JP5223809B2 - Synchronous communication system - Google Patents

Description

  The present invention relates to a synchronous communication system connected to a network such as a vehicle.

  As is well known, a processing device that controls various devices mounted on the vehicle according to the traveling state of the vehicle is provided for each vehicle, and the processing devices are connected to each other via a network. By passing information, integrated control of the vehicle through a plurality of processing devices is performed.

  By the way, for integrated control of vehicles, there are processes that a plurality of processing devices should perform in synchronization, such as simultaneous acquisition of various information at a specific time. In the case of time management, the accuracy of the synchronization cannot be maintained high due to a time lag between the timers caused by individual differences of each timer.

  Under such circumstances, various techniques have been proposed for maintaining the synchronization of processes executed in a plurality of processing apparatuses connected to a network with high accuracy using the network connection. An example has been proposed. The synchronous communication system described in Patent Document 1 is a system used between, for example, PHS base stations, and synchronizes a local timer provided in each base station between the base stations, thereby allowing the base stations to synchronize with each other. The execution timing of the process managed by the local timer is synchronized every time. That is, when wireless communication is performed between base stations, a predetermined slot of a plurality of slots used for the communication is changed from the local timer of the communication destination base station to the local timer of the communication source base station. It is used to synchronize, and the synchronization of the local timers of these base stations is maintained.

Japanese Patent Laid-Open No. 2007-6196

  However, in the synchronous communication system described in Patent Document 1, since the base stations other than the communicating base station are not synchronized unless communication is performed, the synchronization of the local timer between the communicating base stations is maintained. Even if it is done, there is a possibility that the local timer is out of synchronization in the base station that is not communicating at that time.

  In recent years, when time division multiplex communication is performed in network communication, each processing device connected to the network detects a time (network time) unique to the network based on a time division time interval or the like, and the network A method for synchronizing processing between processing devices based on time has also been proposed. This network time can be detected with high accuracy by each processing device connected to the network based on communication information, so that the processing of these devices is performed with high synchronization. However, even in this case, for example, if there is a problem such as a temporary disconnection of the network, the synchronization may be impaired such that the network time cannot be detected accurately.

The present invention has been made in view of such circumstances, and its purpose is to perform processing with high tolerance even when synchronous communication is performed based on a timing commonly detected between devices connected to a network. It is an object of the present invention to provide a synchronous communication system that can maintain the synchronicity.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
In order to solve the above-mentioned problem, the invention described in claim 1 is detected while detecting a periodic timing based on communication information transmitted from each of a plurality of processing devices connected to the network via the network. This is a synchronous communication system that maintains the synchronization with the processing executed in synchronization with the timing by another processing device connected to the network by executing the processing so as to synchronize with the timing. Each of the processing devices is reset each time the periodic timing is detected, and a trigger that causes the processing device to start executing a process based on the passage of a preset time after the reset. A general-purpose timer that generates a period of time that is longer than the period of one cycle of the periodic timing. Ri Na is constant, each of said processing apparatus, when it is expected that inconvenience to the network occurs, stops the detection of the periodic timing and summarized in that for generating a trigger to the general-purpose timer.

According to such a configuration, the processing executed by each processing device can be synchronized with the processing of other devices at a periodic timing detected based on the communication information of the network, and the network When inconvenience is expected to occur, the processing is executed by the trigger of the general-purpose timer. As a result, in a normal time, processing having high synchronization with processing of other devices connected to the network is performed at a periodic timing detected from the network, and an abnormality in which the timing is not detected occurs. When this is expected , the process is executed while maintaining the synchronization by the trigger of the general-purpose timer. Thus, in the case a temporary non convenient for network communications is so that occur, as the synchronization of the process executed in the synchronous communication system is maintained, the reliability of the processing in the synchronous communication system is maintained Become.

  According to a second aspect of the present invention, the general-purpose timer has a time longer than a time obtained by adding a time of one period of the periodic timing and an error time allowed for the detection of the timing as the timer time. Is set as the gist.

