JP2016158105A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system which allows for normal communication.SOLUTION: In a communication system, a first micro computer 11 corresponding to CAN but not corresponding to CANFD, and a second micro computer 21 and a third micro computer 31 corresponding to both CAN and CANFD are connected with a communication bus 100. When performing communication by CANFD, the second micro computer 21 instructs transmission and reception prohibition of a message by CAN, for the first micro computer 11. Meanwhile, when instructed to prohibit transmission and reception, the first micro computer 11 prohibits transmission and reception of a message. When prohibiting transmission and reception, the first micro computer 11 determines whether or not the communication by CANFD has ended, and when a determination is made that the communication by CANFD has ended, cancels prohibition of transmission and reception.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication system in which three or more communication devices are connected to a common communication bus.

  Conventionally, there is a communication system disclosed in Patent Document 1 as an example of a communication system in which three or more communication devices are connected to a common communication bus.

  In this communication system, an electronic control device as a communication device is connected to a communication bus. In addition, four electronic control devices are connected to the communication bus. Furthermore, each electronic control unit performs communication according to the CAN protocol. CAN is an abbreviation for Controller Area Network and is a registered trademark.

JP, 2014-53741, A

  By the way, although it is not a prior art, as a communication system, in addition to the CAN protocol, a plurality of communication devices capable of performing communication according to a communication protocol different from the CAN protocol are connected to the communication bus. Is also possible. That is, the communication system includes a second type communication device capable of communication using a common protocol and a non-common protocol, and a first type communication device capable of communication using a common protocol but not a non-common protocol. Can be said to be connected to a common communication bus.

  In the communication system, when the second type communication apparatus is communicating with a non-common protocol, a message with the non-common protocol flows through the communication bus. At this time, the first-type communication device tries to receive a message using a non-common protocol, but cannot receive normally because it is a message using a communication protocol not supported by itself, resulting in a reception error. When the first type communication device becomes a reception error, it is considered that an error message is transmitted to the communication bus using a common protocol in order to notify the other communication devices connected to the communication bus of the reception error. .

  However, in the communication system, an error message in the common protocol flows in the communication bus in which a message in the non-common protocol flows in the communication bus, so that a problem may occur in the message in the non-common protocol. Therefore, in the communication system, when the first type communication device and the second type communication device are connected to a common communication bus, it may happen that communication via the communication bus is not normally performed.

  The present invention has been made in view of the above problems, and an object thereof is to provide a communication system capable of normal communication.

In order to achieve the above object, the present invention provides:
A communication system in which at least one first-type communication device (11) and at least two second-type communication devices (21, 31) are connected to a common communication bus,
The first type communication device and the second type communication device correspond to a common protocol that is a common communication protocol, and can communicate messages via a communication bus using the common protocol.
The type 2 communication device is capable of communicating messages via the communication bus with a non-common protocol that is a communication protocol not supported by the type 1 communication device.
The first type communication device transmits an error message with a common protocol to the communication bus when receiving a message transmitted with a communication protocol not supported by itself.
The second type communication device includes instruction means (S13, S32) for instructing the first type communication device to prohibit transmission of a message using the common protocol when performing communication using a non-common protocol.
The first type communication device
A prohibition means (S22, S41) for prohibiting transmission of a message in a common protocol when transmission prohibition is instructed;
When transmission is prohibited by the prohibition means, it is determined whether or not the communication with the non-common protocol has been completed, and when it is determined that the communication with the non-common protocol has been completed, the release means for canceling the prohibition of transmission (S23, S24, S42, S43).

  Thus, in the present invention, the second type communication device corresponding to the common protocol and the non-common protocol and the first type communication device corresponding to the common protocol but not the non-common protocol are common. Connected to the communication bus. Further, when the first type communication device receives a message transmitted by a communication protocol that is not supported by itself, the first type communication device transmits an error message to the communication bus.

  When performing communication using the non-common protocol, the second type communication device instructs the first type communication device to prohibit message transmission using the common protocol. On the other hand, when the first type communication apparatus is instructed to prohibit transmission, the first type communication apparatus prohibits message transmission using the common protocol. For this reason, even if the type 1 communication device receives a message of a communication protocol not supported by itself when the type 2 communication device performs communication using a non-common protocol, Do not send error messages. Therefore, this invention can suppress that a malfunction arises in the message by the non-common protocol which is flowing into the communication bus. Therefore, the present invention can perform communication normally.

  In addition, when the transmission of the message using the common protocol is prohibited, the first type communication apparatus determines whether the communication using the non-common protocol is finished. When the first type communication apparatus determines that the communication using the non-common protocol has ended, it cancels the prohibition of transmission. Therefore, according to the present invention, even if communication using the common protocol is prohibited, communication using the common protocol can be performed when communication using the non-common protocol is completed.

  The reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later as one aspect, and the technical scope of the invention is as follows. It is not limited.

