JP2012204934A - Communication device and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent failure to receive data to be received in a predetermined communication period even if a transmission error occurs.SOLUTION: There is provided an HV-ECU comprising: a communication module configured to perform, when a transmission error is detected in data, a retransmission process of the data; and a retransmission control module configured to prohibit, when the number of transmission errors detected in a predetermined communication period exceeds a transmission stop determination threshold value, a retransmission process in the communication period, and to release prohibition of the retransmission process when the communication period ends and the next communication period starts.

Description

  The present invention relates to a communication device and a communication system that performs communication between the communication devices.

  Conventionally, CAN (Controller Area Network) communication is known as a communication method between electronic control units such as an engine ECU (Electronic Control Unit) and a motor ECU. The CAN communication is used to transmit various data transmitted and received between the electronic control units using a communication line called a CAN bus, and is widely used as a low-cost and highly flexible communication method.

  The CAN communication employs a so-called multi-master system in which each electronic control unit transmits data at an arbitrary timing without determining a master-slave relationship such as a master or a slave. Here, when the multi-master method is adopted, data may be simultaneously transmitted from a plurality of electronic control units to the CAN bus, but a plurality of data cannot exist simultaneously on one CAN bus. For this reason, in CAN communication, priorities are set for each data, and communication arbitration is performed in which transmission is performed in order from data with higher priorities, thereby avoiding communication collisions.

  In CAN communication, when a data transmission error occurs, such data retransmission processing is performed. Further, in recent years, a technique for stopping a retransmission process when the retransmission process is repeated for a predetermined time is also known. For example, in the technique described in Patent Document 1, retransmission processing is repeated until a transmission error continues for a predetermined time, and when the predetermined time elapses, the transmission error is a permanent error due to a failure of the electronic control unit or the like. And the transmission of all data including retransmission data is stopped.

JP 2010-147590 A

  However, in the above-described prior art, when the electronic control units repeat transmission / reception of data at a predetermined communication cycle, the retransmission process is repeated so that reception of data to be received within the communication cycle is within the communication cycle. There was a risk of a situation that could not be performed.

  In particular, if the priority of data that has caused a transmission error is high, data having a lower priority than such data is not transmitted while the retransmission of the data is repeated. For this reason, there is a high possibility that a state in which low priority data cannot be transmitted within the communication cycle will occur.

  The disclosed technology has been made to solve the above-described problems caused by the prior art, and can prevent data to be received in a predetermined communication cycle even when a transmission error occurs. An object of the present invention is to provide a communication device and a communication system.

  The present application is a communication device in a communication system in which a plurality of communication devices transmit and receive data at a predetermined communication cycle, and communication in the communication system is performed by a communication method in which transmission from a plurality of devices cannot be performed simultaneously. When a transmission error of the data is detected, a retransmission means for performing a retransmission process of the data, and a detection error count or duration time detected within one period in the communication period A retransmission control means for prohibiting the retransmission processing in the communication cycle when the threshold is exceeded, and releasing the prohibition of the retransmission processing when the communication cycle ends and the next communication cycle starts. It is characterized by that.

  According to the present application, even when a transmission error occurs, it is possible to prevent the occurrence of a state in which data that should be received in a predetermined communication cycle cannot be received.

FIG. 1 is a diagram showing an outline of a communication method according to the present application. FIG. 2 is a diagram illustrating a configuration example of the communication system according to the first embodiment. FIG. 3 is a block diagram showing configurations of the HV-ECU and the motor ECU. FIG. 4 is a diagram illustrating an example of a frame configuration of frame data. FIG. 5 is a diagram illustrating an example of a correspondence relationship between data to be transmitted within a communication cycle and a start ID. FIG. 6 is a diagram illustrating an operation example of the HV-ECU and the motor ECU. FIG. 7 is a diagram illustrating an example of data output processing based on the CAN protocol. FIG. 8 is a diagram illustrating an operation example of the communication unit and the retransmission control unit. FIG. 9 is a diagram illustrating an example of threshold value determination processing. FIG. 10 is a timing chart showing an example of communication timings of the HV-ECU and the motor ECU in a predetermined communication cycle. FIG. 11 is a flowchart (part 1) illustrating the processing procedure of the transmission process. FIG. 12 is a flowchart (part 2) illustrating the processing procedure of the transmission process. FIG. 13 is a diagram illustrating an example of a retransmission control process according to the second embodiment. FIG. 14 is a block diagram illustrating configurations of the HV-ECU and the motor ECU according to the third embodiment. FIG. 15 is a diagram (part 1) illustrating an operation example of the retransmission control unit and the abnormality detection unit. FIG. 16 is a diagram (part 2) of an operation example of the retransmission control unit and the abnormality detection unit. FIG. 17 is a diagram illustrating an example of a count pattern of the abnormality determination counter. FIG. 18 is a diagram (part 3) of an operation example of the retransmission control unit and the abnormality detection unit. FIG. 19 is a flowchart illustrating the processing procedure of the transmission processing according to the third embodiment. FIG. 20 is a flowchart (part 1) illustrating the processing procedure of the abnormality determination process. FIG. 21 is a flowchart (part 2) illustrating the processing procedure of the abnormality determination processing.

  Exemplary embodiments of a communication apparatus and a communication system according to the present invention will be described below in detail with reference to the accompanying drawings. First, prior to detailed description of the embodiment, an outline of a communication method according to the present application will be described with reference to FIG. FIG. 1 is a diagram showing an outline of a communication method according to the present application.

  In the conventional communication method, when the first communication device and the second communication device transmit and receive data at a predetermined communication cycle, if a transmission error occurs and the retransmission process is repeated, the data is received within the communication cycle. There is a possibility that a state in which the data to be received cannot be received within the communication cycle may occur.

  In particular, if the priority of data that has caused a transmission error is high, data having a lower priority than such data is not transmitted while the retransmission of the data is repeated.

  For example, in a communication method such as CAN communication in which transmission from a plurality of devices cannot be performed at the same time, in a communication device that transmits a high priority data and generates a transmission error, the transmission error occurs more than the data in which the transmission error occurs. In other communication devices connected to the same communication bus, the communication bus is occupied, so that the transmission error is lower than the data in which the transmission error has occurred. Priority data cannot be transmitted. For this reason, there is a high possibility that a state in which low priority data cannot be transmitted within the communication cycle will occur.

  Therefore, in the communication method according to the present application, when the number of detections of transmission errors detected within one cycle in the communication cycle exceeds the first threshold, retransmission processing in the communication cycle is prohibited, and the communication cycle is When the next communication cycle is started after completion, the prohibition of retransmission processing is canceled.

  As shown in FIG. 1, in the communication method according to the present application, when a data transmission error is detected (see (1) in FIG. 1), the data is retransmitted (see (2) in FIG. 1). In the communication method according to the present application, when the number of transmission errors detected in the current communication cycle exceeds the first threshold (see (3) in FIG. 1), retransmission processing is prohibited ((4) in FIG. 1). reference).

  Furthermore, in the communication method according to the present application, for example, when the next communication cycle is started, the retransmission processing prohibition state is canceled (see (5) in FIG. 1). As a result, the retransmission processing prohibition state is applied only in the current communication cycle.

  Thus, in the communication method according to the present application, when a data transmission error is detected, the data is retransmitted, and the number of detections of the transmission error detected within one cycle in the predetermined communication cycle is the first. When the threshold value is exceeded, the retransmission processing in the communication cycle is prohibited, and the prohibition of the retransmission processing is canceled when the communication cycle ends and the next communication cycle starts.

  That is, in the communication method according to the present application, if the number of transmission error detections within one cycle exceeds the first threshold, it is determined that there is a possibility that a problem may occur in transmission of other data, and retransmission processing is prohibited. It was. Thereby, it is possible to prevent data reception from being hindered by repetition of retransmission processing.

  However, this determination is not for determining a permanent error such as a failure of the communication apparatus, but for determining that received data is not lost. For this reason, the retransmission process is canceled in the next communication cycle.

  Therefore, according to the communication method according to the present application, even if a transmission error occurs, it is possible to prevent data to be received in a predetermined communication cycle.

  FIG. 1 shows an example in which retransmission processing is prohibited when the number of transmission error detections exceeds the first threshold. However, the present invention is not limited to this. The retransmission process may be prohibited when the threshold value is exceeded.

  In the communication method according to the present application, the first threshold value may be dynamically changed according to at which timing of the communication cycle a transmission error is detected. For example, the first threshold value can be determined based on the remaining time of the communication cycle and the time required to receive all the remaining data. This point will be described later.

  Below, the Example about the communication apparatus and communication system to which the communication method which concerns on this application is applied is described in detail. In the following embodiments, a communication system between in-vehicle ECUs will be described as an example of a communication system. However, the communication method according to the present application is not limited to this. It is also applicable to the system.

  In the following, an HV-ECU (Hybrid Vehicle-ECU) that controls the powertrain ECU is an example of a first communication device, and a motor ECU that is one of the powertrain ECUs is an example of a second communication device. Will be described.

  First, a configuration example of a communication system according to the first embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating a configuration example of the communication system according to the first embodiment.

  As shown in FIG. 2, in the communication system according to the present embodiment, the HV-ECU 1 and the motor ECU 2 are connected to each other via a CAN bus. The CAN bus is a two-wire communication line including a CAN_Hi line and a CAN_Lo line. A motor 3 is connected to the motor ECU 2.