According to such a configuration, when the time of one cycle of the periodic timing exceeds an error allowed for the detection, the processing of the processing device is executed by the trigger generated by the general-purpose timer. . Thus, if more periodic timing in non capital if the network as detected such Kunar, if as short as possible a timer time, in a short period of time from the time the timing is not detected A trigger is generated, and instead of the timing, the trigger maintains synchronization of execution of processing by the processing device. As a result, even when the periodic timing is not detected, the reliability of the processing that requires the synchronization in the synchronous communication system is maintained.

  According to a third aspect of the present invention, the general-purpose timer is reset even when the trigger is generated by itself, and the timer time set as the timer time is set only when the general-purpose timer is reset by the trigger. The gist is that the time equal to the time of one cycle of the periodic timing is set.

According to such a configuration, the trigger non capital case of network A more periodic if the timing is such that a constant time period detected such Kunar, every time the general-purpose timer is equal to one period of the periodic timing And the processing by the processing device is executed. As a result, even when periodic timing is not detected over a relatively long period, the synchronization of the processing executed by the processing device is maintained, and the reliability of the processing that requires synchronization in the synchronous communication system is ensured. Will be maintained.

  According to a fourth aspect of the present invention, time division multiplexing communication information is transmitted to the network, and each of the processing devices includes communication information transmitted by the time division multiplexing method. The gist is that a network timer that measures network time common to the network based on the divided time intervals and obtains the periodic timing based on the network time is provided.

  According to the time division multiplexing communication information, each processing apparatus connected to the network can measure the network time common to the network based on the time interval of the time division communication information.

Therefore, according to such a configuration, the processing of each processing device is executed at a periodic timing acquired from the network time common to the network, so that the processing performed by each processing device is high. Synchronization will be maintained. Thus, when the communication information is time-division multiplexing, synchronous communication system is configured to maintain synchronization of the execution of the process during normal, periodic timing inconvenient for network communications is occurred when the detected such Kunar Anyway, the synchronization of execution of the process is maintained.

  The gist of the invention according to claim 5 is that the length of the unit time of the general-purpose timer is adjusted for each corresponding processing device based on the network time acquired by the network timer.

  According to such a configuration, an error generated between the time measured by the general-purpose timer whose unit time length is adjusted and the time length measured by the network time is kept small. As a result, even when a trigger is generated by a general-purpose timer, the synchronization between the periodic timing and the generated trigger is kept high, and the synchronization of processing executed by the processing device is kept high. Become so.

According to a sixth aspect of the present invention, the network is an in-vehicle network mounted on a vehicle on which a navigation system is mounted, and a travel section in which the network is likely to be affected by a disturbance is a disturbance section information. Each of the processing devices is inconvenienced in the network during the period when the navigation system detects that the vehicle is traveling in the traveling section registered in the disturbance section information. The gist is that the detection of the periodic timing is temporarily stopped in anticipation, and the execution of the processing is continued based on generation of a trigger by the general-purpose timer.

  According to such a configuration, when it is detected that the vehicle is traveling in a disturbance section that is affected by disturbance in network communication, the processing of each processing device is executed by the trigger of each general-purpose timer. To do. As a result, when a decrease in the synchronization of the processing executed by each processing device is predicted in advance, a decrease in the synchronization of the execution of the process due to the undetected periodic timing or the erroneous detection caused by a disturbance is caused. While suppressing, it becomes possible to maintain the synchronization of the execution of the processing of each processing apparatus.

The block diagram which shows the schematic structure about one Embodiment of the synchronous communication system which concerns on this invention. 6 is an exemplary flowchart illustrating processing when an interrupt signal is input to the arithmetic device according to the embodiment. 6 is an exemplary flowchart illustrating processing when an interrupt signal (periodic timing) based on a network timer is generated in the processing apparatus of the embodiment. 6 is an exemplary flowchart illustrating processing when an interrupt signal based on a trigger of a general-purpose timer is generated in the processing apparatus of the embodiment. The timing chart shown about the timing of the process performed with the processing apparatus of the embodiment. The block diagram which shows the schematic structure about other embodiment about the processing apparatus of the synchronous communication system which concerns on this invention. The block diagram which shows the schematic structure about other embodiment of the synchronous communication system which concerns on this invention.

