JP2019213163A - Communication control unit - Google Patents

Abstract

To provide a communication control unit capable of reducing such a situation that transfer processing of a message between communication buses cannot be completed in a permissible delay time.SOLUTION: A communication control unit 100 performs transfer processing of a message between multiple communication buses. The communication control unit 100 comprises a control section 60, and a storage section 50 storing parameters for calculating a transfer processing completion time, and an allowable delayed time, i.e., a delayed time allowable as the transfer processing completion time, in association with a data ID of the message. Upon receiving the message, the control section 60 sets the transfer data generation order of the message lastly, reads the parameters, calculates the transfer processing completion time of the received message, and when the calculated transfer processing completion time exceeds the allowable delayed time, replaces the transfer data generation order of the received message with the transfer data generation order of a message in the transfer data generation order before by one.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a communication control apparatus.

  In recent years, development of automobiles having a large amount of communication information in in-vehicle communication such as connected cars and autonomous driving cars has been progressing. Currently, CAN (Controller Area Network) communication is mainly used for in-vehicle communication. For example, Patent Document 1 discloses an invention that equalizes transmission data transmission opportunities by controlling transmission priority in CAN communication.

  As the amount of communication information in in-vehicle communication increases, the load on the communication bus increases. On the other hand, providing a plurality of communication buses is considered to cope with an increase in the amount of communication information.

  When a plurality of communication buses are provided, messages are transmitted and received between the communication buses by a communication control device that controls message transfer processing between the communication buses. Here, the “message” is a group of data transmitted and received in in-vehicle communication such as CAN communication. A “message” is also called a “frame”.

JP 2001-119416 A

  In the message transfer process between communication buses, if the order of generating transfer data for transfer processing is determined based only on the priority determined according to the data content, the transfer process of low priority messages is allowed. A situation that cannot be completed within the delay time may occur.

  An object of the present invention made in view of such a viewpoint is to provide a communication control apparatus capable of reducing a situation in which a message transfer process between communication buses cannot be completed within an allowable delay time.

In order to solve the above problem, a communication control apparatus according to a first aspect
A communication control device that is connected between a plurality of communication buses and performs message transfer processing between the communication buses,
Upon receipt of the message, a control unit that generates transfer data suitable for the communication bus of the transfer destination based on the set transfer data generation order;
A parameter for calculating a transfer process completion time which is a time until the transfer process of the message is completed and an allowable delay time which is an allowable delay time as the transfer process completion time are set in the data ID of the message. A storage unit for linking and storing,
The controller is
When the message is received, the transfer data generation order of the message is set last,
Read the parameter, calculate the transfer processing completion time of the received message,
When the calculated transfer processing completion time exceeds the allowable delay time, the transfer data generation order of the received message is replaced with the transfer data generation order of the message having the previous transfer data generation order.

  According to the communication control device according to the first aspect, it is possible to reduce the situation in which the message transfer process between the communication buses cannot be completed within the allowable delay time.

It is a figure which shows a mode that the communication control apparatus which concerns on one Embodiment is connected between several communication buses. It is a block diagram which shows the structural example of the communication control apparatus which concerns on one Embodiment. It is a figure which shows an example of the table which a memory | storage part stores. It is a figure for demonstrating operation | movement of a time counter. It is a flowchart which shows an example of operation | movement of the communication control apparatus which concerns on one Embodiment. It is a figure for demonstrating step S103 of the flowchart of FIG. It is a figure for demonstrating step S104 and S105 of the flowchart of FIG. It is a figure for demonstrating step S106 of the flowchart of FIG. It is a figure for demonstrating step S104 and S105 of the flowchart of FIG. It is a figure for demonstrating step S106 of the flowchart of FIG. It is a figure for demonstrating step S104 and S105 of the flowchart of FIG. It is a figure for demonstrating step S113 of the flowchart of FIG.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

  As shown in FIG. 1, the communication control device 100 is connected between a plurality of communication buses 1 to 3. In the example illustrated in FIG. 1, the communication protocols of the communication bus 1, the communication bus 2, and the communication bus 3 are CAN, CAN FD (CAN with Flexible Data rate), and Ethernet (registered trademark) (Ethernet), respectively. CAN FD and Ethernet are communication protocols having a higher communication speed than CAN.

