Time triggering module, communication node and method suitable for CAN bus

Abstract

The invention provides a time triggering module, a communication node and a method suitable for a CAN bus, and the time triggering module is integrated to or connected to an IP core of the CAN bus, and comprises a timing unit which is used for providing a global time reference and a basic period time reference; the time synchronization unit is used for synchronizing the timing value of the timing unit according to the reference message received from the time master node; the time window management unit is used for dividing the communication period into a plurality of time regions with different sending permissions according to the basic period time reference, and controlling the messages to be sent or processed in the corresponding time regions; and the timestamp unit is used for stamping a timestamp on the reference message generated by the time master node, so that the time synchronization unit performs time synchronization. According to the time triggering module provided by the invention, all units are coordinated through the full-hardware time triggering module, deterministic scheduling is realized, and the arbitration conflict of the CAN bus is fundamentally avoided.

Description

Technical Field

[0001] This disclosure generally relates to the field of digital chip design technology, and specifically to a time-triggered module, communication node, and method suitable for CAN bus. Background Technology

[0002] As a high-real-time serial communication bus, the CAN bus has been widely used in automotive electronics, industrial control, and aerospace. With increasing system integration and the growing number of bus nodes, priority-based arbitration mechanisms may prevent low-priority nodes from gaining bus access, affecting communication determinism. To address this, the ISO 11898-4 standard proposed the Time-Triggered CAN (TTCAN) protocol, aiming to achieve more reliable and predictable communication through global time synchronization and scheduling.

[0003] However, traditional CAN nodes typically lack hardware support for the TTCAN protocol. If the time-triggered function is implemented solely through software, it will consume processor resources, increase response latency, and make it difficult to guarantee the accuracy of time synchronization and the reliability of scheduling execution. This limits the application effectiveness of TTCAN in scenarios with strict real-time requirements. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a time-triggered module, communication node and method suitable for CAN bus to solve the above problems.

[0005] The first aspect of this application provides a time-triggered module suitable for a CAN bus, integrated into or connected to a CAN bus IP core, comprising: Timing unit, used to provide a global time base and a basic periodic time base; A time synchronization unit, connected to the timing unit, is used to synchronize the timing value of the timing unit according to the reference message received from the time master node; The time window management unit, connected to the timing unit, is used to divide the communication period into multiple time zones with different sending permissions according to the basic periodic time base, and control the transmission or processing of messages in the corresponding time zones. The timestamp unit, associated with the timing unit and the time synchronization unit, is used to timestamp the reference messages generated by the time master node so that the time synchronization unit can perform time synchronization. The time-triggered module coordinates the timing unit, time synchronization unit, time window management unit, and timestamp unit to achieve time-triggered message scheduling, thereby avoiding bus arbitration conflicts.

[0006] According to the technical solution provided in the embodiments of this application, the timing unit includes a global timer obtained by dividing the bus clock and a basic periodic timer obtained by configurable shifting operations on some bits of the global timer.

[0007] According to the technical solution provided in the embodiments of this application, the time synchronization unit is configured as follows: When this node acts as a time slave node, it updates the value and counting frequency of its global timer based on the timestamp in the received reference message.

[0008] According to the technical solution provided in the embodiments of this application, the process of updating the counting frequency includes: comparing the timestamp difference of the reference messages received in two consecutive basic periods with the global timer difference at the corresponding time of this node, and dynamically adjusting the frequency division parameter of the global timer.

[0009] According to the technical solution provided in the embodiments of this application, the time region divided by the time window management unit includes at least: The reference message area is dedicated to transmitting reference messages that carry timestamps. A dedicated area that allows message transmission and does not automatically retransmit if transmission fails. The arbitration area allows message transmission and can automatically retransmit if transmission fails.

[0010] According to the technical solution provided in the embodiments of this application, the time region further includes a stop region and a prohibition region, in which nodes are prohibited from sending messages.

[0011] According to the technical solution provided in the embodiments of this application, the start and end time boundaries of each time zone are configured independently through registers, and the boundaries of different zones are allowed to overlap, so as to form a communication scheduling matrix that adapts to different system requirements.

[0012] A second aspect of this application provides a CAN bus communication node, including a CAN bus IP core and a time-triggered module for CAN bus as described above.