It is a block diagram which shows schematic structure of the communication system in embodiment. It is an image figure which shows the transmission / reception state of each microcomputer in embodiment. It is a flowchart which shows the processing operation of the 2nd microcomputer in embodiment. It is a flowchart which shows the processing operation of the 1st microcomputer in embodiment. It is an image figure which shows the transmission / reception state of each microcomputer in the modification 1. 10 is a flowchart showing a processing operation of a second microcomputer in Modification 1; 10 is a flowchart showing a processing operation of a first microcomputer in Modification 1; FIG. 10 is a block diagram illustrating a schematic configuration of a communication system in a second modification.

  Hereinafter, a plurality of embodiments for carrying out the invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

  First, the configuration of the communication system will be described with reference to FIG. In the communication system, the first ECU 10 to the third ECU 30 are connected to a common communication bus 100. In the communication system, the first microcomputer 11 provided in the first ECU 10, the second microcomputer 21 provided in the second ECU 20, and the third microcomputer 31 provided in the third ECU 30 are connected to a common communication bus 100. I can also say. The communication system can be applied to, for example, an in-vehicle network mounted on a vehicle. Therefore, each of the first ECU 10 to the third ECU 30 can be applied to an electronic control device that performs various controls in the vehicle. ECU is an abbreviation for Electronic Control Unit.

  Each of the first microcomputer 11 to the third microcomputer 31 performs data transfer via the communication bus 100. In other words, each of the first microcomputer 11 to the third microcomputer 31 transmits and receives a message including data via the communication bus 100 in accordance with a predetermined communication protocol.

  Various communication protocols exist, and examples thereof include CAN, CANFD, TTCAN, and the like. The CANFD and TTCAN conform to ISO11898, but the format of CAN and some transmission frames is different. In addition, there are also FlexRay (registered trademark) and LIN as communication protocols. CANFD is an abbreviation for CAN with Flexible Data Rate. TTCAN is an abbreviation for Time Trigger CAN. LIN is an abbreviation for Local Interconnect Network.

  The communication system performs communication using a plurality of communication protocols. In the present embodiment, as an example, a communication system in which communication by CAN and communication by CANFD are performed is employed. The first microcomputer 11 corresponds to CAN, but does not correspond to CANFD. On the other hand, the second microcomputer 21 and the third microcomputer 31 correspond to both CAN and CANFD.

  Therefore, the first microcomputer 11 to the third microcomputer 31 can communicate messages via the communication bus 100 by CAN. In other words, the first microcomputer 11 to the third microcomputer 31 can transmit and receive messages via the communication bus 100 in accordance with CAN. The second microcomputer 21 and the third microcomputer 31 can communicate messages via the communication bus 100 using CAN and CANFD. In other words, the second microcomputer 21 and the third microcomputer 31 can send and receive messages via the communication bus 100 according to CAN, and can send and receive messages via the communication bus 100 according to CANFD. It is.

  Thus, the 1st microcomputer 11 is equivalent to the 1st type communication device in a claim. The second microcomputer 21 and the third microcomputer 31 correspond to the second type communication device in the claims. CAN corresponds to a common protocol in the claims. CANFD corresponds to a non-common protocol in the claims.

  In the following, a message transmitted by CAN is also referred to as a CAN message, and a message transmitted by CANFD is also referred to as a CANFD message. In the following, CAN communication is also referred to as CAN communication, and CANFD communication is also referred to as CANFD communication.

  The communication bus 100 is a two-wire communication line including a high potential side line and a low potential side line. Note that the high potential and the low potential in the high potential side line and the low potential side line indicate relative potentials between the lines. Communication via the communication bus 100 is established by a differential voltage (potential difference) generated between the high potential side line and the low potential side line.

  The first ECU 10 includes a first microcomputer 11, a first transceiver 12, and the like. The first microcomputer 11 is a so-called microcontroller having a CPU, a ROM, a RAM, a register, and the like. CPU is an abbreviation for Central Processing Unit. ROM is an abbreviation for Read Only Memory. RAM is an abbreviation for Random Access Memory.

  The first microcomputer 11 receives a message flowing through the communication bus 100 via the first transceiver 12 and transmits a CAN message to the communication bus 100. Therefore, it can be said that the first microcomputer 11 includes a communication controller for performing communication via the communication bus 100. For example, the first microcomputer 11 performs various controls based on data included in the received CAN message.

  Further, when the first microcomputer 11 receives a message transmitted by a communication protocol that is not supported by the first microcomputer 11, the first microcomputer 11 cannot receive normally and a reception error occurs. Then, in the case of a reception error, the first microcomputer 11 transmits an error message to the communication bus 100 by CAN.

  The first transceiver 12 establishes communication on the communication bus 100 by generating a potential difference between the high potential side line and the low potential side line in accordance with the output level (logic level) of the first microcomputer 11. That is, the first transceiver 12 sets the communication bus 100 to either a dominant or recessive potential according to the output level from the first microcomputer 11. The first transceiver 12 converts the potential difference between the high potential side line and the low potential side line into a logic level in the first microcomputer 11 and outputs the logical level to the first microcomputer 11. Thus, the first transceiver 12 can be said to be a communication interface.