  Note that the communication protocols of the communication bus 1, the communication bus 2, and the communication bus 3 are CAN, CAN FD, and Ethernet, respectively, and the communication protocols of the communication buses 1 to 3 are not limited thereto.

  Moreover, in this embodiment, although the case where the communication control apparatus 100 is connected between the three communication buses 1-3 is described as an example, the number of communication buses to which the communication control apparatus 100 is connected is It is not limited to this. The number of communication buses to which the communication control device 100 is connected may be two, or four or more.

  An electronic control unit (ECU) 201 is connected to the communication bus 1. An electronic control unit 202 is connected to the communication bus 2. An electronic control unit 203 is connected to the communication bus 3. The electronic control units 201 to 203 are control units that control electrical components mounted on a vehicle such as an automobile.

  Although two electronic control units 201 are connected to the communication bus 1 in FIG. 1, the number of electronic control units 201 connected to the communication bus 1 is not limited to this. One or three or more electronic control units 201 may be connected to the communication bus 1. The same applies to the number of electronic control units 202 connected to the communication bus 2 and the number of electronic control units 203 connected to the communication bus 3.

  The communication control apparatus 100 may be mounted on a vehicle such as an automobile. The communication control apparatus 100 performs a message transfer process between the communication buses 1 to 3.

  As illustrated in FIG. 2, the communication control apparatus 100 according to the embodiment includes reception units 10-1 to 10-3, reception buffers 20-1 to 20-3, transmission buffers 30-1 to 30-3, and , Transmission units 40-1 to 40-3, a storage unit 50, a control unit 60, and a time counter 70.

  The receiving units 10-1 to 10-3 are connected to the communication buses 1 to 3, respectively.

  When receiving a message from the electronic control unit 201 shown in FIG. 1 via the communication bus 1, the receiving unit 10-1 performs processing according to the communication protocol of the communication bus 1 and stores the message in the reception buffer 20-1. To do. The process according to the communication protocol is, for example, a CRC check of the received message.

  Since the functions of the receiving units 10-2 and 10-3 are the same as the functions of the receiving unit 10-1, description of the receiving units 10-2 and 10-3 is omitted. Hereinafter, the receiving units 10-1 to 10-3 may be collectively referred to as the receiving unit 10 when it is not necessary to distinguish between them.

  The reception buffers 20-1 to 20-3 are connected to the reception units 10-1 to 10-3, respectively.

  When receiving a message from the reception unit 10-1, the reception buffer 20-1 stores the message. In addition, the reception buffer 20-1 outputs the message received from the reception unit 10-1 to the transfer data generation unit 66 of the control unit 60.

  Since the functions of the reception buffers 20-2 and 20-3 are the same as the functions of the reception buffer 20-1, the description of the reception buffers 20-2 and 20-3 is omitted. Hereinafter, the reception buffers 20-1 to 20-3 may be collectively referred to as the reception buffer 20 when it is not necessary to distinguish them.

  The transmission buffers 30-1 to 30-3 are connected to the transmission units 40-1 to 40-3, respectively.

  When receiving the transfer data from the transfer data generation unit 66, the transmission buffer 30-1 stores the transfer data. The transmission buffer 30-1 outputs the transfer data received from the transfer data generation unit 66 to the transmission unit 40-1. Here, “transfer data” is data processed by the transfer data generation unit 66 so as to conform to the communication protocol of the transfer destination. The transmission buffer 30-1 receives data processed so as to conform to the communication protocol of the communication bus 1 from the transfer data generation unit 66.

  Since the functions of the transmission buffers 30-2 and 30-3 are the same as the functions of the transmission buffer 30-1, the description of the transmission buffers 30-2 and 30-3 is omitted. Hereinafter, the transmission buffers 30-1 to 30-3 may be collectively referred to as the transmission buffer 30 when it is not necessary to distinguish between them.

  The transmission units 40-1 to 40-3 are connected to the communication buses 1 to 3, respectively.

  When receiving the transfer data from the transmission buffer 30-1, the transmission unit 40-1 performs transmission control according to the communication protocol of the communication bus 1, and transmits the transfer data to the electronic control shown in FIG. Transmit to unit 201. The transmission control according to the communication protocol is, for example, checking the state of the communication bus 1.