[0013] A third aspect of this application provides a time-triggered communication method based on a CAN bus, applied to the time-triggered module suitable for a CAN bus as described above, the method comprising: Establish a local time reference using timing units; The time master node embeds its global timestamp in the reference message through timestamp units and broadcasts it. The time node receives the reference message through the time synchronization unit and synchronizes the local timing unit according to the timestamp therein; Each node sends or processes messages within the designated time zone according to the time zone plan preset by the time window management unit.

[0014] According to the technical solution provided in the embodiments of this application, the synchronous local timing unit includes a synchronous timing value and a synchronous timing frequency.

[0015] Compared with existing technologies, the advantages of this application are as follows: By integrating a timing unit, a time synchronization unit, a time window management unit, and a timestamp unit, a fully hardware time triggering module is constructed, providing complete TTCAN function support for the CAN bus IP core. Based on a unified global time base and combined with a configurable time window scheduling mechanism, this module enables each node to send messages within a pre-allocated, defined time window. This fundamentally avoids the message transmission delay, uncertainty, and even system livelock problems caused by multi-node contention arbitration in traditional CAN buses, significantly improving the real-time performance, determinism, and overall reliability of bus communication. This hardware implementation is highly efficient, requires no software intervention, and is easy to integrate or upgrade to existing CAN nodes. Attached Figure Description

[0016] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a time-triggered module suitable for CAN bus provided in Example 1; Figure 2 This is a schematic diagram of the timing unit's operation. Figure 3 This is a diagram illustrating the time region. Figure 4 Example diagram for applying time zones; Figure 5 The flowchart illustrates the steps of the time-triggered communication method based on the CAN bus provided in Example 2.

[0017] The reference numerals are as follows: 10, Timing Unit; 20, Time Synchronization Unit; 30, Time Window Management Unit; 40, Timestamp Unit; 50, Data Transmission and Reception Module. Detailed Implementation

[0018] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] Example 1 Please refer to Figures 1-4 This application provides a time-triggered module suitable for CAN bus, integrated into or connected to a CAN bus IP core, including: Timing unit 10 is used to provide a global time base and a basic periodic time base; The time synchronization unit 20 is connected to the timing unit 10 and is used to synchronize the timing value of the timing unit 10 according to the reference message received from the time master node. The time window management unit 30 is connected to the timing unit 10 and is used to divide the communication period into multiple time regions with different sending permissions according to the basic period time reference, and control the transmission or processing of messages in the corresponding time regions. The timestamp unit 40, associated with the timing unit 10 and the time synchronization unit 20, is used to timestamp the reference message generated by the time master node so that the time synchronization unit 20 can perform time synchronization. The time-triggered module coordinates the timing unit 10, time synchronization unit 20, time window management unit 30, and timestamp unit 40 to achieve time-triggered message scheduling, thereby avoiding bus arbitration conflicts.

[0021] Specifically, the time-triggered module provided in this embodiment is integrated into or connected to the CAN bus IP core, and its overall structure can be found in the appendix. Figure 1 The schematic diagram shows that the core consists of a timing unit 10, a time synchronization unit 20, a time window management unit 30, and a timestamp unit 40. Each unit works with the external data transceiver module 50 to complete the time-triggered communication scheduling of the CAN bus. The data transceiver module 50 receives and sends data through the TX / RX bus, providing external data transmission support for the module's operation. The timing unit 10, as the time-based component of the module, is responsible for providing a global time reference and a basic periodic time reference for the entire CAN bus node, and is the core time basis for the implementation of the time triggering function. The time synchronization unit 20 is connected to the timing unit 10, and can receive reference messages from the time master node, and adjust the timing value of the timing unit 10 synchronously according to the message to ensure the consistency of the time reference of each node. The time window management unit 30 is also connected to the timing unit 10, and divides the communication period based on the basic periodic time reference, and manages the message sending and processing flow by setting time areas with different sending permissions. The timestamp unit 40 is associated with the timing unit 10 and the time synchronization unit 20, and mainly adds timestamps to the reference messages generated by the time master node, providing data support for the time synchronization operation of the time synchronization unit 20.