  The second ECU 20 includes a second microcomputer 21, a second transceiver 22, and the like. The configuration of the second microcomputer 21 is the same as that of the first microcomputer 11. The configuration of the second transceiver 22 is the same as the configuration of the first transceiver 12. Therefore, the description regarding the same points as the first microcomputer 11 in the second microcomputer 21 and the same points as the second transceiver 22 and the first transceiver 12 is omitted here.

  Unlike the first microcomputer 11, the second microcomputer 21 also supports CANFD. That is, the second microcomputer 21 corresponds to CAN and CANFD. For this reason, the second microcomputer 21 receives the CAN message and the CANFD message flowing through the communication bus 100 and transmits the CAN message and the CANFD message to the communication bus 100. For example, the second microcomputer 21 executes various controls based on data included in the received CAN message or CANFD message. When the second microcomputer 21 receives a message transmitted with a communication protocol that is not supported by the second microcomputer 21, the second microcomputer 21 may transmit an error message according to the protocol to the communication bus 100.

  Further, as will be described in detail later, the second microcomputer 21 uses a CAN message to provide advance notice information that informs that the CANFD message flows and time information that informs the timing when the first microcomputer 11 transitions from the transmission / reception stop state to the transmission / reception enabled state. Send.

  The third ECU 30 includes a third microcomputer 31, a third transceiver 32, and the like. Since the third ECU 30 is the same as the second ECU 20, the description thereof is omitted.

  Here, the processing operation of the first microcomputer 11 to the third microcomputer 31 will be described with reference to FIGS.

  First, the processing operation of the second microcomputer 21 will be described with reference to FIG. The second microcomputer 21 executes the processing shown in the flowchart of FIG. 3 at every predetermined time, that is, every predetermined timing. The third microcomputer 31 performs the same process as the second microcomputer 21. For this reason, the description of the processing operation of the third microcomputer 31 is omitted.

  In step S10, it is determined whether or not to transmit by CANFD. Each time the second microcomputer 21 prepares to send a message, the second microcomputer 21 determines whether to send a CAN message or a CANFD message. The second microcomputer 21 proceeds to step S11 if it is determined to transmit by CANFD, and proceeds to step S16 if it is determined not to transmit by CANFD and is transmitted by CAN.

  In step S16, the message is transmitted by CAN. That is, the second microcomputer 21 transmits a CAN message. At this time, the second microcomputer 21 outputs a CAN message to the communication bus 100 via the second transceiver 22.

  For example, the first message in FIG. 2 is a CAN message. Therefore, if the second microcomputer 21 determines that transmission is not performed using CANFD in preparation for transmission for sending a message at timing t1, transmission is performed using CAN. Then, the second microcomputer 21 transmits the first message at timing t1. At this time, the first microcomputer 11 and the third microcomputer 31 are normally received because they correspond to CAN.

  In step S11, the advance notice information is converted into data. In step S12, time information is converted into data. The second microcomputer 21 sets the notice information and the time information in a state that can be transmitted by a CAN message.

  During the CANFD communication, the second microcomputer 21 prohibits the first microcomputer 11 from performing transmission / reception via the CAN during the CANFD communication so that the CAN message does not flow through the communication bus 100. In addition, when the CAN FD communication is completed, the second microcomputer 21 permits the first microcomputer 11 to perform transmission / reception with the prohibited CAN. The advance notice information and the time information are information for prohibiting transmission / reception of a CAN message as described above and permitting transmission / reception in the prohibited CAN.

  As will be described later, when the first microcomputer 11 acquires the advance notice information, the first microcomputer 11 prohibits message transmission / reception via the CAN. That is, the first microcomputer 11 is in a transmission / reception stop state by itself. Accordingly, the advance notice information can be said to be information that instructs the first microcomputer 11 to prohibit transmission / reception by CAN. Therefore, the first microcomputer 11 has a communication invalid period while it is in a transmission / reception stop state.

  The time information corresponds to the duration of CAN FD communication and corresponds to a communication invalid period. The time information can also be said to be a prohibition time from instructing the prohibition of transmission / reception until a message can be transmitted / received by CAN. As described above, the second microcomputer 21 can notify the first microcomputer 11 of the timing at which the first microcomputer 11 shifts from the transmission / reception stop state to the transmission / reception enabled state by transmitting time information.

  The second microcomputer 21 calculates the duration of CANFD communication based on the number of data scheduled to be transmitted in CANFD communication and the communication speed in communication via the communication bus 100. That is, the CANFD message is different for each transmission timing in CANFD communication. For this reason, the 2nd microcomputer 21 calculates the duration of CANFD communication for every transmission timing in CANFD communication. Then, the second microcomputer 21 generates time information as information indicating the duration. Thereby, the second microcomputer 21 can instruct the minimum necessary time as the communication invalid period.