  Since the functions of the transmission units 40-2 and 40-3 are the same as the function of the transmission unit 40-1, the description of the transmission units 40-2 and 40-3 is omitted. Hereinafter, the transmitting units 40-1 to 40-3 may be collectively referred to as the transmitting unit 40 when it is not necessary to distinguish between them.

  The storage unit 50 is connected to the control unit 60 and stores information acquired from the control unit 60. The storage unit 50 may function as a working memory for the control unit 60. The storage unit 50 may store a program executed by the control unit 60. The storage unit 50 is configured by, for example, a semiconductor memory, but is not limited thereto, and may be configured by a magnetic storage medium or may be configured by another storage medium. The storage unit 50 may be included in the control unit 60 as a part of the control unit 60.

  The storage unit 50 stores a table in which a transfer destination port, an allowable delay time, and various parameters are associated with the data ID included in the message. FIG. 3 shows an example of a table stored in the storage unit 50.

  In the example illustrated in FIG. 3, the storage unit 50 includes “transfer ID port”, “allowable delay time”, “transfer data generation time”, “transfer speed”, “header”, and “data ID”. A table in which “the total number of bits of the footer” is linked is stored.

  The data ID is an ID included in each message and indicates what kind of data the message contains. The data ID indicates that the data included in the message is the vehicle speed, for example.

  The transfer destination port indicates which communication bus the message transfer destination is. For example, when the transfer destination port is 1ch, the message transfer destination is the communication bus 1.

  The allowable delay time is an allowable delay time as a message transfer processing completion time by the communication control apparatus 100. Here, the “transfer processing completion time” is the time from when the communication control apparatus 100 receives a message until the message transfer processing is completed.

  The transfer data generation time is a time required for the transfer data generation unit 66 to generate transfer data. As the transfer data generation time, for example, a value measured in advance may be stored in the storage unit 50.

  The transfer rate is a rate at which data can be transmitted when the transmission unit 40 transmits a message to the communication bus.

  The total number of bits of the header and footer is the total number of bits of the header included in the message and the number of bits of the footer included in the message.

  The control unit 60 controls each component of the communication control device 100. The control unit 60 may be configured by a processor such as a CPU (Central Processing Unit) that executes a program that defines a control procedure, for example. For example, the control unit 60 reads a program stored in the storage unit 50 and executes various programs.

  The control unit 60 includes a frame information extraction unit 61, a scheduling unit 62, and a transfer data generation unit 66. The processing executed by the frame information extraction unit 61, the scheduling unit 62, and the transfer data generation unit 66 is executed by a processor that constitutes the control unit 60. In addition, the processor which comprises the control part 60 does not need to be comprised with a single processor, and may be comprised with several processors.

  The frame information extraction unit 61 extracts the message data ID and the message data size from the message stored in the reception buffer 20 as frame information, and outputs the message information to the scheduling unit 62.

  The scheduling unit 62 schedules the order in which transfer data suitable for the transfer destination communication bus is generated from the message received by the receiving unit 10. Hereinafter, the order in which transfer data is generated is also referred to as “transfer data generation order”.

  The scheduling unit 62 includes a scheduler 63, a calculation unit 64, and a determination unit 65.

  When the transfer data generation unit 66 receives a message from the reception buffer 20, the scheduler 63 sets the transfer data generation order of the received message last.

  When the scheduler 63 receives an instruction to change the transfer data generation order from the determination unit 65, the scheduler 63 changes the transfer data generation order based on the received instruction.

  The scheduler 63 stores the current transfer data generation order.

  The calculation unit 64 reads “transfer data generation time”, “transfer rate”, and “total number of bits of header and footer” from the table stored in the storage unit 50, and receives the message received by the reception buffer 20. The transfer processing completion time is calculated. An example of a specific method for calculating the transfer processing completion time by the calculation unit 64 will be described later in the description of the flowchart shown in FIG.

  The determination unit 65 compares the transfer processing completion time calculated by the calculation unit 64 with respect to the message received by the transfer data generation unit 66 and the allowable delay time of the message, and the transfer processing completion time exceeds the allowable delay time. Judge whether it is. At this time, the determination unit 65 may acquire the allowable delay time of the message received by the transfer data generation unit 66 by reading the allowable delay time associated with the data ID of the message from the storage unit 50. .