  In such a communication system, the master node HV-ECU 1 performs overall control of the motor 3 and the engine in cooperation with various ECUs provided in the vehicle such as the motor ECU 2, and the motor ECU 2 that is the slave node Specific control of the motor 3 is performed according to a command from the HV-ECU 1.

  For example, the HV-ECU 1 transmits the torque command value of the motor 3 to the motor ECU 2 via the CAN bus. When the motor ECU 2 receives the torque command value from the HV-ECU 1 via the CAN bus, the motor ECU 2 controls the motor 3 based on the received torque command value. Further, the motor ECU 2 transmits the control result for the motor 3 to the HV-ECU 1. Such a series of processing is performed within a predetermined communication cycle determined in advance.

  As described above, the communication device of the present application is provided for a control device that needs to receive a predetermined amount of data within one cycle of the communication cycle as data used for a predetermined calculation process performed in a predetermined control cycle. It is done.

  Here, the “control cycle” is a processing cycle of a predetermined control process performed by the first communication device, and here, the first communication device and the first communication device required for the predetermined control process It is also a period during which communication processing performed between the second communication devices needs to be completed. The “communication processing cycle” is a processing cycle of processing performed for communication within the communication cycle. In the following, an example in which the control cycle is the same as the communication cycle will be described, but the control cycle may be different from the communication cycle and the length of the cycle or the start timing.

  The HV-ECU 1 includes a CAN transceiver 11 and a microcomputer 12. Similarly, the motor ECU 2 includes a CAN transceiver 21 and a microcomputer 22. Here, the CAN transceivers 11 and 21, the hardware units in the microcomputers 12 and 22, and the hardware such as the CAN bus are obtained by diverting CAN communication hardware as they are. That is, the communication system according to the present embodiment can be realized using an inexpensive configuration, similar to CAN communication.

  As shown in FIG. 2, the HV-ECU 1 is connected to various ECUs provided in a vehicle such as the engine ECU 4 and the battery ECU 5 (for example, the engine ECU 4 and the battery ECU 5) separately from the CAN bus for connecting to the motor ECU 2 (for example, , CAN bus).

  2, only the HV-ECU 1 and the motor ECU 2 are connected to the CAN bus that connects the HV-ECU 1 and the motor ECU 2. However, the CAN bus has three or more communication devices. It is also possible to connect (ECU).

  Next, the configuration of the HV-ECU 1 and the motor ECU 2 will be described with reference to FIG. In FIG. 3, only components necessary for explaining the characteristics of the HV-ECU 1 and the motor ECU 2 are shown, and descriptions of general components are omitted.

  As shown in FIG. 3, the HV-ECU 1 includes a CAN transceiver 11 and a microcomputer 12. The microcomputer 12 includes a communication unit 121, a transmission buffer 122, a reception buffer 123, a register 126, a platform 124, and a control unit 125. The control unit 125 includes a data storage processing unit 125a, a reception completion processing unit 125b, and a retransmission control unit 125c.

  The motor ECU 2 includes a CAN transceiver 21 and a microcomputer 22. The microcomputer 22 includes a communication unit 221, a transmission buffer 222, a reception buffer 223, a platform 224, and a control unit 225. The control unit 225 includes an ID reading unit 225a and a data storage processing unit 225b.

  First, the configuration of the HV-ECU 1 will be described. The CAN transceiver 11 is an interface IC (Integrated Circuit) between the microcomputer 12 and the CAN bus. Specifically, the CAN transceiver 11 outputs data generated by the microcomputer 12 to the CAN bus and outputs data input from the CAN bus to the microcomputer 12.

  The microcomputer 12 is a microcomputer that controls communication with the motor ECU 2 according to the CAN protocol. Here, in the microcomputer 12, the communication unit 121, the transmission buffer 122, the reception buffer 123, and the register 126 are configured by hardware, and the platform 124 and the control unit 125 are configured by software.

  The communication unit 121 is a hardware unit that executes data transmission / reception according to the CAN protocol. Specifically, when data is stored in the transmission buffer 122, the communication unit 121 outputs the data stored in the transmission buffer 122 to the CAN bus via the CAN transceiver 11 according to the CAN protocol. In addition, when receiving data from the CAN transceiver 11, the communication unit 121 stores the received data in the reception buffer 123. A specific example of the data transmission process (communication arbitration) executed based on the CAN protocol will be described later with reference to FIG.

  The communication unit 121 is also a processing unit that performs retransmission processing of data when a data transmission error occurs. Specifically, the communication unit 121 includes a transmission register 121a that temporarily holds data output to the CAN bus, and a reception register 121b that temporarily holds data input from the CAN bus.

  The retransmission process executed by the communication unit 121 will be described. This retransmission process is a process that is automatically performed by the communication unit 121 according to the CAN protocol.

  When the data stored in the transmission buffer 122 is output to the CAN bus, the communication unit 121 acquires the data output to the CAN bus from the CAN bus and stores the data in the reception register 121b.

  Further, the communication unit 121 refers to the data stored in the reception register 121b and checks whether or not the data output to the CAN bus has been normally performed. When the data output to the CAN bus is not normally performed, it is detected that a transmission error has occurred, and the data stored in the transmission register 121a, that is, the data subject to the transmission error is displayed. Output to the CAN bus again.

  The communication unit 121 also performs a process of turning on the transmission error flag of the register 126 when a transmission error is detected, and performs a process of turning off the transmission error flag when the retransmission process is performed. Perform together.

  The register 126 is a temporary storage unit that holds various status flags referred to by the control unit 125. For example, the register 126 holds a transmission error flag indicating that a transmission error has occurred, a final flag indicating that it is the last communication processing cycle in the communication cycle, a transmission stop flag indicating that the transmission is stopped, and the like. .

  The transmission buffer 122 is a hardware unit that temporarily stores data to be transmitted to another ECU (here, the motor ECU 2). The reception buffer 123 is a hardware unit that temporarily stores data received from another ECU (here, the motor ECU 2).

  As the CAN transceiver 11, the communication unit 121, the transmission buffer 122, the reception buffer 123, and the register 126, a CAN transceiver, a communication unit, a transmission buffer, a reception buffer, and a register that are used in conventional CAN communication can be used. It is not limited to this. That is, a transceiver, a communication unit, a transmission buffer, a reception buffer, and a register dedicated to the communication system according to the present embodiment may be used.

  The platform 124 is a processing unit that performs processing of passing data generated by the control unit 125 that is a software unit to the transmission buffer 122 that is a hardware unit. The platform 124 is also a processing unit that performs processing for passing data received from the reception buffer 123 that is a hardware unit to the control unit 125 that is a software unit.

  The control unit 125 is, for example, a CPU (Central Processing Unit), and is a software unit that executes processing related to communication with the motor ECU 2. The control unit 125 particularly includes a data storage processing unit 125a, a reception completion processing unit 125b, and a retransmission control unit 125c.

  The data storage processing unit 125 a is a processing unit that stores transmission data to the motor ECU 2 in the transmission buffer 122 via the platform 124. Specifically, the data storage processing unit 125a divides data to be transmitted to the motor ECU 2 into predetermined blocks (for example, every four frames), and stores the divided data in the transmission buffer 122 for each communication processing cycle.

  In particular, the data storage processing unit 125a stores, in the transmission buffer 122, data including a start ID indicating the start of the communication cycle at the start of a predetermined communication cycle. Here, a frame configuration of frame data transmitted and received in the communication system according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of a frame configuration of frame data.

  As shown in FIG. 4, the frame data includes, for example, data information of 0 to 8 bytes. The frame data includes an ID. The ID is, for example, a value represented by 11 bits. In the conventional CAN communication, the ID is information indicating the type of data and information indicating the priority of data in communication arbitration.

  The ID included in the frame data is normal data, the type of this data such as “torque command value” and “motor rotational speed”, “normal ID” indicating the priority order of this data, and the priority order of the data. In addition, there are two types of IDs: “start ID” indicating the start of a predetermined communication cycle and “control ID” including control information such as “inspection ID” instructing mode transition to the inspection mode.

  That is, in the communication system according to the present embodiment, a “control ID” is provided as an ID used in conventional CAN communication, and a “start ID” is provided as one of the “control ID”. As described above, the “start ID” is information indicating the priority order of data and is information indicating the start of a predetermined communication cycle.

  In addition, it is good also as providing control ID provided to control information separately from normal ID provided to normal data. The control ID in such a case need not be the same number of bits (here, 11 bits) as the ID used in the conventional CAN communication, and may be expressed by a smaller number of bits.

  In addition, here, the ID is given information indicating the start of a predetermined communication cycle. However, the present invention is not limited to this. For example, command information indicating the start of a predetermined communication cycle is stored as data. It is good. In such a case, the ID is an ID that represents some data in the normal ID, and only the data content may be replaced with the command information, or an unused ID may be used as the ID for transmitting the command information.

  In addition, when storing data in the transmission buffer 122, the data storage processing unit 125a refers to the transmission stop flag in the register 126, and stores data in the transmission buffer 122 if the transmission stop flag is off. . On the other hand, the data storage processing unit 125a does not store data in the transmission buffer 122 when the transmission stop flag is on. In such a case, data transmission from the HV-ECU 1 is not performed.

  Returning to FIG. 3, the description of the control unit 125 of the HV-ECU 1 will be continued. The reception completion processing unit 125b is a processing unit that performs reception completion processing when final frame data within a predetermined communication cycle is received from the motor ECU 2.