[0022] In actual operation, the time-triggered module coordinates the workflows of the timing unit 10, time synchronization unit 20, time window management unit 30, and timestamp unit 40 to achieve time-triggered message scheduling. After the CAN bus IP core powers on and the user completes register configuration, the timing unit 10 first starts the global and basic periodic time bases. The time master node sends a timestamped reference message through the timestamp unit 40, while the time slave nodes synchronize their local timing values ​​through the time synchronization unit 20. Subsequently, each node sends or processes messages within the designated area according to the time area plan preset by the time window management unit 30. This fully hardware-based collaborative approach allows each node to transmit messages within a pre-allocated time window, fundamentally avoiding the bus contention problem caused by traditional CAN bus multi-master arbitration, effectively preventing bus arbitration conflicts, and improving the real-time performance, accuracy, and reliability of CAN bus message transmission.

[0023] Furthermore, the timing unit 10 includes a global timer obtained by dividing the bus clock and a basic periodic timer obtained by configurable shift operations on a portion of the bits of the global timer.

[0024] Specifically, the internal structure of the timing unit 10 can be found in the attached document. Figure 2 It includes two core timers: an M-bit global timer and an N-bit basic periodic timer (where M ≥ N). The global timer's counting clock is derived from a frequency division of the bus clock. The frequency division parameter can be flexibly configured via registers. Users can set appropriate frequency division values ​​to adjust the global timer's counting accuracy according to the actual communication rate requirements of the CAN bus system. The global timer is updated in two ways: one is by directly initializing the counting start point through a preset value configured in the register; the other is by updating the value based on the time information in the reference message when the time synchronization unit 20 completes the time synchronization operation. Furthermore, the global timer employs an overflow clearing mechanism to ensure the continuous cyclic counting of the time.

[0025] The basic cycle timer in timing unit 10 is based on the lower N bits of the global timer. It is generated through configurable shift operations (shift parameters are independently configured by registers). For example, depending on the system's requirements for the basic cycle length, the lower N bits of the global timer can be shifted left by 1 or more bits to match different basic cycle time bases. The update and reset logic of this basic cycle timer corresponds to two scenarios: first, it is updated synchronously with the change of the global timer value to ensure correlation with the global time base; second, it is reset when the time window management unit 30 triggers a reset instruction, or when the basic cycle area ends (i.e., when the basic cycle timer counts to the end of the set cycle), to ensure that the timing start point of each basic cycle is uniform, providing a stable cycle base for subsequent time window division and message scheduling.

[0026] Furthermore, the time synchronization unit 20 is configured as follows: When this node acts as a time slave node, it updates the value and counting frequency of its global timer based on the timestamp in the received reference message.

[0027] Specifically, the time synchronization unit 20 is connected to the timing unit 10, and one of its core functions is to perform time calibration for scenarios where this node acts as a time slave node. This working logic needs to be combined with the attached... Figure 1 The relationship between the time synchronization unit 20 and other units is realized. When this node is a time slave node, it cannot determine the global time base independently and needs to rely on the reference message broadcast by the time master node. The timestamp carried in the reference message is generated by the timestamp unit 40 (that is, the value obtained by the time master node from sampling the global timer at the SOF point of the reference message). After the time slave node receives the reference message through the external data transceiver module 50, the time synchronization unit 20 will first extract the timestamp information in the message as the basis for calibrating the local time.

[0028] During the synchronization process, the time synchronization unit 20 updates the timing value of the timing unit 10 in two ways based on the extracted timestamp: firstly, it updates the global timer value, directly replacing the current value of the local global timer with the master node's global timer value corresponding to the reference message timestamp, ensuring that the slave node and the master node are consistent in time values; secondly, it synchronizes the associated basic period timer, adjusting the reset point of the local basic period timer to the SOF point of the reference message, aligning the basic period start point of the slave node with the master node. Through these two updates, the global time base and basic period time base of the time slave node are synchronized with the master node, providing a prerequisite for subsequent message sending by each node according to a unified time plan and avoiding scheduling chaos caused by time deviation.

[0029] Furthermore, the process of updating the counting frequency includes: comparing the timestamp difference of the reference messages received within two consecutive basic periods with the global timer difference at the corresponding moment of the current node, and dynamically adjusting the frequency division parameter of the global timer.

[0030] Specifically, the process of updating the global timer counting frequency from the node essentially involves dynamic calibration by comparing time data from two consecutive basic cycles. This process relies on... Figure 1 The data flow interaction between the time synchronization unit 20 and the timing unit 10, and the attached Figure 2The global timer operates based on the bus clock frequency division logic. When the time slave node needs to bring its local global timer counting frequency closer to that of the time master node, it will collect data in units of basic cycles: at the SOF (Start of Frame) point of the reference message in the Xth basic cycle, the time synchronization unit 20 will simultaneously record two sets of data—the master node global timer timestamp carried in the reference message (denoted as the a value of the reference message) and the current value of the global timer of the local timing unit 10 (denoted as the local a value); when entering the SOF point of the reference message in the (X+1)th basic cycle, the above collection operation is repeated to obtain the b value of the reference message and the local b value.