  When the determination unit 65 determines that the message transfer processing completion time exceeds the allowable delay time, the transfer data generation order of the message is replaced with the transfer data generation order of the message whose transfer data generation order is the previous one. The scheduler 63 is instructed as follows.

  The transfer data generation unit 66 receives a message from the reception buffer 20. The transfer data generation unit 66 generates transfer data based on the transfer data generation order stored in the scheduler 63.

  When the transfer data is generated, the transfer data generation unit 66 refers to the table stored in the storage unit 50 and stores the generated transfer data in the transmission buffer 30 corresponding to the transfer data transfer destination port.

  When the transfer data generation unit 66 receives a new message from the reception buffer 20, the transfer data generation unit 66 interrupts the transfer data generation process.

  The time counter 70 counts an elapsed time after the transfer data generation unit 66 starts processing to generate message transfer data. Hereinafter, the process in which the transfer data generation unit 66 generates the transfer data is also referred to as “transfer data generation process”.

  The operation of the time counter 70 will be described with reference to FIG. In FIG. 4, it is assumed that the transfer data generation unit 66 starts transfer data generation processing for the received message at time t0.

  The transfer data generation unit 66 completes the transfer data generation process started at time t0 at time t2, and stores the generated transfer data in the transmission buffer 30. A time a shown in FIG. 4 represents a time obtained by subtracting the time t0 from the time t2. That is, the time a indicates the time from when the transfer data generation unit 66 starts the transfer data generation process to when the generated transfer data is stored in the transmission buffer 30.

  The transmission buffer 30 starts receiving transfer data from the transfer data generation unit 66 at time t <b> 2 and outputs the received transfer data to the transmission unit 40. The transmission unit 40 transmits the transfer data received from the transmission buffer 30 to the communication bus to which the transmission unit 40 is connected. The transmission unit 40 completes the transfer data transmission process at time t3. A time b shown in FIG. 4 represents a time obtained by subtracting the time t2 from the time t3. That is, the time b indicates the time from when the transmission buffer 30 receives the transfer data from the transfer data generation unit 66 to when the transmission unit 40 completes the transfer data transmission process.

  The time counter 70 counts the time T shown in FIG. In FIG. 4, time t1 means that the transfer data generation process by the transfer data generation unit 66 is currently proceeding to time t1. That is, the time counter 70 counts the time T from when the transfer data generation unit 66 starts the transfer data generation process to the part where the transfer data generation process is currently progressing.

  For each message received by the transfer data generation unit 66 from the reception buffer 20, the time counter 70 counts the elapsed time since the transfer data generation unit 66 started the message transfer data generation process.

  When the transfer data generation unit 66 receives a new message from the reception buffer 20, the time counter 70 receives an elapsed time count stop instruction from the control unit 60. When receiving the count stop instruction, the time counter 70 stores the count value of the message that is currently generating the transfer data, and stops counting the elapsed time.

  When the time counter 70 receives an instruction to restart counting the elapsed time from the control unit 60, the time counter 70 restarts counting the elapsed time from the stored count value.

  When the transfer data generation unit 66 completes the transfer data generation process for the message for which transfer data is currently generated, the time counter 70 receives an instruction from the transfer data generation unit 66 and clears the count value.

  With reference to the flowchart shown in FIG. 5, an example of operation | movement of the communication control apparatus 100 which concerns on one Embodiment is demonstrated. The description of the flowchart shown in FIG. 5 will be made with reference to FIGS. 6 to 12 as appropriate.

  In the description of the flowchart illustrated in FIG. 5, a case where the transfer data generation unit 66 receives a new message from the reception buffer 20 while receiving two messages from the reception buffer 20 will be described as an example.

  The control unit 60 of the communication control apparatus 100 constantly monitors whether the reception buffer 20 has received a new message (step S101).

  When the reception buffer 20 has not received a new message (No in step S101), the control unit 60 repeats the process in step S101.

  When the reception buffer 20 receives a new message (Yes in step S101), the frame information extraction unit 61 extracts frame information from the message stored in the reception buffer 20 (step S102). Hereinafter, a newly received message will be referred to as a “received message”. The frame information extraction unit 61 extracts the data ID of the received message and the data size of the received message as frame information, and outputs the extracted data to the scheduling unit 62. In addition, the reception buffer 20 outputs the received message to the transfer data generation unit 66.