  For example, when the final frame data is received from the motor ECU 2, the reception completion processing unit 125 b performs a sum check and determines whether all the frame data has been normally received from the motor ECU 2.

  The retransmission control unit 125c is a processing unit that prohibits retransmission processing in a communication cycle when the number of transmission error detections in a predetermined communication cycle exceeds a first threshold. The retransmission control unit 125c also performs a process of canceling the prohibition of the retransmission process when the communication period in which the retransmission process is prohibited ends and the next communication period starts.

  Specifically, the retransmission control unit 125c counts up the transmission determination counter every time the transmission error flag of the register 126 is turned on. When the count value of the transmission determination counter exceeds a first threshold (hereinafter referred to as “transmission stop determination threshold”), a retransmission prohibition instruction is notified to the communication unit 121, and the retransmission process of the communication unit 121 is performed. Turn off the function. Also, when the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition command, the retransmission control unit 125c returns the count value of the transmission determination counter to zero.

  Further, the retransmission control unit 125c turns on the transmission stop flag of the register 126 when the count value of the transmission determination counter exceeds the transmission stop determination threshold. When the transmission stop flag is turned on, the data storage processing unit 125 a stops storing data in the transmission buffer 122.

  In addition, when the last communication processing cycle in the communication cycle ends (that is, when the communication cycle ends), the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition release command, and the retransmission processing function of the communication unit 121 Turn on. Thereby, the retransmission prohibition state of the communication unit 121 is canceled. In addition, the retransmission control unit 125c turns off the transmission stop flag of the register 126 when the last communication processing cycle in the communication cycle ends. As a result, the communication unit 121 resumes data storage in the transmission buffer 122.

  A specific operation example of the retransmission control process performed by the retransmission control unit 125c will be described later with reference to FIG.

  The retransmission control unit 125c also performs a threshold determination process for determining a transmission stop determination threshold based on a transmission error detection timing within the communication period. With this threshold value determination process, it is possible to continue the retransmission process for as long as possible and as many times as possible while securing the time necessary for receiving the remaining data. Details of the threshold value determination process will be described later with reference to FIG.

  In FIG. 3, only the data storage processing unit 125a, the reception completion processing unit 125b, and the retransmission control unit 125c are shown as processing units included in the control unit 125. However, the control unit 125 uses data received from the motor ECU 2. Other processing units such as an arithmetic processing unit that performs predetermined calculations may be provided.

  Next, the configuration of the motor ECU 2 will be described. Note that the hardware of the motor ECU 2, specifically, the CAN transceiver 21, the communication unit 221, the transmission buffer 222, and the reception buffer 223 have the same configuration as the hardware of the HV-ECU 1, and thus description thereof is omitted here. . Further, the platform 224 is also a processing unit similar to the platform 124 of the HV-ECU 1, and a description thereof is omitted here.

  The motor ECU 2 may include a transmission register 121a, a reception register 121b, a register 126, and the like included in the HV-ECU 1.

  The control unit 225 of the motor ECU 2 is, for example, a CPU, and is a software unit that executes processing related to communication with the HV-ECU 1. The control unit 225 includes an ID reading unit 225a and a data storage processing unit 225b. Note that the control unit 225 may include a reception completion processing unit 125b and a retransmission control unit 125c included in the control unit 125 of the HV-ECU 1.

  The ID reading unit 225a is a processing unit that reads the ID of data stored in the reception buffer 223, and performs processing of passing the start ID to the data storage processing unit 225b when the read ID is the start ID. It is assumed that which ID is the start ID is determined in advance.

  The data storage processing unit 225b is a processing unit that stores transmission data to the HV-ECU 1 in the transmission buffer 222 via the platform 224. When the data storage processing unit 225b receives the start ID from the ID reading unit 225a, the data storage processing unit 225b transmits the data corresponding to the received start ID, that is, the data to be transmitted within a predetermined communication cycle in a batch instead of every predetermined block. Processing to store in the buffer 222 is performed.

  Here, the correspondence between the data to be transmitted within the communication cycle and the start ID will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of a correspondence relationship between data to be transmitted within a communication cycle and a start ID.

  As shown in FIG. 5, the start ID is associated with data to be transmitted within the communication cycle in advance. In the example illustrated in FIG. 5, “data A” is associated with the start ID “1111 ***”, and “data B” is associated with the start ID “1122 ***”. Note that “data A” and “data B” represent data types, not data values themselves.

  For example, when the data storage processing unit 225b receives the start ID “1111 ***” indicating the start of the process of changing the torque command value, the data storage processing unit 225b acquires the torque value of the motor 3 as “data A” and batches it. Store in the transmission buffer 222.

  In FIG. 3, only the ID reading unit 225a and the data storage processing unit 225b are shown as the processing units included in the control unit 225, but the control unit 225 may include other control units. For example, the control unit 225 receives a final frame data from the HV-ECU 1, a reception completion processing unit that executes a reception completion process, a motor control unit that controls the motor 3 in accordance with a control command received from the HV-ECU 1, and the like. May be provided.

  Next, operation examples of the HV-ECU 1 and the motor ECU 2 will be described. FIG. 6 is a diagram illustrating an operation example of the HV-ECU 1 and the motor ECU 2. 6A shows an operation example during the data transmission process of the HV-ECU 1, and in FIG. 6B, the motor ECU 2 receives the data from the HV-ECU 1, and sends the corresponding data to the transmission buffer. An operation example until the data is stored in 222 is shown.

  As shown in FIG. 6A, the HV-ECU 1 starts data transmission to the motor ECU 2 when a new communication cycle arrives. Specifically, in the HV-ECU 1, the data storage processing unit 125a stores the divided data obtained by dividing the data to be transmitted within the communication cycle every four frames in the transmission buffer 122 for each communication processing cycle of the own device.

  In the HV-ECU 1, each time the divided data is stored in the transmission buffer 122, the communication unit 121 outputs the divided data to the CAN bus via the CAN transceiver 11.

  Here, the start frame data indicating the start of the communication cycle is included in the first frame data of the divided data transmitted from the HV-ECU 1 to the motor ECU 2 first. Here, the data to be transmitted within the communication cycle is divided every four frames, but the data division unit need not be four frames.

  When the current communication cycle is started, the HV-ECU 1 transmits information related to the motor state such as the motor rotation number sent from the motor ECU 2 in the previous communication cycle (control cycle), or another bus. The amount of torque that must be output by the motor or engine based on various information related to vehicle control, such as the driver's accelerator depressing state (torque amount required by the driver), battery charging state, etc. (Torque command value) etc. are calculated.

  On the other hand, as shown in FIG. 6B, when the motor ECU 2 receives a reception interrupt from the hardware unit, the ID reading unit 225a reads the ID included in the divided data received from the HV-ECU 1. If the read ID includes a start ID, the ID reading unit 225a passes the start ID to the data storage processing unit 225b. Here, it is assumed that the start ID is “1111 ***”.

  When the data storage processing unit 225 b receives the start ID from the ID reading unit 225 a, the data storage processing unit 225 b acquires data corresponding to the received start ID, and stores the acquired data in the transmission buffer 222. Here, since the start ID “1111 ***” is received, the data storage processing unit 225b acquires the data A corresponding to the start ID “1111 ***” from the motor 3 or the like (see FIG. 5). The data A is stored in the transmission buffer 222.

  When the motor ECU 2 receives the start ID from the HV-ECU 1, the motor ECU 2 obtains the motor state (such as the torque command value sent from the HV-ECU 1 in the previous communication cycle). Among the information related to the state of the motor after the control is performed and the calculation result in the motor ECU 2 in the previous communication cycle, data that needs to be transmitted to the HV-ECU 1 is set in the transmission buffer 222.

  Next, an operation example of processing in which the communication unit 221 of the motor ECU 2 outputs the data stored in the transmission buffer 222 to the CAN bus according to the CAN protocol will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of data output processing based on the CAN protocol. Here, an example in which the data A stored in the transmission buffer 222 is composed of n frame data is shown.

  As shown in FIG. 7, the communication unit 221 of the motor ECU 2 outputs data to the CAN bus while appropriately performing communication arbitration with the HV-ECU 1. Specifically, when the frame data is stored in the transmission buffer 222, the communication unit 221 checks whether or not the CAN bus is in an empty state. The stored data A is output to the CAN bus frame by frame. In the case shown in FIG. 7, frame data 1 to 4 are output to the CAN bus.

  Subsequently, when the communication unit 221 of the motor ECU 2 tries to output the frame data 5 to the CAN bus, it is assumed that a CAN bus contention has occurred with the HV-ECU 1. In such a case, the communication unit 221 gives priority to the data output of the HV-ECU 1, and outputs the frame data 5 to the CAN bus after the CAN becomes empty. This is because the priority of data from the motor ECU 2 is set lower than the priority of data from the HV-ECU 1.

  As described above, in the communication system according to the first embodiment, the data storage processing unit 125a of the HV-ECU 1 stores the data including the start ID indicating the start of the predetermined communication cycle in the transmission buffer 122, and the HV-ECU 1 The communication unit 121 outputs the data stored in the transmission buffer 122 to the CAN bus according to the CAN protocol.

  Further, the communication unit 221 of the motor ECU 2 stores the data input from the CAN bus in the reception buffer 223 and outputs the data stored in the transmission buffer 222 to the CAN bus according to the CAN protocol. When the processing unit 225b includes a start ID in the data stored in the reception buffer 223, the processing unit 225b stores data corresponding to the start ID and data to be transmitted within a predetermined communication period in the transmission buffer 222. The processing is started, and when the transmission buffer 222 becomes empty, data to be transmitted is sequentially stored.

