed portion have not been transmitted, the new CRC of the entire communication data is used as the recalculated CRC.

Then, the communication confirmation unit 36 replaces the untransmitted divided frames that are stored in the divided frame buffer of the memory 13 and that include the changed portions with the update frames. In other words, the update frame is overwritten and saved in the area where the untransmitted divided frames including the changed portion are stored. Furthermore, the communication confirmation unit 36 replaces the untransmitted divided frame stored in the divided frame buffer of the memory 13 and the divided frame including the last divided data with the last divided frame for update. That is, the last split frame for update is overwritten and saved in the split frame buffer.

The communication confirmation unit 36 outputs a start instruction to the transmission processing unit 35 in subsequent S45. The communication confirmation unit 36 ends this update process. As a result, the transmission of the divided frames by the transmission processing unit 35, which has been temporarily suspended by the stop instruction in S15, is resumed, and the update frame is transmitted from the middle of the transmission of the divided frames for representing the communication data before updating. be done. Also, the last divided frame for updating is transmitted.

In S50 to which the communication confirmation unit 36 proceeds when it is determined that the divided frame including the changed part has been transmitted, the communication confirmation unit 36 determines whether or not the communication data that is being transmitted is important. For example, for each type of communication data, whether or not it is important is determined in advance. , may be stored in the memory 13 in advance. The communication confirmation unit 36 may determine whether or not the communication data that is being transmitted is important based on the correspondence information.

The communication confirmation unit 36 shifts the process to S55 when it is determined that the communication data being transmitted is not important, and shifts the process to S60 when it is determined to be important.
The communication confirmation unit 36 outputs a start instruction to the transmission processing unit 35 in S55. The communication confirmation unit 36 ends this update process. As a result, the transmission of the divided frames by the transmission processing unit 35, which has been temporarily suspended by the stop instruction in S15, is resumed, and the remaining divided frames are transmitted by the transmission processing unit 35.

The communication confirmation unit 36 discards the untransmitted divided frames in S60 when it is determined that the divided frames including the changed part have been transmitted and the communication data which is being transmitted is important. do. Specifically, untransmitted divided frames are deleted from the divided frame buffer of the memory 13 . Since divided frames representing communication data are stored in time series in the divided frame buffer, by deleting untransmitted divided frames, transmission of new divided frames of communication data can be started in order. It becomes possible.

The communication confirmation unit 36 outputs a start instruction to the transmission processing unit 35 in S65. The communication confirmation unit 36 ends this update process. As a result, the transmission of the divided frames by the transmission processing unit 35, which has been temporarily suspended by the stop instruction in S15, is resumed, and the transmission processing unit 35 transmits new divided frames of the communication data in order from the beginning of the divided data number. .

[3. effect]
According to the embodiment detailed above, the following effects are obtained.
(1) The communication confirmation unit 36 generates an update frame when the transmission processing unit 35 determines that the divided frame including the changed portion has not been transmitted. The update frame is an untransmitted divided frame including a changed portion, and is obtained by replacing the pre-update communication data in the changed portion with new communication data. Then, the communication confirmation unit 36 replaces the untransmitted divided frames containing the changed portion stored in the divided frame buffer of the memory 13 with the update frames.

That is, as shown in FIG. 9, from the middle of transmitting the divided frame of the communication data before updating, the divided data included in the untransmitted divided frame containing the changed part is changed to the divided data based on the new communication data. be replaced by As a result, the reception side completes reception of new communication data (that is, updated communication data) instead of pre-update communication data when all the divided frames are received. As a result, when transmitting communication data longer than the set data length predetermined in the communication method, when the communication data is newly generated, if the communication data has been updated, it will not be updated. It is possible to suppress the delay until the communication data is transmitted.

(2) In S60, when the transmission processing unit 35 determines that the divided frame including the changed portion has already been transmitted, the communication confirmation unit 36 checks the divided frame in the memory 13 if a predetermined condition is satisfied. The untransmitted split frames stored in the buffer may be discarded. For example, the predetermined condition may be that communication data is important.

In other words, as shown in FIG. 10, when the transmission processing unit 35 determines that the divided frame including the changed part has been transmitted, the communication confirmation unit 36 satisfies the condition that the communication data is important data. If so, untransmitted split frames may be discarded. The divided frame buffer stores divided frames representing communication data in chronological order, and the divided frames are transmitted in the order in which they are stored.
By discarding the untransmitted divided frames representing the communication data before updating, the timing of transmitting the divided frames representing the new communication data (that is, the updated communication data) is advanced. be able to. As a result, it is possible to suppress the delay until the updated communication data is transmitted to the receiving side.