  The scheduler 63 sets the transfer data generation order of the received message last (step S103). In this description, since two messages are being processed in the transfer data generation unit 66, the scheduler 63 sets the transfer data generation order of the received message to the third. This is shown in FIG. It is assumed that the two messages already being processed in the transfer data generation unit 66 are “message 1” and “message 2”.

  The calculation unit 64 calculates the transfer message completion time of the received message (step S104). With reference to FIG. 7, calculation of the reception message transfer process completion time by the calculation unit 64 will be described.

In FIG. 7, it is assumed that the reception unit 10 receives a reception message at time t1, and the transmission unit 40 completes transmission of transfer data generated from the reception message at time t2. In this case, the transfer processing completion time is a time represented as c _RX in FIG.

The calculation unit 64 calculates the transfer processing completion time c _RX of the received message using the following formula (1).
c _RX = (a ₁ −T ₁ ) + (a ₂ −T ₂ ) + a _RX + b _RX (1)
Here, a ₁ is the transfer data generation time of message 1. a ₂ is the transfer data generation time of message 2. a _RX is the transfer data generation time of the received message. The calculation unit 64 reads the transfer data generation time associated with the data ID of each message with reference to a table stored in the storage unit 50 as shown in FIG.

In Expression (1), T ₁ is a count value stored in the time counter 70 for the message 1. That is, T ₁ means that the transfer data generation process of message 1 has advanced by T ₁ . T ₂ is a count value stored in the time counter 70 for the message 2. In the example shown in FIG. 7, T ₂ is zero. The calculation unit 64 reads T ₁ and T ₂ from the time counter 70.

In the equation (1), b _RX is a time taken when the transmission data generated by the transfer data generation unit 66 from the received message is transmitted by the transmission unit 40. Hereinafter, the time taken for the transfer data to be transmitted by the transmission unit 40 will be referred to as “transfer data transmission time”.

The calculation unit 64 calculates the transfer data transmission time b _RX by the following formula (2).
b _RX = (number of bits of the entire transfer data) / (transfer speed of the destination communication bus) (2)
Here, the calculation unit 64 calculates the “number of bits of the entire transfer data” in Expression (2) by reading the data size of the received message extracted by the frame information extraction unit 61 and the “header” read from the table stored in the storage unit 50. And the total number of bits of the footer ”are added together. In addition, the calculation unit 64 reads “transfer speed of the transfer destination communication bus” in Expression (2) with reference to “transfer speed” of the table stored in the storage unit 50.

The transfer data transmission process by the transmission unit 40 can be executed independently of the transfer data generation process by the transfer data generation unit 66. For this reason, b ₁ and b ₂ shown in FIG. 7 are not added in the calculation of c _RX according to Equation (1).

The determination unit 65 determines whether the received message transfer processing completion time c _RX calculated by the calculation unit 64 exceeds the allowable delay time of the received message (step S105). The determination unit 65 reads the allowable delay time of the received message from the table stored in the storage unit 50. In FIG. 7, the allowable delay time of the received message is shown as W _RX . In the example shown in FIG. 7, the transfer message completion processing time c _RX of the received message exceeds the allowable delay time W _RX of the received message. In FIG. 7, the allowable delay times of message 1 and message 2 are shown as W ₁ and W ₂ , respectively. In the example shown in FIG. 7, the transmission of the transfer data of message 1 is completed without exceeding W ₁ . The transmission of the transfer data of message 2 is completed without exceeding W ₂ .

When the determination unit 65 determines that the received message transfer processing completion time c _RX calculated by the calculation unit 64 exceeds the allowable delay time of the received message (Yes in step S105), the scheduler 63 transfers the received message. The data generation order is exchanged with the transfer data generation order of message 2, which is the previous message in the transfer data generation order (step S106). This is shown in FIG. As illustrated in FIG. 8, the scheduler 63 sets the transfer data generation order of the received message to the second and the transfer data generation order of the message 2 to the third.

  FIG. 9 shows a state when the transfer data generation order of the received message and the message 2 is switched and the transfer data generation order of the received message is set to the second. In this state, the calculation unit 64 executes step S104 again to calculate the received message transfer processing completion time.