  Specifically, when the frame data is stored in the transmission buffer 222, the communication unit 221 of the motor ECU 2 continuously outputs each frame data stored in the transmission buffer 222 to the CAN bus. When a CAN bus contention with the HV-ECU 1 occurs, priority is given to data output from the HV-ECU 1.

  Thus, in the communication system according to the first embodiment, when the transmission processing of the HV-ECU 1 and the motor ECU 2 occurs simultaneously, the transmission processing of the HV-ECU 1 has priority over the transmission processing of the motor ECU 2.

  Here, the communication in the communication system is assumed to be CAN communication in which communication is performed in accordance with the CAN protocol. However, the communication is not limited to this, and transmission from a plurality of communication devices is performed simultaneously as in CAN communication. Any communication method that does not allow communication is acceptable.

  Next, operation examples of the communication unit 121 and the retransmission control unit 125c will be described with reference to FIG. FIG. 8 is a diagram illustrating an operation example of the communication unit 121 and the retransmission control unit 125c. 8A shows an operation example of the communication unit 121 and the retransmission control unit 125c, and FIG. 8B shows a retransmission control pattern of the retransmission control unit 125c.

  As shown in FIG. 8A, it is assumed that the communication unit 121 and the retransmission control unit 125c each detect a transmission error (see (1) in FIG. 8A). Specifically, the communication unit 121 detects a transmission error by referring to data held in the reception register 121b, and the retransmission control unit 125c detects a transmission error by referring to the transmission error flag of the register 126. To do.

  When detecting a transmission error, the communication unit 121 performs a retransmission process (see (2) in FIG. 8A). Further, when detecting a transmission error, the retransmission control unit 125c performs a count process of a transmission stop determination counter (see (3) of (A) in FIG. 8). In FIG. 8A, it is assumed that transmission errors occur continuously and retransmission processing and counting processing are continuously performed.

  Here, if the count value of the transmission stop determination counter exceeds the transmission stop determination threshold (see (4) of FIG. 8A), the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition instruction. (See (5) in FIG. 8). Thereby, since the retransmission function is turned off, the retransmission process is stopped.

  The retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition release command at the start of the next communication cycle after the last communication processing cycle in the current communication cycle ends ((( (See (6) of A)). As a result, the retransmission function is turned on. That is, the retransmission prohibition state of the communication unit 121 is maintained only in the current communication cycle.

  Incidentally, FIG. 8A illustrates an example in which retransmission processing is prohibited when the count value of the transmission stop determination counter (that is, the number of detections and the detection time of transmission errors) exceeds the transmission stop determination threshold. However, the retransmission control unit 125c may not only prohibit the retransmission process but also stop the normal data transmission process.

  That is, as shown in FIG. 8B, the retransmission control process performed by the retransmission control unit 125c includes a pattern that prohibits only the retransmission process, a retransmission process, and a normal data transmission process (hereinafter simply referred to as “transmission process”). ") And a pattern that prohibits both. The control unit 125 of the HV-ECU 1 can arbitrarily change these retransmission control patterns.

  Note that the retransmission control unit 125c performs only a process of notifying the communication unit 121 of a retransmission prohibition instruction when only the retransmission process is prohibited (in the case of retransmission control pattern 1). On the other hand, when the retransmission control unit 125c prohibits retransmission processing and transmission processing (in the case of retransmission control pattern 2), the retransmission control unit 125c turns on the processing for notifying the communication unit 121 of a retransmission prohibition command and the transmission stop flag of the register 126. Perform the process.

  Further, when prohibiting retransmission processing and transmission processing, processing for deleting the frame data to be prohibited from the transmission buffer 122 is performed as necessary.

  Next, threshold value determination processing by the retransmission control unit 125c will be described with reference to FIG. FIG. 9 is a diagram illustrating an example of threshold value determination processing. FIG. 9A shows an example of the threshold determination process in the retransmission control pattern 2, and FIG. 9B shows an example of the threshold determination process in the retransmission control pattern 1.

  As shown in FIG. 9A, when a transmission error is detected for the first time in the communication cycle, the retransmission control unit 125c receives all the remaining data (unreceived data) that need to be received in the predetermined communication cycle. The transmission stop determination threshold value is determined based on the time (T1) required for the transmission and the remaining time (T2) of the predetermined communication cycle.

  For example, the retransmission control unit 125c calculates the allowable number of transmission error detections by dividing the time obtained by subtracting T1 from T2 by the transmission error detection time interval (time required for one transmission process or retransmission process). The determined number of detections or a time based on the number of detections is determined as a transmission stop determination threshold value.

  As a result, the retransmission control unit 125c can continue the retransmission process for as long as possible while ensuring the time necessary for receiving the remaining data. The HV-ECU 1 knows in advance the number and size of data to be received within the communication cycle and the time required to receive one frame data, and can calculate T2 from these pieces of information. It is also assumed that the transmission error detection time interval is known in advance.

  On the other hand, in the case of retransmission control pattern 1 (when only retransmission processing is prohibited), the retransmission control unit 125c determines the transmission stop determination threshold in consideration of the time (T3) required until all untransmitted data is transmitted. That's fine. For example, the retransmission control unit 125c calculates the allowable number of transmission error detections by dividing the time obtained by subtracting T1 and T3 from T2 by the transmission error detection time interval, and uses the calculated number of detections as the transmission stop determination threshold value. decide.

  As described above, when a data transmission error is detected, the retransmission control unit 125c sets the time required to receive all the remaining data to be received in a predetermined communication cycle and the remaining time of the predetermined communication cycle. Since the transmission stop determination threshold is determined on the basis of this, the retransmission process can be continued for as long as possible while securing the time necessary for receiving the remaining data.

  In (A) and (B) of FIG. 9, a transmission stop determination threshold value is determined such that retransmission processing is repeated until the time obtained by subtracting T1 from T2 or the time obtained by subtracting T1 and T3 from T2 elapses. However, it is not limited to this.

  Specifically, here, the transmission stop determination threshold is determined only assuming that transmission / reception of data is delayed due to retransmission processing, but it is also assumed that transmission / reception of data is delayed due to factors other than retransmission processing. . Therefore, the retransmission control unit 125c may determine the transmission stop determination threshold based on the time obtained by subtracting T1 from T2 or the time obtained by subtracting a predetermined offset time from the time obtained by subtracting T1 and T3 from T2. .

  Next, communication timings within the communication cycle of the HV-ECU 1 and the motor ECU 2 will be described with reference to FIG. FIG. 10 is a timing chart showing an example of communication timings of the HV-ECU 1 and the motor ECU 2 in a predetermined communication cycle.

  Here, in FIG. 10, it is assumed that the communication processing cycle of the HV-ECU 1 and the motor ECU 2 is 1 ms, respectively, and the communication cycle (control cycle) is 8 ms corresponding to 8 communication processing cycles. Further, in FIG. 10, when only the length of the communication processing cycle and the communication cycle are set to the same length without synchronizing the start / end timing of the communication cycle between the HV-ECU 1 and the motor ECU 2. An example is shown. FIG. 10 shows the case of the retransmission control pattern 2 shown in FIG.

  As shown in FIG. 10, when the communication cycle arrives, the control unit 125 of the HV-ECU 1 latches (holds) data acquired in the previous communication cycle and SUM of data scheduled to be transmitted in the current communication cycle. Processing for calculating a value is performed (see (1a) in FIG. 10).

  Here, the SUM value is a value obtained by adding all the values when information (ID, data, etc.) excluding the SUM value in each frame data is information represented by binary numbers of 0 and 1. is there. The calculated SUM value is added to each frame data.

  Moreover, the control part 125 of HV-ECU1 will store the first division | segmentation data in the transmission buffer 122 among the division | segmentation data of the data transmitted to motor ECU2 after this process is completed (refer (1b) of FIG. 10). Here, the start ID is included in the first frame data of the divided data.

  When the divided data is stored in the transmission buffer 122 of the HV-ECU 1, the communication unit 121 of the HV-ECU 1 outputs the divided data stored in the transmission buffer 122 to the CAN bus (see (1c) in FIG. 10). The divided data output to the CAN bus is input to the communication unit 221 of the motor ECU 2 and stored in the reception buffer 223 by the communication unit 221.

  When the divided data is stored in the reception buffer 223, the control unit 225 of the motor ECU 2 generates a reception interrupt and reads the ID of the divided data stored in the reception buffer 223 (see (2a) in FIG. 10).

  At this time, if the read ID includes the start ID, the control unit 225 of the motor ECU 2 stores a part of the data (divided data) corresponding to the start ID in the transmission buffer 222 ((2b in FIG. 10). )reference).

  When data is stored in the transmission buffer 222, the communication unit 221 of the motor ECU 2 outputs the data stored in the transmission buffer 222 to the CAN bus frame by frame. However, when a CAN bus contention with the HV-ECU 1 occurs, the data output is resumed after waiting for the data output from the HV-ECU 1 to be completed.

  The start ID is embedded in the frame data that is transmitted first from the HV-ECU 1 in a predetermined communication cycle. For this reason, the motor ECU 2 can start processing for storing data to be transmitted within the communication cycle in the transmission buffer 222 at an early stage in the communication cycle.