  In step S13, a message including notice information and time information is transmitted by CAN (instruction means). At this time, the second microcomputer 21 outputs a CAN message including notice information and time information to the communication bus 100 via the second transceiver 22. That is, when performing the CAN FD communication, the second microcomputer 21 instructs the first microcomputer 11 to prohibit the transmission of a message by CAN. Further, in addition to the instruction to prohibit transmission, the second microcomputer 21 instructs the first microcomputer 11 about a prohibition time from when the transmission prohibition is instructed until the CAN can transmit and receive messages. As described above, when the second microcomputer 21 transmits the CANFD message, the second microcomputer 21 sets the prohibition time until the CAN message transmission / reception is prohibited and the CAN message transmission / reception is enabled before the CANFD message is transmitted. One microcomputer 11 is instructed. The message transmission / reception via CAN means that CANFD communication is not being performed and there is no problem even if a CAN message is sent to the communication bus 100. The communication system can easily determine whether or not the data included in the message received by the first microcomputer 11 is the advance notice information by fixing the advance notice information to a specific value.

  In the present embodiment, an example in which transmission / reception prohibition is instructed in step S13 is employed. However, the present invention is not limited to this. In step S13, the reception prohibition may not be instructed and the transmission prohibition may be instructed. In this case, the prohibition time is the time from when the transmission prohibition is instructed to when the CAN message can be transmitted.

  In step S14, it is determined whether or not transmission by CAN is completed. The second microcomputer 21 proceeds to step S15 when it is determined that the CAN transmission is completed, and returns to step S13 when it is determined that the CAN transmission is not completed. That is, the second microcomputer 21 determines whether or not transmission of a CAN message including notice information and time information is completed.

  In step S15, the message is transmitted by CANFD. That is, the second microcomputer 21 transmits the CANFD message determined to be transmitted in step S10 this time. At this time, the second microcomputer 21 outputs a CANFD message to the communication bus 100 via the second transceiver 22.

  For example, in FIG. 2, the second message is a CAN message including notice information and time information, and the third message is a CANFD message. The second microcomputer 21 transmits the second message at the timing t2 before transmitting the CANFD message at the timing t3 when it is determined to transmit the CANFD message at the timing t3 in the transmission preparation for transmitting the message at the timing t3. That is, the second microcomputer 21 transmits the CANFD message at timing t3 after transmitting the second message at timing t2. As described above, when transmitting the CANFD message, the second microcomputer 21 informs the first microcomputer 11 that the CANFD message is transmitted before transmitting the CANFD message. In addition, since the 1st microcomputer 11 and the 3rd microcomputer 31 respond | correspond to CAN, they can receive a 2nd message normally.

  Next, the processing operation of the first microcomputer 11 will be described with reference to FIG. When the first microcomputer 11 receives the CAN message, the first microcomputer 11 executes the process shown in the flowchart of FIG.

  In step S20, it is determined whether or not there is advance notice information. If the CAN message received this time includes the advance notice information, the first microcomputer 11 determines that there is advance notice information and proceeds to step S21. Further, when the CAN message received this time does not include the advance notice information, the first microcomputer 11 determines that there is no advance notice information and proceeds to step S25. It is assumed that the CAN message including the advance notice information also includes time information. Therefore, when the first microcomputer 11 determines in step S11 that the notice information is present, the first microcomputer 11 has received the notice information and the time information.

  In step S25, normal reception is performed. That is, the first microcomputer 11 receives the CAN message without executing steps S21 to S24 described later. Then, the first microcomputer 11 executes processing based on data included in the CAN message.

  In step S21, a timer operation is started. The first microcomputer 11 starts a timer operation in order to confirm the timing at which the elapsed time after receiving the advance notice information reaches the time indicated by the time information. That is, the first microcomputer 11 starts a timer operation in order to confirm the timing for shifting from the transmission / reception stop state instructed by the second microcomputer 21 to the transmission / reception enabled state. The elapsed time after receiving the advance notice information can be regarded as equivalent to the elapsed time after transmission / reception is stopped. Therefore, it can be said that the first microcomputer 11 measures the elapsed time after stopping transmission and reception in step S21.

  In step S22, communication is stopped (prohibiting means). When receiving the advance notice information, the first microcomputer 11 stops the CAN communication. That is, when the first microcomputer 11 is instructed to prohibit transmission / reception from the second microcomputer 21, the first microcomputer 11 prohibits message transmission / reception via the CAN. In addition, the first microcomputer 11 can be rephrased as shifting the CAN mode to the communication stop mode. Therefore, as shown in FIG. 2, when the first microcomputer 11 receives the second message, it enters a communication invalid period.

  When the second microcomputer 21 does not instruct prohibition of reception and instructs prohibition of transmission, the first microcomputer 11 does not prohibit reception by CAN and prohibits transmission by CAN in step S22. The first microcomputer 11 may execute the process of step S21 after executing the process of step S22.

  In step S23, it is determined whether time information has been reached (release means). The first microcomputer 11 determines whether or not the elapsed time after receiving the advance notice information has reached the time indicated by the time information. If it is not determined that the time information has been reached, the first microcomputer 11 regards the CANFD communication as continuing and repeats the comparison in step S23. If the first microcomputer 11 determines that the time information has been reached, the first microcomputer 11 considers that the CANFD communication has ended, and proceeds to step S24. As described above, the first microcomputer 11 determines whether or not the CANFD communication has ended by determining whether or not the elapsed time since the reception of the advance notice information has reached the time indicated by the time information. .