The calculating unit 64 calculates the transfer processing completion time c _RX of the received message when the transfer data generation order of the received message is second, using the following formula (3).
c _RX = (a ₁ −T ₁ ) + a _RX + b _RX (3)

The determination unit 65 determines whether or not the transfer processing completion time c _RX of the received message calculated by the calculation unit 64 using Equation (3) exceeds the allowable delay time of the received message (step S105). In the example shown in FIG. 9, the received message transfer processing completion time c _RX calculated by the equation (3) still exceeds the allowable delay time W _RX of the received message.

  Accordingly, the determination unit 65 proceeds to step S106 again, and the scheduler 63 replaces the transfer data generation order of the received message with the transfer data generation order of the message 1 that is the previous message in the transfer data generation order. This is shown in FIG. As illustrated in FIG. 10, the scheduler 63 sets the transfer data generation order of the received message to the first and the transfer data generation order of the message 1 to the second.

  FIG. 11 shows a state in which the transfer data generation order of the received message and the message 1 is switched and the transfer data generation order of the received message is set to the first. In this state, the calculation unit 64 executes step S104 again to calculate the received message transfer processing completion time.

The calculating unit 64 calculates the transfer processing completion time c _RX of the received message when the transfer data generation order of the received message is the first, using the following formula (4).
c _RX = a _RX + b _RX (4)

The determination unit 65 determines whether or not the transfer processing completion time c _RX of the received message calculated by the calculation unit 64 using Equation (4) exceeds the allowable delay time of the received message (step S105). In the example shown in FIG. 11, the reception message transfer processing completion time c _RX calculated by the equation (4) does not exceed the allowable delay time W _RX of the reception message. Therefore, the determination in step S105 is No, and the determination unit 65 proceeds to step S107.

  The transfer data generation unit 66 reads the count value of the received message from the time counter 70, and starts the transfer data generation process using the read count value as the restart position (step S107). Since the transfer data generation processing has not been executed for the received message so far, the count value by the time counter 70 is zero. Therefore, the transfer data generation unit 66 starts the transfer data generation process from the first part of the received message. When the transfer data generation process starts, the transfer data generation unit 66 transmits a count start trigger to the time counter 70 so as to start counting the elapsed time. When the transfer data is generated, the transfer data generation unit 66 reads the transfer destination port from the table stored in the storage unit 50 and stores the generated transfer data in the corresponding transmission buffer 30.

  The control unit 60 monitors whether the reception buffer 20 has received a new message while the transfer data generation unit 66 is executing the transfer data generation process (step S108).

  When the reception buffer 20 receives a new message (Yes in step S108), the transfer data generation unit 66 interrupts the transfer data generation process. The time counter 70 stores the count value when the transfer data generation process is interrupted, and stops counting the elapsed time (step S109). After executing step S109, the control unit 60 returns to step S102.

  When the reception buffer 20 has not received a new message (No in step S108), the transfer data generation unit 66 determines whether the transfer data generation process has been completed (step S110). If the transfer data generation process has not been completed (No in step S110), the transfer data generation unit 66 repeats the process in step S110. When the transfer data generation process is completed (Yes in step S110), the transfer data generation unit 66 notifies the scheduling unit 62 that the transfer data generation process is completed. In addition, the transfer data generation unit 66 instructs the time counter 70 to clear the count value of the message for which transfer data generation processing has been completed.

  The scheduler 63 determines whether there is a message for which transfer data generation processing has not been completed (step S111).

  If there is no message for which transfer data generation processing has not been completed (No in step S111), the control unit 60 clears the transfer data generation order stored in the scheduler 63 (step S112), and returns to step S101.

  If there is a message for which transfer data generation processing has not been completed (Yes in step S111), the scheduler 63 increments the transfer data generation order of a waiting message for which transfer data generation processing has not been completed by one (step S113). . FIG. 12 shows how the transfer data generation order of message 1 and message 2 is advanced. When the scheduler 63 raises the transfer data generation order of the waiting message, the scheduler 63 notifies the transfer data generation unit 66 of the message having the first transfer data generation order. The transfer data generation unit 66 executes the process of step S107 for the message having the first transfer data generation order.