  As a result, the CAN bus idle time is from when the last frame in the first communication processing cycle from the HV-ECU 1 is output to the CAN bus until the first data from the motor ECU 2 is output to the CAN bus. It can be surely prevented from occurring.

  Here, it is assumed that a frame data transmission error has occurred in the HV-ECU 1 (see (1d) in FIG. 10). In such a case, the communication unit 121 of the HV-ECU 1 continues the retransmission process while a transmission error is detected (see (1e) in FIG. 10). As a result, the same frame data continues to be output to the CAN bus.

  When the number of transmission errors detected exceeds the transmission stop determination threshold, the HV-ECU 1 prohibits retransmission processing by the communication unit 121 until the next communication cycle is started, and also performs normal data transmission. Is prohibited until the communication cycle starts (see (1f) in FIG. 10).

  As a result, the data stored in the transmission buffer 222 of the motor ECU 2 is output to the CAN bus without being hindered by retransmission data from the HV-ECU 1 or normal data. Therefore, HV-ECU 1 can reliably receive data from motor ECU 2 even when a transmission error occurs.

  In addition, the control part 125 of HV-ECU1 will perform a reception completion process, if the last frame of the data which should be received within a communication period is received from motor ECU2 (refer (1g) of FIG. 10). Specifically, in the HV-ECU 1, the reception completion processing unit 125b calculates the SUM value of the data received within the communication cycle, and compares the calculated SUM value with the SUM value transmitted from the HV-ECU 1. Then, a sum check is performed to determine whether or not the SUM value is normal.

  In addition, although the example in the case of performing the SUM check of all the frame data received in one communication period collectively was shown here, not only this but performing a SUM check whenever it receives frame data Also good.

  Moreover, HV-ECU1 will cancel the prohibition state of a resending process and a transmission process, when the next communication period comes. Thereby, the control part 125 of HV-ECU1 starts the transmission process of the data which should be transmitted to motor ECU2 in the next communication cycle.

  That is, the HV-ECU 1 performs a data latch process and a SUM value calculation process (see (1h) in FIG. 10), and among the divided data of the data to be transmitted to the motor ECU 2, the first divided data is sent to the transmission buffer 122. Store (see (1i) in FIG. 10). The divided data stored in the transmission buffer 122 is input to the communication unit 221 of the motor ECU 2 via the CAN bus, and is stored in the reception buffer 223 by the communication unit 221.

  When the divided data is stored in the reception buffer 223, the control unit 225 of the motor ECU 2 generates a reception interrupt, reads the ID of the divided data stored in the reception buffer 223 (see (2c) in FIG. 10), and reads it. If the start ID is included in the received ID, the data corresponding to the start ID is stored in the transmission buffer 222 (see (2d) in FIG. 10). The data stored in the transmission buffer 222 is sequentially output to the CAN bus if the CAN bus is free.

  Note that if the HV-ECU 1 cannot complete reception of data to be received in the current communication cycle due to factors other than the retransmission process, for example, the communication cycle prior to the predetermined communication cycle ( For example, the data received in the previous communication cycle) may be handled as data received in the current communication cycle, and arithmetic processing or the like may be performed.

  As a result, the calculation process is performed in a state where the data received in the current communication cycle and the data received in the previous communication cycle are mixed, thereby preventing an abnormal calculation result from being output.

  Next, a processing procedure of transmission processing executed by the HV-ECU 1 will be described with reference to FIG. FIG. 11 is a flowchart (part 1) illustrating the processing procedure of the transmission process. FIG. 11 shows a processing procedure when the retransmission control pattern is pattern 1 (a pattern for prohibiting only retransmission processing). Further, the transmission processing shown in FIG. 11 is performed every predetermined time (a time shorter than the communication processing cycle).

  As illustrated in FIG. 11, the retransmission control unit 125c determines whether or not it is the start timing of the communication processing cycle (step S101). Specifically, the retransmission control unit 125c determines that it is the start timing of the communication processing cycle by measuring the time from the start timing of the previous communication processing cycle.

  If it is determined that it is the start timing of the communication processing cycle in this process (step S101, Yes), the retransmission control unit 125c determines whether it is the start timing of the communication cycle (step S102). Specifically, the retransmission control unit 125c turns on the final flag of the determination register 126, which is a flag that is turned on when processing the last communication processing cycle in the communication cycle at the start timing of the communication processing cycle. If it is, it is determined that it is the start timing of a new communication cycle.

  In this process, when it is determined that it is the start timing of the communication cycle (step S102, Yes), the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition release command (step S103) and the transmission of the register 126. The stop flag is turned off (step S104). In addition, the retransmission control unit 125c resets the transmission stop determination counter (step S105).

  If the retransmission prohibition instruction is not notified in the previous communication cycle, the processes in steps S103 and S104 may be omitted.

  When the processing of step S105 is completed, or when it is not the start timing of the communication cycle in step S102 (step S102, No), the data storage processing unit 125a extracts transmission data (step S106), and extracts the extracted transmission data. It is set in the transmission buffer 122 (step S107).

  When the processing of step S107 is completed, or when it is not the start timing of the communication processing cycle in step S101 (step S101, No), the retransmission control unit 125c determines whether a transmission error has been detected (step S108). ). Specifically, the retransmission control unit 125c determines that a transmission error has been detected when the transmission error flag of the register 126 is turned on.

  In this process, if it is determined that a transmission error has been detected (Yes at Step S108), the retransmission control unit 125c counts up a transmission stop determination counter (Step S109). In addition, the retransmission control unit 125c determines whether or not the transmission stop flag is turned off (step S110). If it is determined that the transmission stop flag is turned off (step S110, Yes), whether or not the threshold has been determined. Is determined (step S111). If the threshold has not been determined (No at Step S111), threshold determination processing is performed to determine the threshold (Step S112).

  When the process of step S112 is completed, or when the threshold has been determined in step S111 (step S111, Yes), the retransmission control unit 125c determines whether or not the count value of the transmission determination counter exceeds the transmission stop determination threshold. Is determined (step S113).

  When it is determined that the count value of the transmission determination counter exceeds the transmission stop determination threshold (Yes in step S113), the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition instruction (step S114) and a transmission error. Is deleted from the transmission buffer 122 (step S115). Then, the retransmission control unit 125c turns on the transmission stop flag of the register 126 (step S116) and ends the process.

  Note that the retransmission control unit 125c also does not detect a transmission error in step S108 (No in step S108), or if the count value of the transmission determination counter does not exceed the transmission stop determination threshold in step S113 ( In step S113, No), the process ends.

  If the transmission stop flag is not turned off (turned on) in step S110 (No in step S110), the retransmission control unit 125c deletes the data in which the transmission error has occurred from the transmission buffer 122 ( Step S117), the process is terminated.

  Next, the processing procedure of the transmission process when the transmission process is prohibited will be described with reference to FIG. FIG. 12 is a flowchart (part 2) illustrating the processing procedure of the transmission process.

  As illustrated in FIG. 12, the retransmission control unit 125c determines whether it is the start timing of the communication processing cycle (step S201). Specifically, the retransmission control unit 125c determines that it is the start timing of the communication processing cycle by measuring the time from the start timing of the previous communication processing cycle.

  If it is determined that it is the start timing of the communication processing cycle in this process (step S201, Yes), the retransmission control unit 125c determines whether it is the start timing of the communication cycle (step S202). Specifically, the retransmission control unit 125c turns on the final flag of the determination register 126, which is a flag that is turned on when processing the last communication processing cycle in the communication cycle at the start timing of the communication processing cycle. If it is, it is determined that it is the start timing of a new communication cycle.

  In this process, if it is determined that it is the start timing of the communication cycle (step S202, Yes), the retransmission control unit 125c turns off the transmission stop flag of the register 126 (step S203) and resets the transmission stop determination counter (step S203). S204).

  When the process of step S204 is completed or when it is not the start timing of the communication cycle in step S202 (step S202, No), the data storage processing unit 125a determines whether or not the transmission stop flag is turned off (step S202). Step S205).

  If it is determined that the transmission stop flag is turned off in this process (step S205, Yes), the data storage processing unit 125a extracts the transmission data (step S206) and sets the extracted transmission data in the transmission buffer 122 (step S206). Step S207).

  When the processing of step S207 is completed, if the transmission stop flag is not turned off in step S205 (step S205, No), or if it is not the start timing of the communication processing cycle in step S201 (step S201, No), retransmission The controller 125c determines whether a transmission error has been detected (step S208). Specifically, the retransmission control unit 125c determines that a transmission error has been detected when the transmission error flag of the register 126 is turned on.

  In this process, if it is determined that a transmission error has been detected (step S208, Yes), the retransmission control unit 125c counts up a transmission stop determination counter (step S209).

  Also, the retransmission control unit 125c determines whether or not the transmission stop flag is turned off (step S210), and if it is determined that the transmission stop flag is turned off (step S210, Yes), whether or not the threshold has been determined. Is determined (step S211). If the threshold value has not been determined (No at Step S211,), the threshold value determination process is performed to determine the threshold value (Step S212).

  When the process of step S212 is completed, or when the threshold value has been determined in step S211 (step S211, Yes), the retransmission control unit 125c determines whether or not the count value of the transmission stop determination counter exceeds the transmission stop determination threshold value. Is determined (step S213).