(3) In S55, when the transmission processing unit 35 determines that the divided frame including the change has been transmitted, the communication confirmation unit 36 does not satisfy the condition that the communication data is important data. may continue to transmit untransmitted divided frames. The untransmitted divided frames mentioned here are untransmitted divided frames stored in the divided frame buffer of the memory 13, and are divided frames for representing communication data before updating. As a result, the receiving side can receive the communication data before updating.

(4) Whether or not communication data is important may be determined in advance for each type. In S50, the communication confirmation unit 36 acquires correspondence information in which the type of communication data is associated with information indicating whether it is important or not, and determines whether the communication data is important based on the correspondence information. It may be determined whether Thereby, it is possible to determine the processing for the untransmitted communication frame depending on whether the communication data is important or not.

(5) The transmission processing unit 35 may be configured to start transmitting divided frames according to a start instruction and stop transmitting divided frames according to a stop instruction. For example, in S<b>35 , after outputting the stop instruction to the transmission processing unit 35 , the communication confirmation unit 36 may determine whether or not the division frame including the change has been transmitted by the transmission processing unit 35 . Further, in S<b>40 , the communication confirmation unit 36 may output the start instruction to the transmission processing unit 35 after overwriting the update frame in the divided frame buffer of the memory 13 .

This makes it possible to reliably determine whether or not the divided frame including the changed part has been transmitted. Furthermore, in S55, if the predetermined condition that the communication data is important is not satisfied, the communication confirmation unit 36 outputs a start instruction to the transmission processing unit 35, and may be restarted.

In this embodiment, the ECU 10 and the ECU 20 correspond to the communication device, and the divided frame buffer of the memory 13 corresponds to the divided storage unit. The transmission processing unit 35 corresponds to the transmission execution unit. The communication confirmation unit 36 corresponds to an update determination unit, a transmission determination unit, an unsent update unit, a transmitted processing unit, an important determination unit, a continuation unit, and a transmission restart unit. S10 corresponds to processing as an update determination unit, S35 corresponds to processing as a transmission determination unit, and S40 corresponds to processing as an untransmitted update unit. S60 corresponds to processing as a transmission completion processing unit, S50 corresponds to processing as an importance determination unit, S55 corresponds to processing as a continuation unit, and S65 corresponds to processing as a transmission resuming unit.

[4. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made.

(1) If the memory 13 has a storage area for storing data to be transmitted with the highest priority by the transmission processing unit 35, the communication confirmation unit 36 performs , a plurality of divided frames for representing new communication data may be stored in the storage area. Then, a start instruction may be output to the transmission processing unit 35 in S65. This makes it possible to transmit a plurality of divided frames for representing new communication data more quickly and reliably.

(2) In the above-described embodiment, whether or not each type of communication data is important is determined in advance, and the corresponding information is stored in the memory 13, but the present disclosure is limited to this. not something. For example, communication data may have a predetermined degree of importance, which is indicated by a numerical value, for each type of communication data. The memory 13 may store in advance correspondence data that associates types of communication data with degrees of importance. Also, the degree of importance may be a numerical value indicating that the higher the degree, the more important it is.

Then, in the update process described above, instead of S50 described above, the communication confirmation unit 36 determines that the communication data is important when the importance of the communication data is equal to or greater than a predetermined importance threshold. may

Further, the ECU 10 may be configured to detect the running state of the vehicle, such as the vehicle running or stopped, based on the detection result of a vehicle detection device such as a vehicle speed sensor. Then, the ECU 10 may be configured to change the importance threshold according to the running state of the vehicle, such as when the vehicle is running or stopped.

Here, for example, the importance of communication data necessary while the vehicle is running (hereinafter referred to as importance during driving) is the importance of communication data necessary while the vehicle is stopped, not while the vehicle is running (hereinafter referred to as It may be set to a value greater than the importance level during suspension). On the other hand, the importance threshold value while the vehicle is running is set to be greater than the importance degree while the vehicle is stopped and less than or equal to the importance degree while the vehicle is running, and the importance threshold value while the vehicle is stopped is set to be smaller than the importance degree while the vehicle is stopped. good too. As a result, it is determined that the communication data required while the vehicle is running is important while the vehicle is running.

When the necessary communication data is changed while the vehicle is running, if the divided frames containing the changed parts have already been transmitted, the remaining divided frames containing the changed parts are discarded. be done. As a result, it is possible to quickly transmit new communication data necessary while the vehicle is running.

(3) When the transmission processing unit 35 determines that the transmission processing unit 35 has already transmitted the divided frame including the changed portion, the communication confirmation unit 36 always checks the untransmitted divided frame saved in the divided frame buffer of the memory 13. may be discarded. In this case, S50 and S55 may be deleted in the update process described above. The untransmitted divided frames mentioned here are divided frames for representing untransmitted communication data before updating. As a result, the processing load can be reduced, and the transmission of new communication data (that is, updated communication data) can be accelerated at all times.