  Hereinafter, an embodiment of a synchronous communication system according to the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram showing a functional configuration of a synchronous communication system mounted on a vehicle.

  As shown in FIG. 1, the vehicle synchronous communication system includes a network 10 mounted on the vehicle and a plurality of electronic processing units (ECUs) 11, 12, 13 connected to the network 10. ing. The network 10 enables transmission of communication information between the ECUs 11, 12, and 13 connected thereto, and in the present embodiment, the communication information is transmitted by a time division multiplexing method. It is like that. Each of the ECUs 11, 12, and 13 is a device that controls a control object associated therewith, and a control program corresponding to the control object is executed there. In the present embodiment, these control programs are synchronous applications that require high synchronicity for execution in order to perform integrated control of the vehicle, and the ECUs 11, 12, and 13 are highly synchronized with each other. It is executed while maintaining sex.

  Next, each ECU 11, 12, 13 including the configuration for maintaining such synchronism will be described. Since the ECUs 11, 12, and 13 have the same configuration, the configuration of the ECU 11 will be mainly described in detail below. For convenience of explanation, the configurations of the other ECUs 12, 13 are the same. Are given the same numbers, and detailed description thereof is omitted.

  The ECU 11 temporarily stores an arithmetic unit (CPU) 21 that executes arithmetic processing of a control program, a read-only memory (ROM) that stores control programs and data necessary for the control, and CPU arithmetic results. And a storage device 22 including a volatile memory (RAM) stored in the storage device. As a result, the ECU 11 controls the control target by reading the control program and the like held in the ROM of the storage device 22 into the arithmetic device 21 and executing the control program. In addition, a plurality of interrupt signals can be input to the arithmetic device 21, and a control program is associated as a target of synchronous application processing executed based on the interrupt signals. As a result, when the interrupt signal is input, the arithmetic unit 21 causes the control program associated with the interrupt signal to be executed. Therefore, when an interrupt signal synchronized with each of the ECUs 11, 12, and 13 is input, the processing of each synchronous application is executed with synchronization.

  The ECU 11 has a general-purpose timer 23 that generates a trigger (interrupt signal) based on a set timer time, and a communication interface that enables communication through the network 10 and generates periodic timing (interrupt signal). 24 is provided.

  The general-purpose timer 23 compares the elapsed time accumulated in the timer with a preset timer time, and generates a trigger when the elapsed time is equal to or greater than the timer time. 21 and the communication interface 24. The general-purpose timer 23 accumulates the elapsed time of the timer based on a clock signal generated by an internal clock generator (not shown) provided in the ECU 11. The elapsed time of the timer is reset to “0” by being reset, and is accumulated again from “0”. The timer time can be arbitrarily set from the outside. In this embodiment, the timer time is set from the arithmetic unit 21 as necessary. When a trigger is generated from the general-purpose timer 23, the trigger is input to the arithmetic unit 21 and the communication interface 24 as one interrupt signal.

  The communication interface 24 is an interface for connecting the ECU 11 to the network 10 that transmits information by the time division multiplexing method, and is connected to the network 10, the arithmetic device 21, and the general-purpose timer 23. The communication interface 24 converts the information of the ECU 11 into time division multiplexing communication information and transmits it to the network 10, and converts the time division multiplexing communication information received from the network 10 into information recognizable by the ECU 11. As a result, the ECU 11 can transmit and receive information via the network 10 with the other ECUs 12 and 13 having the same configuration. That is, the ECU 11 can transmit the information to each of the other ECUs 12 and 13 and the information of the other ECUs 12 and 13 can be transmitted. Thereby, the synchronous communication system makes each ECU11,12,13 share vehicle information, such as a vehicle speed and an engine speed, for example.