  When it is determined that the count value of the transmission stop determination counter has exceeded the transmission stop determination threshold (Yes in step S213), the retransmission control unit 125c deletes all untransmitted data stored in the transmission buffer 122 (step S214). ), The transmission stop flag of the register 126 is turned on (step S215), and the process is terminated.

  The retransmission control unit 125c determines that the transmission error is not detected in Step S206 (No in Step S208), and if the transmission stop flag is not turned off in Step S208 (No in Step S210), the transmission determination in Step S213. Even when the count value of the counter does not exceed the transmission stop determination threshold value (No in step S213), the process ends.

  As described above, in the first embodiment, when a data transmission error is detected, the communication unit of the HV-ECU performs the data retransmission process, and the retransmission control unit of the HV-ECU performs predetermined communication. When the number of transmission error detections in the period exceeds the transmission stop determination threshold, the retransmission process is prohibited in the communication period, and the retransmission process is prohibited when the communication period ends and the next communication period starts. Was decided to cancel.

  Therefore, even when a transmission error occurs, it is possible to prevent data to be received in a predetermined communication cycle from being missed.

  In the first embodiment described above, an example in which retransmission processing is prohibited when the number of transmission error detections exceeds the transmission stop determination threshold has been described. However, the present invention is not limited to this, and the retransmission control unit 125c is not limited thereto. The transmission processing may be prohibited when the duration of the transmission error exceeds the transmission stop determination threshold. In such a case, for example, as shown in FIG. 9A, the time (T1) required from the remaining time (T2) of the predetermined communication cycle until the remaining data to be received in the predetermined communication cycle is received. ) May be determined as a transmission stop determination threshold value.

  By the way, in the first embodiment described above, there is one transmission stop determination threshold determined by the threshold determination process, and this one transmission stop determination threshold is set regardless of the type of frame data that is the target of the transmission error. Although applied uniformly, it is not restricted to this.

  For example, the transmission stop determination threshold applied to the frame data including the start ID is made sweeter than the transmission stop determination threshold applied to other frame data (that is, the allowable number of transmission error detections is increased). ) Is desirable.

  This is because if the frame data including the threshold ID does not reach the motor ECU 2, the data transmission processing (storage processing of data to be transmitted within the communication cycle in the transmission buffer 222) by the motor ECU 2 is not started. In such a case, although the transmission process is stopped in order to give priority to the reception of data, the HV-ECU 1 will miss all data to be received from the motor ECU 2 within the communication cycle, which is not preferable.

  In the following, a second embodiment in which the transmission stop determination threshold applied to the frame data including the start ID is made different from other frame data will be described. FIG. 13 is a diagram illustrating an example of a retransmission control process according to the second embodiment.

  As illustrated in FIG. 13, when the frame data in which the transmission error has occurred is frame data including the start ID, the retransmission control unit 125 c prohibits the notification timing of the retransmission prohibition instruction (transmission processing and retransmission processing are prohibited. Timing) is determined using the transmission stop determination threshold A.

  For example, when the number of transmission errors detected in the frame data including the start ID exceeds the transmission stop determination threshold A, the retransmission control unit 125c notifies the communication unit 121 of a retransmission prohibition instruction. On the other hand, when the frame data that has caused the transmission error is frame data other than the frame data including the start ID, the retransmission control unit 125c uses the transmission stop determination threshold B for the notification timing of the retransmission prohibition instruction. judge.

  Here, the transmission stop determination threshold A is determined to be larger than the transmission stop determination threshold B. For example, the retransmission control unit 125c calculates a value obtained by dividing a time obtained by subtracting T1 (time required until all unreceived data is received) from T2 (remaining time of a predetermined communication cycle) by a transmission error detection time interval. It is determined as a transmission stop determination threshold A. On the other hand, the retransmission control unit 125c transmits a value obtained by multiplying the time obtained by subtracting T1 from T2 by a predetermined coefficient α (0 <α <1) and dividing the value by the transmission error detection time interval. The stop determination threshold B is determined.

  That is, when a transmission error occurs in the frame data including the start ID, the retransmission control unit 125c continues the retransmission process as much as possible while securing the time necessary for receiving the remaining data. Thereby, possibility that the frame data containing start ID will be transmitted to motor ECU2 can be raised. In other words, the possibility of losing all data to be received from the motor ECU 2 within the communication cycle can be reduced as much as possible.

  In addition, when a transmission error occurs in frame data other than the frame data including the start ID, the retransmission control unit 125c retransmits while securing a longer time than the time necessary for receiving the remaining data. (Retransmission processing is prohibited at an early point). As a result, when data transmission / reception is delayed due to a factor other than the retransmission process, it is possible to prevent the data to be received from being missed within the communication cycle.

  As described above, in the second embodiment, when the retransmission control unit of the HV-ECU exceeds the transmission stop determination threshold when the number of transmission errors detected or the duration of the transmission error is detected within one cycle of the communication cycle, Retransmission processing in the communication cycle is prohibited. Then, the retransmission control unit of the HV-ECU determines that the retransmission process is prohibited as compared with the other data when the data in which the transmission error has occurred is data instructing the motor ECU to start transmission. The transmission stop determination threshold is increased.

  Therefore, even if a transmission error occurs, it is possible to prevent a situation in which data to be received in a predetermined communication cycle cannot be received, and whether the data in which the transmission error has occurred is continued in the subsequent communication. In the case of special data related to how, the transmission can be continued as much as possible by performing transmission as much as possible.

  In particular, when the data in which the transmission error has occurred is data (start ID) instructing the transmission start of the counterpart communication device, the data is displayed by prohibiting retransmission in order to prioritize reception of other data. Can no longer be received.

  Although an example in which the specific ID is the start ID has been described here, the specific ID does not necessarily have to be the start ID, and may be another ID. In addition, here, an example in which the number of transmission error detections is compared with a transmission stop determination threshold is shown, but as in the first embodiment, the retransmission control unit 125c compares the transmission error duration with the transmission stop determination threshold. It is good to do.

  By the way, in the first and second embodiments, in order to prevent the data to be received within the communication period from being missed, if the number of transmission errors detected or the duration exceeds the transmission stop determination threshold within the communication period, transmission of other data is performed. It is determined that there may be a problem in (especially data transmission from another communication apparatus), and retransmission processing in such a communication cycle is prohibited for a predetermined period.

  However, as in the first and second embodiments, if data transmission is temporarily stopped in order to prioritize transmission of other data, a conventional abnormality detection process such as a temporary abnormality (electricity) In the abnormality detection process that determines whether the noise is temporarily mixed) or a permanent abnormality, it is difficult to make an accurate determination, and there is a risk that an appropriate response according to the state of communication at that time may not be possible. There is.

  Specifically, when it is determined that the permanent communication abnormality is based on the number of detections of transmission errors, the transmission process is performed when the transmission process is temporarily stopped as in the first and second embodiments. Distinguishing whether there is no transmission, for example, due to a permanent abnormality in the communication unit or CAN transceiver, or because transmission is prohibited due to a temporary transmission error due to electrical noise, etc. However, unless proper abnormality detection processing is performed, there is a possibility that a permanent communication abnormality cannot be accurately detected.

  Therefore, in the third embodiment, a counter (hereinafter referred to as “abnormality determination counter”) for determining a permanent communication abnormal state (hereinafter referred to as “abnormal state”) is used as a temporary transmission process. It is provided separately from a transmission stop determination counter for determining stop. Hereinafter, Example 3 in such a case will be described.

  First, configurations of the HV-ECU and the motor ECU according to the third embodiment will be described with reference to FIG. FIG. 14 is a block diagram illustrating configurations of the HV-ECU and the motor ECU according to the third embodiment. In the following description, parts that are the same as those already described are given the same reference numerals as those already described, and redundant descriptions are omitted.

  As illustrated in FIG. 14, the control unit 125 ′ of the HV-ECU 1 ′ according to the third embodiment further includes an abnormality detection unit 125 d. The abnormality detection unit 125d is a processing unit that stops subsequent data transmission when the number of transmission error detections over a plurality of communication cycles exceeds an abnormality determination threshold value that is higher than the transmission stop determination threshold value.

  Here, the operation of the abnormality detection unit 125d will be described in comparison with the operation of the retransmission control unit 125c. FIG. 15 is a diagram (part 1) illustrating an operation example of the retransmission control unit 125c and the abnormality detection unit 125d.

  As illustrated in FIG. 15, the retransmission control unit 125c increments the count value of the transmission stop determination counter every time a transmission error is detected. When the transmission error detection count or duration in the communication cycle exceeds the transmission stop determination threshold (see (1) in FIG. 15), data transmission from the communication unit 121 (including retransmission) is temporarily stopped ( (See (2) in FIG. 15).

  In addition, the retransmission control unit 125c resets the count value of the transmission determination counter at the start of the next communication cycle (see (3) in FIG. 15). As a result, in the next communication cycle, the number of transmission error detections is counted from zero. The specific operation of the retransmission control process is as described in the first and second embodiments.

  On the other hand, the abnormality detection unit 125d also counts up the count value of the abnormality determination counter every time a transmission error is detected, similarly to the retransmission control unit 125c. The count value of the abnormality determination counter is not reset even when the count value of the transmission stop determination counter is reset (see (4) in FIG. 15).

  Specifically, the abnormality detection unit 125d temporarily interrupts the counting process of the abnormality determination counter when the data transmission from the communication unit 121 is temporarily stopped by the retransmission control unit 125c. Holds the count value of the counter.