  In step S24, communication is resumed (release means). The first microcomputer 11 resumes the transmission / reception prohibited in step S22. As described above, when the first microcomputer 11 determines that the CAN FD communication is completed when the transmission / reception is prohibited, the first microcomputer 11 cancels the prohibition of transmission / reception. That is, the first microcomputer 11 can resume transmission / reception in CAN when CANFD communication ends. For example, the first microcomputer 11 resumes communication at the timing t4 in FIG.

  In this way, the first microcomputer 11 forms a communication invalid period as shown in FIG. The second microcomputer 21 transmits a third message that is a CANFD message at timing t3. At this time, the third microcomputer 31 can normally receive the third message because it corresponds to CANFD. As shown in FIG. 2, the timing t <b> 3 is included in the communication invalid period of the first microcomputer 11. Therefore, the first microcomputer 11 does not receive the third message.

  Therefore, the first microcomputer 11 does not cause a reception error even if a CANFD message that does not correspond to the first microcomputer 11 flows on the communication bus 100. That is, the first microcomputer 11 does not transmit an error message by CAN even if a CANFD message that does not correspond to the first microcomputer 11 flows in the communication bus 100. For this reason, the communication system can suppress the occurrence of problems in the CANFD message flowing in the communication bus 100. In other words, the communication system can suppress the CAN message from flowing to the communication bus 100 from being destroyed. That is, in the communication system, CANFD communication is normally performed.

  Therefore, in the communication system, although both the CAN message and the CANFD message flow through the communication bus 100, transmission / reception succeeds normally on the communication bus 100. In other words, the communication system can coexist with the second microcomputer 21 and the like corresponding to CAN and CANFD and the first microcomputer 11 corresponding to CAN but not corresponding to CANFD.

  Moreover, the 1st microcomputer 11 determines whether the CANFD communication was complete | finished, when transmission / reception of a CAN message is prohibited. If the first microcomputer 11 determines that the CAN FD communication has ended, the first microcomputer 11 cancels the prohibition of transmission / reception. Therefore, even if CAN communication is prohibited, the communication system can perform CAN communication when CANFD communication ends.

  Furthermore, since the communication system can perform normal communication as described above, the first microcomputer 11 does not need to be a microcomputer corresponding to CAN and CANFD. Therefore, the communication system can perform normal communication while suppressing an increase in cost.

  Note that the communication system can achieve the same effect even when the second microcomputer 21 does not instruct reception prohibition but instructs transmission prohibition. In this case, when the first microcomputer 11 is instructed to prohibit transmission from the second microcomputer 21, the first microcomputer 11 prohibits transmission of a message through the CAN. For this reason, the first microcomputer 11 does not transmit an error message to the communication bus 100 even if the second microcomputer 21 or the like is performing CANFD communication, even if it receives a CANFD message. Therefore, the communication system can suppress the occurrence of problems in the CANFD message flowing in the communication bus 100.

  The second microcomputer 21 instructs the first microcomputer 11 with a CAN message when instructing transmission prohibition and prohibition time. For this reason, the communication system can instruct the first microcomputer 11 from the second microcomputer 21 without changing the hardware configuration of the first microcomputer 11 and the second microcomputer 21. That is, the communication system does not need to add a hardware configuration for giving instructions to the first microcomputer 11 and the second microcomputer 21.

  In the present embodiment, one of the first microcomputers 11 is employed as the first type communication device in the claims. However, the present invention is not limited to this, and may include a plurality of first type communication devices. That is, the present invention may include a plurality of microcomputers similar to the first microcomputer 11.

  In the present embodiment, the second microcomputer 21 and the third microcomputer 31 are employed as the second type communication device in the claims. However, the present invention is not limited to this, and may include three or more second-type communication devices. That is, the present invention may include three or more microcomputers similar to the second microcomputer 21 and the third microcomputer 31.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. Below, the modification of this invention is demonstrated.

  Below, the modifications 1-3 of this invention are demonstrated. The above-described embodiment and Modifications 1 to 3 can be implemented independently, but can be implemented in appropriate combination. The present invention is not limited to the combinations shown in the embodiments, and can be implemented by various combinations.

(Modification 1)
Here, the communication system according to the first modification will be described with reference to FIGS. The configuration of the communication system of the first modification is the same as that of the above embodiment. For this reason, it demonstrates using the code | symbol similar to the said embodiment here. The communication system of the modification 1 mainly differs from the above embodiment in the processing of the second microcomputer 21.

  First, the processing operation of the second microcomputer 21 will be described with reference to FIG. The second microcomputer 21 executes the process shown in the flowchart of FIG. 6 at every predetermined time, that is, at a predetermined timing. The third microcomputer 31 performs the same process as the second microcomputer 21. For this reason, the description of the processing operation of the third microcomputer 31 is omitted.