  The communication interface 24 is provided with a network timer 241. The network timer 241 measures the network time common to the network 10 based on the time-division communication information transmitted by the time division multiplexing method. Further, the network timer 241 detects a periodic timing at a predetermined cycle (C1) determined in advance based on the measured network time. Accordingly, the communication interface 24 outputs the periodic timing detected by the network timer 241 to the arithmetic device 21 and the general-purpose timer 23, respectively. At this time, this timing is input to the arithmetic unit 21 as another interrupt signal different from the trigger of the general-purpose timer 23.

  Here, the network time of this embodiment and the time division multiplexing method for measuring it will be described. Here, for convenience of explanation, the ECU 11 is indicated as a node A, the ECU 12 is indicated as a node B, and the ECU 13 is indicated as a node C. In the time division multiplexing system of this embodiment, each node is assigned a transmission time that does not overlap in time and is repeated in the same cycle. From this, the period of time for transmission of each node is always constant, and the interval between two transmission times adjacent in time is also always constant. Specifically, the transmission times having the same period are assigned to the node A, the node B, and the node C so that the transmission times do not overlap each other. Based on these things, the network timer 241 measures network time. That is, the transmission period of each of the node A, the node B, and the node C, the time interval of the two transmission times of the node A and the node B, the node B and the node C, or the node C and the node A, etc. , And a predetermined calculation process is performed using these measurement results to measure the network time common to the network 10. Although the network time measured in this way is measured separately for each node, since it is measured based on the same communication information, each node has high synchronization.

For this reason, in the synchronous communication system, the periodic timing detected by the ECU 11 for each predetermined period (C1) with respect to the network time is similarly set to other ECUs.
12 and 13 have high synchronization with the periodic timing detected. As a result, synchronous application processing executed using such periodic timing as an interrupt signal is also executed with high synchronization. However, if inconvenience such as a temporary disconnection of the network occurs and the network time cannot be detected accurately, the synchronization of the synchronization application processing secured in this way may be impaired.

  Then, next, in this synchronous communication system, the structure which gives high tolerance to the synchronous property of a synchronous application process is demonstrated with reference to FIGS. FIG. 2 is a flowchart showing a process when an interrupt process occurs in the arithmetic device 21, and FIG. 3 is a flowchart showing a process when an interrupt occurs at a periodic timing in the ECU 11. FIG. 4 is a flowchart showing processing when an interruption due to the trigger of the general-purpose timer occurs in the ECU 11, and FIG. 5 is a timing chart showing timing of execution of processing of the synchronous application in the synchronous communication system. In the present embodiment, when the network time is normally measured, it is assumed that periodic timing based on the network time is detected at intervals of the period C1 (see FIG. 5). The period C1 is 1 ms, for example.

First, processing for an interrupt signal performed in the arithmetic unit 21 will be described.
When an interrupt signal based on either the periodic timing or the trigger of the general-purpose timer 23 is input to the arithmetic device 21, an interrupt process based on the interrupt signal is generated in the arithmetic device 21, and as shown in FIG. Processing is executed (step S1 in FIG. 2). In the synchronous application process, the process of the control program is executed based on the interrupt signal in synchronization with the interrupt signal. When the synchronous application process is performed, the arithmetic unit 21 determines whether or not the interrupt signal is based on the periodic timing of the network timer 241 (step S2 in FIG. 2). Whether the interrupt signal is due to a periodic timing or a trigger of the general-purpose timer 23 is determined based on, for example, the difference between the interrupt signal terminals to be input. When the interrupt signal is based on the periodic timing of the network timer 241 (YES in step S2 in FIG. 2), the arithmetic unit 21 adds a backup time C2 (described later in detail) to the timer time of the general-purpose timer 23 (see FIG. 5). ) Is set (step S3 in FIG. 2), and the interrupt process is terminated. On the other hand, when the interrupt signal is not based on the periodic timing of the network timer 241 (NO in step S2 in FIG. 2), the arithmetic unit 21 determines the period C1 of one cycle of the periodic timing as the timer time of the general-purpose timer 23. Is set to a time equal to (= C1) (step S4 in FIG. 2), and the interrupt process is terminated. That is, the backup time C2 is set as the timer time of the general-purpose timer 23 when the interrupt signal has a periodic timing, and when the interrupt signal is a trigger of the general-purpose timer 23, the timer time is set to one cycle C1 of the periodic timing. An equal time (= C1) is set.