  Then, when the count value of the abnormality determination counter exceeds the abnormality determination threshold (see (5) in FIG. 15), the abnormality detection unit 125d determines that a communication abnormality has occurred, and transmits data from the communication unit 121 ( (Including resending). The abnormality detection unit 125d does not cancel the prohibition of the transmission process even if the communication period in which the communication abnormality is detected and the transmission process is prohibited ends and the next communication period is started (see (6) in FIG. 15).

  When the transmission processing is prohibited, the abnormality detection unit 125d prohibits the retransmission control unit 125c from notifying the retransmission prohibition release command and turning off the transmission stop flag of the register 126. As a result, the transmission stop state is not canceled by the retransmission control unit 125c.

  As described above, the transmission stop determination counter for determining a temporary abnormality and the abnormality determination counter for determining a permanent abnormality are separately provided, and the count process of the abnormality determination counter is performed by the count of the transmission stop counter. It was decided in consideration of the processing status of the transmission stop / restart processing based on the processing. For this reason, it is possible to accurately determine whether the detected abnormality is a temporary abnormality (when electric noise is temporarily mixed) or a permanent abnormality.

  In addition to the transmission stop flag that is turned on / off by the retransmission control unit 125c, a transmission stop flag (abnormal flag) that is turned on / off by the abnormality detection unit 125d may be provided in the register 126. In this case, even if the transmission stop flag is turned off by the retransmission control unit 125c, the data storage processing unit 125a stops storing data in the transmission buffer 122 if the abnormality flag is turned on.

  By the way, in FIG. 15, after the abnormality determination, the subsequent transmission data is stopped. However, in this case, communication is not performed even if the communication system returns to normal due to some factor (for example, when repair is performed). A problem occurs. For this reason, the transmission process may be restored each time an apparatus power source, for example, an IG-SW (ignition switch) attached to a vehicle (not shown) is turned on or off.

  In the following, an example of canceling the transmission processing prohibition state when the IG-SW is turned off will be described with reference to FIG. FIG. 16 is a diagram (part 2) illustrating an operation example of the retransmission control unit 125c and the abnormality detection unit 125d.

  As already described using FIG. 15, when the count value of the abnormality determination counter exceeds the abnormality determination threshold (see (1) in FIG. 16), the abnormality detection unit 125d determines that a communication abnormality has occurred, Data transmission (including retransmission) from the communication unit 121 is prohibited. The state in which the transmission process is prohibited is maintained even if the communication cycle in which the transmission process is prohibited ends and the next communication cycle starts (see (2) in FIG. 16).

  Here, when an abnormality determination is made, for example, a warning lamp or the like notifies the user that an abnormality has occurred. When the user recognizes that an abnormality has occurred, the user brings the vehicle to a dealer or the like for repair. At this time, the IG-SW is turned off to perform repair (see (3) in FIG. 16).

  When the IG-SW is turned off, the abnormality detection unit 125d cancels the prohibition of transmission processing (see (4) in FIG. 16) and resets the abnormality determination counter (see (5) in FIG. 16). Note that the count value of the transmission determination counter is reset at the start of the next communication cycle in which the abnormality determination is made by the retransmission control unit 125c (see (6) in FIG. 16).

  In addition, although FIG. 16 demonstrated the example in the case of canceling | released the prohibition state of a transmission process in response to IG-SW having been turned off, it is not restricted to this, IG-SW has been turned on. As a trigger, the transmission processing prohibition state may be canceled.

  As described above, if the prohibition of the transmission process is canceled at least when the power is turned on or off, the prohibition state of the transmission process can be canceled at an appropriate timing.

  Incidentally, in FIG. 15 and FIG. 16, every time a transmission error is detected, the count value of the abnormality determination counter is counted up. However, the timing for counting up the count value of the abnormality determination counter is limited to this. It is not a thing. For example, every time the retransmission control unit 125c temporarily stops data transmission, the count value of the abnormality determination counter may be incremented.

  Furthermore, the abnormality detection unit 125d may not only count up the count value of the abnormality determination counter, but may count down according to a predetermined condition. Therefore, the count pattern of the abnormality determination counter will be described with reference to FIG. FIG. 17 is a diagram illustrating an example of a count pattern of the abnormality determination counter.

  As illustrated in FIG. 17, the abnormality detection unit 125d may count up the count value of the abnormality determination counter every time a transmission error is detected, for example, similarly to the retransmission control unit 125c (pattern 1 in FIG. 17). ). In such a case, the abnormality detection unit 125d may count down the count value of the abnormality determination counter every time frame data is normally transmitted (pattern 2 in FIG. 17).

  In addition, the abnormality detection unit 125d may increment the count value of the abnormality determination counter every communication cycle in which a transmission error is detected (pattern 3 in FIG. 17). In such a case, the abnormality detection unit 125d does not have to perform the counting process until the next communication cycle comes after the first transmission error in the communication cycle is detected. That is, since the frequency of the count process is reduced as compared with patterns 1 and 2, the processing load can be reduced. Further, the abnormality detection unit 125d may count down the count value of the abnormality determination counter when a transmission error is not detected within the communication cycle (pattern 4 in FIG. 17).

  Further, the abnormality detection unit 125d may count up the count value of the abnormality determination counter when a transmission error is detected and the transmission error is not recovered within the communication cycle (pattern of FIG. 17). 5). In this way, it is possible to exclude the case where a transmission error has occurred but the error has been recovered within the communication cycle from the count-up target.

  In addition, the abnormality detection unit 125d counts down the count value of the abnormality determination counter when a transmission error is not detected within the communication cycle, or when a transmission error is detected but the error is recovered within the communication cycle. (Pattern 6 in FIG. 17). Note that the abnormality detection unit 125d may maintain the count value of the abnormality determination counter without counting down when a transmission error is detected but the error is recovered within the communication cycle.

  Further, as a pattern not shown in FIG. 17, the abnormality detection unit 125d detects whether there is a transmission error and normal transmission of frame data every predetermined time, and normal transmission of frame data after a previous transmission error is detected. If no transmission error has been detected, the count value of the abnormality determination counter is incremented, and if no transmission error has been detected since the normal transmission of frame data was previously detected, the count value of the abnormality determination counter is counted down. You may do it. In this case, it is possible to detect an abnormality according to the duration of each of an abnormal state based on a transmission error and a normal state based on normal transmission of frame data.

  Further, the above-described count-up conditions and count-down conditions are not limited to the combinations described in the respective patterns, and may be combinations of count-up conditions and count-down conditions not included in the above-described patterns.

  Further, the configuration is such that the count-up is performed when there is an abnormality, and the count-down operation is performed when the operation is normal. Further, a counter that counts abnormal states and a counter that counts normal states may be provided separately. In this case, for example, when the counter that counts the normal state exceeds a predetermined threshold, the counter that counts the abnormality is reset.

  Here, pattern 2 in FIG. 17 will be described with reference to FIG. FIG. 18 is a diagram (part 3) of an operation example of the retransmission control unit and the abnormality detection unit. Here, FIG. 18 shows an example in which the transmission state returns to normal before the count value of the abnormality determination counter exceeds the abnormality determination threshold (see (1) in FIG. 18).

  As shown in FIG. 18, the abnormality detection unit 125d counts down the count value of the abnormality determination counter by 1 every time data transmission is normally completed (see (2) in FIG. 18). Then, when the count value of the abnormality determination counter becomes “0”, the abnormality detection unit 125d maintains the count value “0” (see (3) in FIG. 18).

  In this way, if the count value of the abnormality determination counter is counted down according to a predetermined condition, the temporary transmission error detection is accumulated over a long period of time, so that in this abnormal state (permanent abnormal state). It is possible to prevent erroneous determination as being present.

  Note that the abnormality detection unit 125d may increment the count value of the abnormality determination counter every time the retransmission control unit 125c temporarily stops data transmission. In such a case, the abnormality detection unit 125d may count down the count value of the abnormality determination counter when data transmission is not temporarily stopped in the communication cycle.

  Next, a processing procedure of transmission processing according to the third embodiment will be described with reference to FIG. FIG. 19 is a flowchart illustrating the processing procedure of the transmission processing according to the third embodiment.

  As illustrated in FIG. 19, the retransmission control unit 125c determines whether or not the abnormality flag is turned off (step S301). If the abnormality flag is turned off (step S301, Yes), the communication processing cycle starts. It is determined whether it is timing (step S302).

  If it is determined in step S302 that it is the start timing of the communication cycle (step S302, Yes), the retransmission control unit 125c determines whether it is the start timing of the communication cycle (step S303).

  In this process, when it is determined that it is the start timing of the communication cycle (step S303, Yes), the retransmission control unit 125c turns off the transmission stop flag of the register 126 (step S304) and resets the transmission stop determination counter (step S304). S305).

  When the processing of step S305 is completed or when it is not the start timing of the communication cycle in step S303 (step S303, No), the data storage processing unit 125a determines whether or not the transmission stop flag is turned off (step S303). Step S306).

  If it is determined in this process that the transmission stop flag is off (step S306, Yes), the data storage processing unit 125a extracts the transmission data (step S307), and sets the extracted transmission data in the transmission buffer 122 (step S307). Step S308).

  When the processing of step S308 is completed, if the transmission stop flag is not turned off in step S306 (step S306, No), or if it is not the start timing of the communication processing cycle in step S302 (step S302, No), retransmission The control unit 125c determines whether or not a transmission error has been detected (step S309). Specifically, the retransmission control unit 125c determines that a transmission error has been detected when the transmission error flag of the register 126 is turned on.