(4) The communication data may be one piece of meaningful data, or may be a collection of multiple pieces of meaningful data.
(5) In the above embodiment, the A-ECU 10 and the B-ECU 20 are connected via the CAN standard communication line 5 to form a vehicle network, but the present disclosure is not limited to this. For example, the A-ECU 10 and B-ECU 20 may be connected by Ethernet standard communication lines to form a vehicle network. Note that Ethernet is a registered trademark.

(6) The ECU 10 and techniques thereof described in this disclosure can be performed by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. , may be implemented. Alternatively, the ECU 10 and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the ECU 10 and techniques thereof described in this disclosure may comprise a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. may be implemented by one or more dedicated computers configured as Computer programs may also be stored as computer-executable instructions on a computer-readable non-transitional tangible storage medium. The method of realizing the function of each part included in the ECU 10 does not necessarily include software, and all the functions may be realized using one or more pieces of hardware.

(7) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or a function possessed by one component may be realized by a plurality of components. . Also, a plurality of functions possessed by a plurality of components may be realized by a single component, or a function realized by a plurality of components may be realized by a single component. Also, part of the configuration of the above embodiment may be omitted. Moreover, at least part of the configuration of the above embodiment may be added or replaced with respect to the configuration of the other above embodiment.

(8) In addition to the above-described ECU 10, microcomputer 11, and CPU 12, various forms such as a program for functioning the communication system 1 and the ECU 10, a non-transitional substantive recording medium such as a semiconductor memory in which this program is recorded, and a communication method The present disclosure can also be realized in

5 communication line, 10 ECU, 20 ECU, 13 memory, 35 transmission processing unit, 36 communication confirmation unit.

Claims (8)

At least one communication device (10, 20) among a plurality of communication devices connected to a communication line and communicating according to a predetermined communication method,
Data obtained by dividing communication data whose data length exceeds a set data length set in advance as divided data, each time new communication data is generated in a frame containing each of the divided data a transmission execution unit (35) that sequentially acquires and transmits the divided frames from a divided storage unit that stores the plurality of generated divided frames;
an update determination unit (36, S10) for determining whether or not the new communication data has been changed when the new communication data is generated;
When it is determined that the new communication data has been changed when the new communication data is generated, the transmission executing unit transmits the divided frames including the changed portion in the new communication data. a transmission determination unit (36, S35) that determines whether or not the
When the transmission execution unit determines that the divided frame including the changed portion has not been transmitted, the divided frame including the changed portion that has not been transmitted and the communication data before updating at the changed portion. is replaced with the new communication data to generate an update frame, and the unsent update unit (36 , S40) and
A communication device comprising: A communication device according to claim 1,
the untransmitted frame that is stored in the division storage unit when a predetermined condition is satisfied when the transmission execution unit determines that the division frame including the changed portion has been transmitted; Sent processing unit (36, S60) that discards
A communication device further comprising: A communication device according to claim 2,
The transmitted processing unit always transmits the untransmitted divided frames stored in the division storage unit when the transmission execution unit determines that the divided frames including the changed portion have been transmitted. Communication equipment to be discarded. A communication device according to claim 2,
Importance determination unit (36, S50) for determining whether or not the communication data is important
further comprising
When the transmission execution unit determines that the divided frame including the changed part has been transmitted, the transmission completion processing unit satisfies a condition that the communication data is important data. A communication device that discards the untransmitted divided frames stored in a divided storage unit. A communication device according to claim 4,
The transmitted processing unit
If the condition that the communication data is important data is not satisfied when the transmission executing unit determines that the divided frames including the changed portion have been transmitted, a continuation unit (36, S55) for continuously transmitting the untransmitted divided frames
A communication device further comprising: The communication device according to claim 4 or claim 5,
Whether or not the communication data is important is determined in advance for each type,
The importance determination unit acquires correspondence information in which a type of the communication data is associated with information indicating whether or not the communication data is important, and determines whether the communication data is important based on the correspondence information. A communication device that determines whether or not The communication device according to any one of claims 4 to 6,
The communication data has a predetermined degree of importance, which is indicated by a numerical value, for each type,
The communication device, wherein the importance determination unit determines that the communication data is important when the importance of the communication data is equal to or greater than a predetermined importance threshold. The communication device according to any one of claims 2 to 7,
The transmitted processing unit
After discarding the untransmitted divided frames stored in the divided storage unit, the data obtained by dividing the new communication data into a plurality of divided data is set as the divided data, and a plurality of divided data including each of the divided data is set as the divided data. a transmission resuming unit (36, S65) for causing the transmission executing unit to transmit the divided frames of
A communication device further comprising:

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