  In step S30, as in step S10, it is determined whether or not to transmit by CANFD. The second microcomputer 21 proceeds to step S31 if it is determined to transmit by CANFD, and proceeds to step S37 if it is determined not to transmit by CANFD.

  Step S37 is the same as step S16. For example, the fourth message in FIG. 5 is a CAN message. Therefore, if the second microcomputer 21 determines that transmission is not performed by CANFD in transmission preparation for sending a message at timing t5, it is regarded as transmission by CAN. Then, the second microcomputer 21 transmits the fourth message at timing t5. At this time, the first microcomputer 11 and the third microcomputer 31 are normally received because they correspond to CAN.

  In step S31, the notice information is converted into data as in step S11. The second microcomputer 21 sets the notice information in a state where it can be transmitted by a CAN message. The notice information here is information for instructing the first microcomputer 11 to prohibit transmission by CAN without prohibiting reception by CAN.

  In step S32, a message including notice information is transmitted by CAN (instruction means). At this time, the second microcomputer 21 outputs a CAN message including notice information to the communication bus 100 via the second transceiver 22. When performing the CAN FD communication, the second microcomputer 21 instructs the first microcomputer 11 to prohibit the message transmission by the CAN. As described above, the second microcomputer 21 of Modification 1 does not transmit the time information to the first microcomputer 11.

  In step S33, a message is transmitted by CANFD as in step S15. Thereafter, in step S34, it is determined whether or not transmission by CANFD has been completed. The second microcomputer 21 proceeds to step S35 when it is determined that the CANFD transmission is completed, and returns to step S33 when it is determined that the CANFD transmission is not completed.

  For example, in FIG. 5, the fifth message is a CAN message including notice information, and the sixth message is a CANFD message. The second microcomputer 21 transmits the fifth message at the timing t6 before transmitting the CANFD message at the timing t7 when it is determined to transmit the CANFD at the timing t7 in the transmission preparation for transmitting the message at the timing t7. That is, the second microcomputer 21 transmits the CANFD message at timing t7 after transmitting the fifth message at timing t6. As described above, when transmitting the CANFD message, the second microcomputer 21 informs the first microcomputer 11 that the CANFD message is transmitted before transmitting the CANFD message. In addition, since the 1st microcomputer 11 and the 3rd microcomputer 31 respond | correspond to CAN, they can receive a 5th message normally.

  In step S35, the end information is converted into data. The end information is information indicating that transmission by CANFD has ended. The end information can also be said to be information indicating the timing at which the first microcomputer 11 shifts from the transmission stop state to the transmittable state. The second microcomputer 21 is in a state where the end information can be transmitted by a CAN message.

  In step S36, a message including the end information is transmitted by CAN (end notification means). When the CANFD communication is completed, the second microcomputer 21 notifies the first microcomputer 11 that the CANFD communication is completed by transmitting a message including the termination information by CAN. The second microcomputer 21 can notify the timing at which the first microcomputer 11 shifts from the transmission stop state to the transmittable state by transmitting the end information to the first microcomputer 11.

  For example, the seventh message in FIG. 5 is a CAN message including termination information. When the transmission of the CANFD message ends at timing t7, the second microcomputer 21 transmits a CAN message including termination information at timing t8. At this time, the first microcomputer 11 and the third microcomputer 31 are normally received because they correspond to CAN.

  As described above, the second microcomputer 21 notifies the end of CANFD communication by the CAN message. For this reason, the communication system of the modification 1 does not need to add a hardware configuration for performing notification to the first microcomputer 11 and the second microcomputer 21.

  Next, the processing operation of the first microcomputer 11 will be described with reference to FIG. When the first microcomputer 11 receives the CAN message, the first microcomputer 11 executes the process shown in the flowchart of FIG.

  In step S40, as in step S20, it is determined whether or not there is notice information. If the CAN message received this time includes the advance notice information, the first microcomputer 11 determines that there is advance notice information and proceeds to step S41. Further, when the CAN message received this time does not include the advance notice information, the first microcomputer 11 determines that there is no advance notice information and proceeds to step S42.

  In step S41, a transition is made to a mode in which only reception is possible (prohibiting means). When the first microcomputer 11 receives the advance notice information, the first microcomputer 11 prohibits transmission by CAN. That is, when the first microcomputer 11 is instructed to prohibit transmission from the second microcomputer 21, the first microcomputer 11 prohibits transmission of a message through the CAN. Therefore, as shown in FIG. 5, when the first microcomputer 11 receives the fifth message, it enters a communication invalid period. Note that, unlike the first microcomputer 11 of the above-described embodiment, the first microcomputer 11 of Modification 1 can receive a CAN message. Therefore, the communication invalid period of the first modification indicates a transmission invalid period.

  The second microcomputer 21 transmits a CANFD message at timing t7 included in this communication invalid period. At this time, the third microcomputer 31 is normally received because it corresponds to CANFD. On the other hand, since the first microcomputer 11 does not support CANFD, a reception error occurs. However, since the first microcomputer 11 prohibits transmission, the first microcomputer 11 does not transmit an error message. That is, the communication system according to the first modification can suppress a CAN message from flowing through the communication bus 100 even if the first microcomputer 11 has a reception error.