  According to the communication control apparatus 100 according to the present embodiment, when receiving a message, the control unit 60 sets the transfer data generation order of the message last. Thereafter, the control unit 60 reads the parameters from the storage unit 50 and calculates the transfer processing completion time of the received message. Then, when the calculated transfer processing completion time exceeds the allowable delay time, the control unit 60 replaces the transfer data generation order of the received message with the transfer data generation order of the previous message in the transfer data generation order. Thereby, the communication control apparatus 100 according to the present embodiment can reduce the situation in which the message transfer process between the communication buses cannot be completed within the allowable delay time. Further, in the processing of the control unit 60 of the communication control apparatus 100 according to the present embodiment, the control unit 60 does not require to be configured with a processor having a high clock frequency, and thus the cost of the processor can be reduced.

  Further, according to the communication control apparatus 100 according to the present embodiment, when the transfer data generation order is changed, the control unit 60 calculates the transfer process completion time in the transfer data generation order after the change. When the transfer processing completion time calculated in the transfer data generation order after the replacement exceeds the allowable delay time, the control unit 60 sets the transfer data generation order of the received message to the transfer data generation order one more previous. Replace with the message transfer data generation order. As a result, the communication control apparatus 100 according to the present embodiment can further reduce the situation in which the message transfer process between the communication buses cannot be completed within the allowable delay time.

  Also, according to the communication control apparatus 100 according to the present embodiment, the control unit 60 repeats the process of changing the transfer data generation order until the transfer process completion time of the received message does not exceed the allowable delay time. As a result, the communication control apparatus 100 according to the present embodiment can further reduce the situation in which the message transfer process between the communication buses cannot be completed within the allowable delay time.

  Although one embodiment according to the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various changes or modifications based on the present disclosure. Accordingly, it should be noted that these variations or modifications are included in the scope of the present disclosure. For example, the functions included in each means can be rearranged so as not to be logically contradictory, and a plurality of means can be combined into one or divided.

1, 2, 3 Communication bus 10 Reception unit 20 Reception buffer 30 Transmission buffer 40 Transmission unit 50 Storage unit 60 Control unit 61 Frame information extraction unit 62 Scheduling unit 63 Scheduler 64 Calculation unit 65 Determination unit 66 Transfer data generation unit 70 Time counter 100 Communication control device 201, 202, 203 Electronic control unit (ECU)

Claims (7)

A communication control device that is connected between a plurality of communication buses and performs message transfer processing between the communication buses,
Upon receipt of the message, a control unit that generates transfer data suitable for the communication bus of the transfer destination based on the set transfer data generation order;
A parameter for calculating a transfer process completion time that is a time until the transfer process of the message is completed and an allowable delay time that is an allowable delay time as the transfer process completion time are set in the data ID of the message. A storage unit for linking and storing,
The controller is
When the message is received, the transfer data generation order of the message is set last,
Read the parameter, calculate the transfer processing completion time of the received message,
When the calculated transfer processing completion time exceeds the allowable delay time, the communication control device replaces the transfer data generation order of the received message with the transfer data generation order of the message whose transfer data generation order is one previous. The communication control device according to claim 1,
The controller is
When the transfer data generation order is changed, the transfer process completion time is calculated in the transfer data generation order after the change,
When the transfer processing completion time calculated in the transfer data generation order after the replacement exceeds the allowable delay time, the transfer data generation order of the received message is changed to a message whose transfer data generation order is one before. The communication control device is switched with the transfer data generation order. The communication control device according to claim 2,
The communication control device, wherein the control unit repeats the process of changing the transfer data generation order until the transfer process completion time of the received message does not exceed the allowable delay time. In the communication control device according to any one of claims 1 to 3,
The control unit is configured to generate the transfer data of the message whose transfer data generation order is earlier than the received message, the time to generate the transfer data of the received message, and the time of the received message. A communication control device that calculates the transfer process completion time by adding together the time for transmitting transfer data to the transfer destination communication bus. In the communication control device according to any one of claims 1 to 4,
A communication control device, further comprising a time counter that counts an elapsed time from the start of the transfer data generation process for each received message. The communication control device according to claim 5, wherein
The control unit, upon receiving the message, interrupts the generation process of the transfer data for the message for which the transfer data is being generated,
When the transfer data generation process is interrupted, the time counter stores a value of the elapsed time and stops counting the elapsed time. The communication control device according to claim 6,
The control unit starts the transfer data generation processing from the count value of the elapsed time stored in the time counter when the transfer data generation order is changed.

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