  As a result, when the periodic timing is normally detected for each period C1, an interrupt signal based on the periodic timing is input to the arithmetic unit 21 and the general-purpose timer 23.

That is, as shown in FIG. 3, when an interrupt occurs, the ECU 11 outputs an interrupt signal based on the periodic timing detected by the network timer 241 from the communication interface 24 (step S10 in FIG. 3). When the output interrupt signal is input to the arithmetic device 21 (step S11 in FIG. 3), the arithmetic device 21 executes processing based on this interrupt. That is, in this process, the synchronous application process is performed, and the arithmetic unit 21 sets the backup time C2 to the timer time of the general-purpose timer 23. This interrupt signal is also input to the general-purpose timer 23 (step S12 in FIG. 3). The general-purpose timer 23 is reset by this interrupt signal. When these processes are completed, the interrupt process based on this periodic timing is completed. In this case, the general-purpose timer 23 is reset before the elapsed time of the timer (here, the cycle C1) reaches the timer time (here, the backup time C2). The elapsed time of the timer is integrated and a backup time C2 is set as the timer time.

  On the other hand, if the periodic timing is not normally detected due to inconvenience in network communication due to temporary disconnection or the like, the general purpose timer 23 generates a trigger when the timer time (backup time C2) elapses, and the arithmetic device 21 An interrupt signal based on the trigger is input to the timer 23.

  That is, as shown in FIG. 4, when an interrupt occurs, the ECU 11 outputs an interrupt signal based on the trigger generated by the general-purpose timer 23 from the general-purpose timer 23 (step S20 in FIG. 4). When the output interrupt signal is input to the arithmetic device 21 (step S21 in FIG. 4), the arithmetic device 21 executes a process based on the interrupt process. That is, in this process, synchronous application processing is performed, and the arithmetic unit 21 sets a time (= C1) equal to the period C1 of the periodic timing as the timer time of the general-purpose timer 23. This interrupt signal is also input to the general-purpose timer 23 itself (step S22 in FIG. 4). The general-purpose timer 23 is reset by this interrupt signal. When these processes are completed, the interrupt process based on the trigger of the general-purpose timer 23 ends. In this case, the general-purpose timer 23 is reset after the elapsed time of the timer (here, the backup time C2) reaches the timer time (here, the backup time C2) and outputs a trigger, and again from “0”. The elapsed time of the timer is integrated, and a time (= C1) equal to the period C1 of the periodic timing is set as the timer time.

Further, details of the operation of the ECU 11 of such a synchronous communication system will be described as time elapses.
First, as shown in FIG. 5, when the periodic timing is normally detected from the network timer 241, the start timing PT of the synchronous application P that is executed at the timing is detected as a periodic timing. Coincides with time t1 to t3. At this time, the backup time C2 that is longer than the predetermined period C1 by the additional time α is set as the timer time of the general-purpose timer 23, and the general-purpose timer 23 is configured so that the elapsed time of the timer reaches the backup time C2. First, the timer is reset at a periodic timing, and the elapsed time of the timer is reaccumulated from the time t1 to t3. At this time, since the timer of the general-purpose timer 23 is reset at a periodic timing, the backup time C2 is set as the timer time. The additional time α is, for example, 0.05 ms, and at this time, the backup time C2 (= C1 + α) is, for example, 1.05 ms.