  In step S42, it is determined whether there is end information (release means). When the first microcomputer 11 prohibits transmission, the first microcomputer 11 determines whether CANFD communication has ended. If the CAN message received this time includes end information, the first microcomputer 11 determines that there is end information and proceeds to step S43. Further, if the CAN message received this time does not include end information, the first microcomputer 11 determines that there is no end information, and proceeds to step S44. In step S44, normal reception is performed as in step S25. Note that the first microcomputer 11 may determine that the CAN FD communication has ended when a CAN message is received in a state where transmission is prohibited.

  As described above, the second microcomputer 21 transmits the seventh message including the end information at the timing t8. This seventh message is a CAN message. For this reason, the first microcomputer 11 can receive the end information included in the seventh message although it is in the transmission invalid period.

  In step S43, a transition is made to a mode in which transmission / reception is possible (release means). When receiving the end information, the first microcomputer 11 determines that the CAN FD communication has ended, and cancels the prohibition of transmission. For example, the first microcomputer 11 resumes communication at the timing t9 in FIG.

  The communication system of the modification 1 can have the same effect as the above embodiment. Furthermore, since the communication system of the first modification notifies the first microcomputer 11 that the CANFD communication has actually ended, it is possible to notify the end timing of the CANFD communication more accurately than in the above embodiment. Therefore, in the communication system according to the first modification example, the first microcomputer 11 can easily shift from the transmission stop state to the transmittable state at the timing when the CAN FD communication ends. For this reason, in the communication system of the modification 1, the transmission invalid period of the 1st microcomputer 11 can be optimized. In other words, in the communication system of the first modification, the transmission prohibition of the first microcomputer 11 is canceled in the situation where the CANFD communication is being performed, or the transmission prohibition of the first microcomputer 11 is prohibited even though the CANFD communication is terminated. Can be prevented from being released. In particular, the second microcomputer 21 may not be able to accurately calculate the duration of CANFD communication when the CANFD message is continuously transmitted a plurality of times. Therefore, the communication system according to the first modification is effective when the CANFD message is continuously transmitted a plurality of times.

(Modification 2)
Here, the communication system according to the second modification will be described with reference to FIG. Here, regarding the same configuration as that of the above-described embodiment, the same reference numerals as those of the above-described embodiment are used and description thereof is omitted. The communication system of the modification 2 is different from the above embodiment mainly in that the second microcomputer 21 and the third microcomputer 31 give instructions to the first microcomputer 11 using the dedicated lines 210 and 220.

  As shown in FIG. 8, the communication system according to the second modification includes a first ECU 10a, a second ECU 20a, and a third ECU 30a. The first ECU 10a is connected to the second ECU 20a via a dedicated line 210, and is connected to the third ECU 30a via a dedicated line 220. The dedicated lines 210 and 220 are lines such as metal wires that electrically connect the first ECU 10a and the second ECU 20a, and the first ECU 10a and the third ECU 30a, and can also be referred to as direct lines. The dedicated lines 210 and 220 are different from the communication bus 100 and correspond to signal lines in the claims.

  Unlike the first ECU 10, the first ECU 10a includes a first port 13 to which dedicated lines 210 and 220 are electrically connected. Unlike the second ECU 20, the second ECU 20a includes a second port 23 to which a dedicated line 210 is electrically connected. Unlike the third ECU 30, the third ECU 30 a includes a third port 33 to which the dedicated line 220 is electrically connected. As described above, the dedicated line 210 directly connects the first port 13 and the second port 23. Similarly, the dedicated line 220 directly connects the first port 13 and the third port 33.

  The first ECU 10a and the second ECU 20a can transmit signals by setting the levels of the first port 13 and the second port 23 to high or low. Similarly, the first ECU 10a and the third ECU 30a can transmit signals by setting the levels of the first port 13 and the third port 33 to high or low.

  The second port 23 is at a low level when the second microcomputer 21 does not perform CANFD communication. Then, when starting the CANFD communication, the second microcomputer 21 sets the second port 23 to the high level before starting the CANFD communication. Then, when the CANFD communication ends, the second microcomputer 21 sets the second port 23 to the low level.

  On the other hand, the first microcomputer 11 prohibits CAN transmission / reception when the first port 13 changes from low level to high level, and cancels the CAN transmission / reception prohibition when the first port 13 changes from high level to low level. . Note that the first microcomputer 11 may prohibit only CAN transmission, as in the above-described embodiment and the first modification.

  As described above, the second microcomputer 21 uses the dedicated line 210 to instruct the first microcomputer 11 to prohibit transmission / reception in CAN and to cancel the prohibition of transmission / reception. It can also be said that the second microcomputer 21 uses the dedicated line 210 to notify the first microcomputer 11 that the CANFD communication has ended. Note that the third microcomputer 31 performs the same processing as the second microcomputer 21 using the dedicated line 220.