  In this process, if it is determined that a transmission error has been detected (step S309, Yes), the retransmission control unit 125c counts up a transmission stop determination counter (step S310). Also, the retransmission control unit 125c determines whether or not the transmission stop flag is turned off (step S311), and if it is determined that the transmission stop flag is turned off (step S311, Yes), whether or not the threshold has been determined. Is determined (step S312). If the threshold has not been determined (No at Step S312), the threshold determination process is performed to determine the threshold (Step S313).

  When the process of step S313 is completed, or when the threshold value has been determined in step S312 (Yes in step S312), the retransmission control unit 125c determines whether the count value of the transmission stop determination counter exceeds the transmission stop determination threshold value. Is determined (step S314).

  When it is determined that the count value of the transmission stop determination counter has exceeded the transmission stop determination threshold (step S314, Yes), the retransmission control unit 125c deletes all untransmitted data stored in the transmission buffer 122 (step S315). ), The transmission stop flag of the register 126 is turned on (step S316), and the process is terminated.

  The retransmission control unit 125c determines that the abnormality flag is not turned off in step S301 (step S301, No), and if no transmission error is detected in step S309 (step S309, No), the transmission stop flag in step S311. Is not turned off (step S311, No), and also when the count value of the transmission determination counter does not exceed the transmission stop determination threshold value in step S314 (step S314, No), the process ends.

  Next, a processing procedure related to the abnormality determination process will be described with reference to FIG. FIG. 20 is a flowchart (part 1) illustrating the processing procedure of the abnormality determination process. Note that the abnormality detection unit 125d performs the processing procedure illustrated in FIG. 20 in parallel with the processing procedure illustrated in FIG.

  As illustrated in FIG. 20, the abnormality detection unit 125d determines whether or not the transmission stop flag is turned off (step S401). If the transmission stop flag is turned off (step S401, Yes), the transmission is stopped. It is detected whether an error has been detected (step S402).

  In step S402, when a transmission error is detected (step S402, Yes), the abnormality detection unit 125d counts up the abnormality determination counter (step S403). Subsequently, the abnormality detection unit 125d determines whether or not the abnormality flag is turned off (step S404), and when the abnormality flag is turned off (step S404, Yes), the count value of the abnormality determination counter is set. It is determined whether or not an abnormality determination threshold has been exceeded (step S405).

  In step S405, if the count value of the abnormality determination counter exceeds the abnormality determination threshold value (step S405, Yes), the abnormality flag is turned on (step S406), and the process ends.

  On the other hand, if no transmission error is detected in step S402 (No in step S402), the abnormality detection unit 125d counts down the abnormality determination counter (step S407) and ends the process.

  The abnormality detection unit 125d determines that an abnormality has occurred in step S405 if the transmission stop flag is not turned off in step S401 (step S401, No), or if the abnormality flag is not turned on in step S404 (step S404, No). Even when the count value has not finished the abnormality determination threshold value (step S405, No), the process is terminated.

  Further, another example of the processing procedure of the abnormality determination process will be described with reference to FIG. FIG. 21 is a flowchart (part 2) illustrating the processing procedure of the abnormality determination processing. FIG. 21 differs from FIG. 20 in that it is determined whether or not data has been normally transmitted when the abnormality determination counter is counted down. Here, steps S501 to S506 in FIG. 21 are the same as steps S401 to S406 in FIG.

  As illustrated in FIG. 21, when no transmission error is detected in step S502 (No in step S502), the abnormality detection unit 125d determines whether normal transmission of data has been detected (step S507), and is normal. If transmission is detected (step S507, Yes), the abnormality determination counter is counted down (step S508), and the process ends. In step S507, the abnormality detection unit 125d ends the process as it is when it does not detect normal transmission of data (No in step S507).

  As described above, in the third embodiment, when the retransmission control unit 125c determines that the number of transmission errors detected or the duration of the transmission error detected within one period exceeds the transmission stop determination threshold, Transmission processing is prohibited, and the abnormality detection unit 125d detects the number of detected transmission errors or durations in a plurality of communication periods, excluding the period during which transmission processing is prohibited by the retransmission control unit 125c, and detects the detected When the number of times or duration exceeds an abnormality determination threshold that is higher than the transmission stop determination threshold, it is determined that a communication abnormality has occurred. Therefore, it is possible to accurately determine a communication abnormality.

  The embodiments of the communication system according to the present invention have been described in detail with reference to the drawings. However, these are merely examples, and various modifications and improvements are made based on the knowledge of those skilled in the art. It is possible to implement the present invention.

  For example, in each of the embodiments described above, for the purpose of improving the efficiency of data communication, the HV-ECU 1, 1 ′ transmits frame data including the start ID, and the motor ECU 2 receives frame data including the start ID. Then, the data corresponding to the start ID is transmitted. However, it is not always necessary to perform transmission / reception processing in this way. That is, the communication system according to each embodiment described above may be a communication system in which the first communication device and the second communication device transmit and receive data at a predetermined communication cycle.

  In each of the above-described embodiments, an example in which the transmission stop determination threshold is dynamically determined by the threshold determination process has been described. However, the retransmission control unit 125c is determined in advance without performing the threshold determination process. A transmission stop determination threshold may be used.

  Moreover, in each Example mentioned above, about the example when the priority of the data from HV-ECU1,1 'which is a master node is set higher than the priority of the data from motor ECU2 which is a slave node. I've explained, but it's not limited to this.

  In each of the embodiments described above, the HV-ECU 1, 1 ′ and the motor ECU 2 communicate according to the CAN protocol. However, the HV-ECU 1, 1 ′ and the motor ECU 2 perform communication arbitration similar to the CAN protocol. Communication may be performed according to another communication protocol to be performed. Here, the HV-ECU 1, 1 'and the motor ECU 2 communicate via the CAN bus, but other communication lines may be used as long as they are similar to the CAN bus.

  As described above, the communication device and the communication system according to the present invention are effective when it is desired to prevent data to be received in a predetermined communication cycle even when a transmission error occurs. It can be applied to an in-vehicle network that interconnects ECUs.

1,1 ′ HV-ECU (first communication device)
11 CAN transceiver 12 Microcomputer 121 Communication unit 121a Transmission register 121b Reception register 122 Transmission buffer 123 Reception buffer 124 Platform 125 Control unit 126 Register 125a Data storage processing unit 125b Reception completion processing unit 125c Retransmission control unit 125d Abnormality detection unit 2 Motor ECU 2 communication device)
21 CAN transceiver 22 microcomputer 221 communication unit 222 transmission buffer 223 reception buffer 224 platform 225 control unit 225a ID reading unit 225b data storage processing unit 3 motor

Claims (9)

A communication device in a communication system in which a plurality of communication devices transmit and receive data at a predetermined communication cycle,
Communication in the communication system is performed by a communication method that cannot simultaneously transmit from a plurality of devices,
A retransmission means for performing a retransmission process of the data when a transmission error of the data is detected;
When the number of transmission errors detected or the duration of a transmission error detected within one cycle in the communication cycle exceeds a first threshold, the retransmission processing in the communication cycle is prohibited and the communication cycle ends and the next And a retransmission control means for canceling the prohibition of the retransmission processing when the communication cycle starts.   2. The control device according to claim 1, wherein the control device needs to receive a predetermined amount of data within one cycle of the communication cycle as data used for a predetermined calculation process performed in a predetermined control cycle. Communication equipment.   3. The communication device according to claim 1, wherein, when transmission processing of a plurality of communication devices occurs simultaneously, the transmission processing is given priority over other communication devices. An abnormality detection means for determining that a communication abnormality has occurred when the number of transmission errors detected or the duration exceeds a second threshold that is higher than the first threshold;
When an abnormality is detected by the abnormality detection means, an abnormality control means for prohibiting transmission processing is provided,
The abnormal time control means,
The prohibition of the transmission process is not canceled even if the communication cycle in which the abnormality is detected and the transmission process is prohibited ends and the next communication cycle is started. Communication device. The abnormal time control means,
The communication apparatus according to claim 4, wherein the prohibition of transmission processing is canceled when the power is turned on or off at least. The retransmission control means includes
When the data transmission error is detected, the first time based on the time required to receive all the remaining data that needs to be received in the predetermined communication cycle and the remaining time of the predetermined communication cycle. The communication apparatus according to claim 1, wherein a threshold value is determined.   When reception of data that needs to be received in the predetermined communication cycle is not completed, data received in a communication cycle prior to the predetermined communication cycle is treated as data received in the predetermined communication cycle The communication device according to claim 1, wherein the communication device is a device.   Control means for collectively storing in the transmission buffer all data that needs to be transmitted within the predetermined communication cycle when the data stored in the reception buffer is data indicating the start of the communication cycle. The communication apparatus according to claim 1, further comprising: A communication system in which a first communication device and a second communication device transmit and receive data at a predetermined communication cycle,
The communication between the first communication device and the second communication device is performed by a communication method in which transmission from both devices cannot be performed simultaneously,
The first communication device is:
A retransmission means for performing a retransmission process of the data when a transmission error of the data is detected;
When the number of transmission errors detected or the duration of a transmission error detected within one cycle in the communication cycle exceeds a first threshold, the retransmission processing in the communication cycle is prohibited and the communication cycle ends and the next A re-transmission control means for canceling the prohibition of the re-transmission processing when the communication cycle starts.

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