  Note that the additional time α is set to a time slightly longer than the error time allowed when detecting the periodic timing from the network time, and when there is a possibility that the periodic timing is not detected, immediately, That is, the trigger of the general-purpose timer 23 is generated based on the backup time C2 as quickly as possible. As a result, the synchronization application process is maintained in synchronism although it has a time lag of the additional time α. In this way, by comparing the timer time in parallel with the detection of the periodic timing, based on the occurrence of the inconvenience that the periodic timing is not detected, which has been conventionally performed, Compared to the case where the processing corresponding to the inconvenience not detected is started, the inconvenience can be quickly dealt with.

  Next, when a problem occurs in the network and the periodic timing is not normally detected from the network timer 241 at the time t4, the general-purpose timer 23 adds the additional time α to the time t4 because the timer is not reset. At time t4a, the backup time C2 is reached and a trigger is generated. The activation timing PT of the synchronous application P that is processed by this trigger coincides with the time t4a at which the trigger is generated. That is, the synchronization of the synchronization application process is maintained in a form having a time lag of the additional time α. At this time, since the timer is reset by the trigger, the general-purpose timer 23 is set to a time (= C1) equal to a predetermined cycle C1.

  After that, when the periodic timing is not detected even at time t5 and the general-purpose timer 23 is not reset, the general-purpose timer 23 reaches the predetermined period C1 and triggers at the time t5a when the additional time α is added to the time t5. Is generated. The activation timing PT of the synchronous application P that is processed by this trigger coincides with the time t5a at which the trigger is generated. That is, at this time as well, the synchronization application process maintains its synchronism in the form of a time lag of the additional time α. At this time, since the timer is reset by the trigger, the general-purpose timer 23 is set to a time (= C1) equal to a predetermined cycle C1.

  After that, when the periodic timing is normally detected at time t6, the activation timing PT of the synchronous application P that executes processing at the timing coincides with time t6 at which the periodic timing is detected. At this time, a period C3 between the time point t5a and the time point t6 is a period C3 shorter than the predetermined period C1 by the additional time α, but the shortened time is as short as an error time allowed for periodic timing detection. And shortening the time is minimized. In other words, at this time, the synchronization application process maintains synchronization with the periodic timing. This also reduces the possibility that the period C3 will be shorter than the processing time of the synchronous application P (indicated by the length of the frame surrounding P in FIG. 5), and the synchronous application P because the processing time is insufficient. The possibility that a so-called task omission will be eliminated is also reduced. At this time, the timer time of the general-purpose timer 23 is set to a time (= C1) equal to the predetermined period C1, but since the integration start is delayed by the additional time α from the periodic timing, the general-purpose timer 23, the elapsed time of the timer is reset at a periodic timing prior to reaching the predetermined period C1, and the elapsed time of the timer is re-accumulated from time t6. At this time, since the timer is reset at a periodic timing, the backup time C2 is set as the timer time.

As described above, according to the synchronous communication system of the present embodiment, the effects listed below can be obtained.
(1) The synchronous application process executed by each of the ECUs 11 to 13 is synchronized with the synchronous application process of the other ECUs 11 to 13 at a periodic timing detected based on the communication information of the network 10, and the timing is not detected. In this case, the synchronous application process is executed by the trigger of the general-purpose timer 23. Thereby, at normal time, each ECU11-13 performs the process which has high synchronism between ECU11-13 of the other apparatus connected to this network 10 by the periodic timing detected from the network 10. Can do. In addition, even when the periodic timing is not detected, the process is executed while maintaining the synchronization by the trigger of the general-purpose timer 23. As a result, even when inconvenience such as temporary disconnection occurs in network communication, the synchronization of processing executed in the synchronous communication system is maintained, and the reliability of processing in the synchronous communication system is maintained. Become.