  The communication system of the modification 2 can have the same effect as the above embodiment. Furthermore, since the communication system of the modification 2 can instruct | indicate to the 1st microcomputer 11 from the 2nd microcomputer 21 without using the communication bus 100, it can suppress that the occupation rate of the communication bus 100 increases. Note that the dedicated lines 210 and 220 may be individually connected to the first ECU 10a. That is, the first ECU 10a may be provided with a port to which the dedicated line 210 is connected and a port to which the dedicated line 220 is connected.

(Modification 3)
Here, a communication system according to Modification 3 will be described. The configuration of the communication system of Modification 3 is the same as that of the above embodiment. For this reason, it demonstrates using the code | symbol similar to the said embodiment here. The communication system of Modification 3 mainly differs from the above embodiment in the processing of the first microcomputer 11 and the second microcomputer 21.

  When the first microcomputer 11 receives the advance notice information and prohibits transmission / reception via CAN, the first microcomputer 11 measures an elapsed time since the transmission / reception is prohibited. Then, when the elapsed time reaches a predetermined value set in advance, the first microcomputer 11 determines that the CAN FD communication has ended and cancels the prohibition of transmission / reception (release means). The communication system of the modification 3 is applicable when the communication time in CANFD communication is determined in advance. And the said predetermined value can employ | adopt the longest communication time etc. among the CANFD communications performed with a communication system, for example. Note that the first microcomputer 11 may prohibit only CAN transmission, as in the above-described embodiment and the first modification.

  The communication system of the modification 3 can have the same effect as the above embodiment. Furthermore, in the communication system of the third modification, the second microcomputer 21 and the third microcomputer 31 do not need to transmit time information and end information to the first microcomputer 11. The first microcomputer 11 can cancel the prohibition of transmission and reception without receiving time information and end information. Therefore, the communication system of the modification 3 can reduce the occupation rate of the communication bus 100 as compared with the above embodiment.

  10, 10a 1st ECU, 11 1st microcomputer, 12 1st transceiver, 13 1st port, 20, 20a 2ECU, 21 2nd microcomputer, 22 2nd transceiver, 23 2nd port, 30, 30a 3ECU, 31 1st 3 microcomputer, 32 3rd transceiver, 33 3rd port, 100 communication bus, 210, 220 leased line

Claims (9)

A communication system in which at least one first-type communication device (11) and at least two second-type communication devices (21, 31) are connected to a common communication bus,
The first type communication device and the second type communication device correspond to a common protocol that is a common communication protocol, and message communication via the communication bus is possible using the common protocol,
The second type communication device is capable of communicating messages via the communication bus with a non-common protocol that is a communication protocol not supported by the first type communication device.
When the first type communication device receives a message transmitted with a communication protocol that is not supported by itself, the first type communication device transmits an error message with the common protocol to the communication bus,
The second type communication device includes instruction means (S13, S32) for instructing the first type communication device to prohibit transmission of a message using the common protocol when performing communication using the non-common protocol. And
The first type communication device is:
When the transmission prohibition is instructed, prohibition means (S22, S41) for prohibiting the transmission of the message in the common protocol;
When transmission is prohibited by the prohibition means, it is determined whether or not communication with the non-common protocol has been completed. When it is determined that communication with the non-common protocol has been completed, the prohibition of transmission is canceled. Release means (S23, S24, S42, S43) to perform,
A communication system comprising: In addition to the instruction to prohibit transmission, the instructing means (S13) sets a prohibition time from instructing the transmission prohibition until the message can be transmitted using the common protocol to the first type communication device. And instruct
The release means (S23, S24) measures an elapsed time since transmission is prohibited by the prohibit means, and when the elapsed time reaches the prohibited time, communication using the non-common protocol is completed. The communication system according to claim 1, wherein the prohibition of transmission is canceled based on the determination. The instructing means (S13) is for instructing message reception prohibition in addition to the message prohibition instruction in the common protocol.
The communication system according to claim 2, wherein the prohibiting means (S22) prohibits reception of a message when reception prohibition is instructed. When the communication using the non-common protocol is completed, the second type communication device includes an end notification unit (S36) for notifying the first type communication device that communication using the non-common protocol is completed. Has
The canceling means (S42, S43), when notified from the end notification means, determines that communication using the non-common protocol has ended and cancels the prohibition of transmission. The communication system described.   The communication system according to any one of claims 1 to 4, wherein the instruction unit performs an instruction using a message in the common protocol.   The communication system according to claim 4, wherein the end notification unit performs notification using a message in the common protocol. A signal line different from the communication bus that electrically connects the first type communication device and the second type communication device;
The communication system according to any one of claims 1 to 4, wherein the instruction unit performs an instruction through the signal line. A signal line different from the communication bus that electrically connects the first type communication device and the second type communication device;
The communication system according to claim 4, wherein the end notification unit performs notification through the signal line.   The canceling unit measures an elapsed time since transmission is prohibited by the prohibiting unit, and when the elapsed time reaches a predetermined value set in advance, communication with the non-common protocol is terminated. The communication system according to claim 1, wherein the prohibition of transmission is canceled after the determination.

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