(2) When the time of one cycle C1 of the periodic timing exceeds an error allowed for the detection, a synchronous application process of the ECU 11 (12, 13) is executed by a trigger generated by the general-purpose timer 23. I did it. As a result, if the periodic timing is not detected due to inconveniences of the network 10 and the like, if the timer time is set as short as possible, a trigger is generated within a short time from the time when the timing is not detected. Thus, instead of the timing, the trigger maintains the synchronization of the execution of the processing by the ECU 11 (12, 13). As a result, even when the periodic timing is not detected, the reliability of the processing that requires the synchronization in the synchronous communication system is maintained.

  (3) Even if the periodic timing is not detected for a certain period due to the inconvenience of the network 10, the general-purpose timer 23 generates a trigger every time equal to one period C1 of the periodic timing, and the ECU 11 (12 , 13) is executed. As a result, even when periodic timing is not detected over a relatively long period, the synchronization of the processing executed by the ECU 11 (12, 13) is maintained, and the processing in which synchronization is required in the synchronous communication system The reliability will be maintained.

  (4) According to the time-division multiplexing communication information, each ECU 11 (12, 13) connected to the network 10 determines the network time common to the network 10 based on the time interval of the time-division communication information. measure.

  Therefore, according to such a configuration, each ECU 11 (12, 13) is executed by performing processing of each ECU 11 (12, 13) at a periodic timing acquired from the network time common to the network 10. High synchronicity is maintained in the processes executed by 13). As a result, when the communication information is time-division multiplexing, the synchronous communication system maintains the synchronization of the execution of the process when it is normal, and even if the periodic timing is not detected due to inconvenience in network communication, The synchronization of execution is maintained.

In addition, the said embodiment can also be implemented in the following aspects, for example.
In the above embodiment, the case where the general-purpose timer 23 operates based on the internal clock is illustrated. However, the present invention is not limited to this, and the general-purpose timer may be adjusted based on the network time. That is, as shown in FIG. 6, like the ECU 11 of the above-described embodiment, the ECU 30 includes a communication interface 34 having an arithmetic device 31, a storage device 32, a general-purpose timer 33, and a network timer 341. In the ECU 30, the general-purpose timer 33 may be provided with a synchronization circuit 331 that adjusts the length of the unit time according to the network time of the network timer 341. Thereby, the error between the unit time length of the network time measured by the network timer 341 and the unit time length of the general-purpose timer 33 is kept small, and the interrupt processing based on the trigger of the general-purpose timer 33 is performed. Even in this case, the synchronization of the execution of the synchronous application process is maintained at a high level.

In the above embodiment, the case where the synchronization application is executed based on the trigger of the general-purpose timer 23 when a problem occurs in the network is illustrated. However, the present invention is not limited to this, and if it is predicted that inconvenience will occur in the network, the synchronization application may be executed in advance based on the trigger of the general-purpose timer 23. That is, as shown in FIG. 7, a position information device 44 such as a navigation system is connected to a network 10 </ b> B of a vehicle 40 to which a plurality of ECUs 41 to 43 having the same configuration as the above embodiment is connected. In the position information device 44, a travel section in which the network 10B is easily affected by disturbance is registered as disturbance section information in advance as the travel environment of the vehicle 40, and the position information apparatus 44 registers the vehicle 40 in the disturbance section information. It is detected that the vehicle is traveling in the travel section. When it is detected that the vehicle 40 is traveling in the disturbance section, the position information device 44
May cause each of the ECUs 41 to 43 to temporarily stop detection of the periodic timing via the network 10B or the like and execute the processing of the synchronous application based on the generation of the trigger by the general-purpose timer. .

  According to such a configuration, when it is detected that the vehicle 40 is traveling in a disturbance section that is affected by disturbance in the network communication, the execution of each ECU 41 to 43 is executed by the trigger of each general-purpose timer. Do it. As a result, when it is anticipated in advance that the synchronization of the synchronous application process executed by each of the ECUs 41 to 43 is predicted, the synchronization of the process execution due to periodic non-detection or erroneous detection caused by disturbance It is possible to maintain the synchronization of the execution of the synchronous application process of each of the ECUs 41 to 43 while suppressing the decrease in the above.

  In the above embodiment, the case where the period C1 is 1 ms and the additional time α is 0.05 ms is exemplified, but the period and the additional time can be arbitrarily set according to the network and application, and the synchronization is maintained. Can be larger or smaller than 1 ms and 0.05 ms, respectively. Thereby, the freedom degree of the maintenance of the synchronization of the synchronous application process in a synchronous communication system is raised.

  In the above embodiment, the case where the periodic timing and the trigger are input to each of the plurality of interrupts of the arithmetic device 21 is illustrated. However, the present invention is not limited to this, and a periodic timing and a trigger may be input to one interrupt of the arithmetic device. In this case, the lengths of the signals of the periodic timing and the trigger may be made different, and based on the lengths, it may be determined which of the interrupt signals is based on. Thereby, the freedom degree of a structure of this synchronous communication system is raised.

  In the above embodiment, the case where the periodic timing is detected based on the network time is illustrated. However, the present invention is not limited to this, and the periodic timing may be any one that can be detected and maintained with high synchronization. For example, the periodic timing may be detected based on communication information such as a synchronization signal transmitted preferentially to the network. It may be. As a result, the synchronous communication system can be adopted even in a network in which the network time is not measured, and the adoption possibility is enhanced.

  In the above embodiment, the network 10 is illustrated with respect to the case where the communication path is wired. However, the present invention is not limited to this, and the network may be configured such that all or part of the communication path is configured by wireless communication. Thereby, the freedom degree of a structure of this synchronous communication system is raised.

  α ... additional time, P ... synchronous application, 10,10B ... network, 11, 12, 13, 30, 41-43 ... ECU (electronic processing unit), 21,31 ... arithmetic unit, 331 ... synchronous circuit, 22,32 ... Storage device, 23, 33 ... General-purpose timer, 24, 34 ... Communication interface, 241, 341 ... Network timer, 40 ... Vehicle, 44 ... Position information device.

Claims (6)

Each of a plurality of processing devices connected to the network detects a periodic timing based on communication information transmitted through the network, and executes processing so as to synchronize with the detected timing. A synchronous communication system that maintains synchronism with processing executed in synchronization with the timing in another connected processing device,
Each of the processing devices is reset each time the periodic timing is detected, and generates a trigger that causes the processing device to start executing the process based on the passage of a preset time after the reset. general-purpose timer is provided that, in the general-purpose timer, Ri name longer than the time of one period of said periodic timing is set as a timer time,
Each of the processing devices stops a periodic timing detection and generates a trigger in the general-purpose timer when an inconvenience is expected to occur in the network . The general-purpose timer is set to have a time longer than a time obtained by adding a time of one cycle of the periodic timing and an error time allowed for detection of the timing as the timer time. Synchronous communication system. The general-purpose timer is also reset when the trigger is generated by itself. Only when the trigger is reset by the trigger, the timer is set as one period of the periodic timing. The synchronous communication system according to claim 1 or 2, wherein a time equal to is set. Time division multiplexing communication information is transmitted to the network,
Each of the processing devices measures network time common to the network based on a time-division time interval of communication information transmitted by the time-division multiplexing method, and the period based on the network time. The synchronous communication system as described in any one of Claims 1-3 in which the network timer which acquires a specific timing is provided. The synchronous communication system according to claim 4, wherein the general-purpose timer has a unit time length adjusted for each corresponding processing device based on a network time acquired by the network timer. The network is an in-vehicle network mounted on a vehicle equipped with a navigation system, and a traveling section in which the network is easily affected by a disturbance is registered in advance as disturbance section information as a traveling environment of the vehicle. During the period when the system detects that the vehicle is traveling in the travel section registered in the disturbance section information, each of the processing devices predicts that a problem will occur in the network, The synchronous communication system according to any one of claims 1 to 5, wherein detection is temporarily stopped, and execution of the processing is continued based on generation of a trigger by the general-purpose timer.

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