[0031] After data acquisition, the time synchronization unit 20 performs difference calculation and ratio analysis on the two sets of data: first, it calculates the difference between the local global timer ("local b value - local a value") and the difference between the master node timestamp ("reference message b value - reference message a value"); then, it divides the local difference by the reference message difference to obtain the corresponding quotient and remainder. The "quotient" in the calculation result is used to dynamically adjust the frequency division parameter of the global timer in the timing unit 10, while the "remainder" is used to fine-tune the frequency division step of the global timer to ensure the accuracy of frequency adjustment. The above parameter adjustment operation is completed within the (X+2)th basic cycle, ultimately causing the counting frequency of the local global timer to gradually approach that of the master node, avoiding long-term time asynchrony caused by frequency deviation, and further improving the consistency of the time base of each node.

[0032] Furthermore, the time regions divided by the time window management unit 30 include at least: The reference message area is dedicated to transmitting reference messages that carry timestamps. A dedicated area that allows message transmission and does not automatically retransmit if transmission fails. The arbitration area allows message transmission and can automatically retransmit if transmission fails.

[0033] Specifically, the time window management unit 30 is connected to the timing unit 10, and its core basis for dividing time regions is the basic periodic time reference provided by the timing unit 10. The division results can be found in the appendix. Figure 3 The basic area structure shown includes at least three core areas: a reference message area, a dedicated area, and an arbitration area. The functions and sending permissions of each area are designed to "avoid bus arbitration conflicts and improve message scheduling determinism." The reference message area is a function-dedicated area used only for transmitting timestamped reference messages sent by the time master node. This message is generated by the time master node through the timestamp unit 40 (sampling the global timer value at the reference message SOF point). If any node fails to complete the transmission or reception of the reference message by the end of the reference message area, the time window management unit 30 will trigger an error interruption report to ensure reliable transmission of the reference message and provide a guarantee for subsequent time synchronization.

[0034] The dedicated zone and arbitration zone are designed to address different message transmission needs in different scenarios: In the dedicated zone, nodes are allowed to send specific preset messages, but message transmission in this zone follows a "no automatic retransmission upon failure" rule. If a message transmission fails due to a sudden anomaly, the time window management unit 30 only records the failure event and does not trigger a retransmission operation, avoiding the consumption of subsequent time resources due to retransmission; while the arbitration zone, as a supplementary and fault-tolerant area for message transmission, not only allows nodes to send new messages, but also supports sending messages that failed to be sent in the dedicated zone, and message transmission in this zone follows a "automatic retransmission upon failure" rule, ensuring the reliability of critical message transmission. (Appendix) Figure 4 Example 1 (applicable to systems with few nodes and uncertain message count) and Example 2 (applicable to systems with many nodes and a fixed message count) both use these three types of core regions as the basis for boundary configuration, further demonstrating the adaptability of this region division logic to the needs of different systems.

[0035] Furthermore, the time region also includes a stop zone and a prohibition zone, in which nodes are prohibited from sending messages.

[0036] Specifically, the time areas divided by the time window management unit 30, in addition to the reference message area, dedicated area, and arbitration area, may further include a stop area and a prohibited area. The functional definitions and locations of these two types of areas can be found in the appendix. Figure 3 The complete area structure shown here functions by setting buffer intervals or risk interception segments within the communication cycle through rules that enforce the prohibition of transmission, thus preventing unexpected packets from interfering with the communication order of the core area. The stop area is typically divided into Stop Area 1 and Stop Area 2, and... Figure 3 In the basic structure, Stop Zone 1 is generally located between the Reference Message Zone and the Dedicated Zone, while Stop Zone 2 is located between the Dedicated Zone and the Arbitration Zone. Both types of Stop Zones follow the same rules, namely, nodes are prohibited from sending any messages. They are not allowed to initiate the transmission of new messages or allow residual messages to continue to be transmitted. They serve only as isolation intervals between different functional areas to prevent delayed messages from the previous area from occupying the time resources of the next area. For example, entering Stop Zone 2 after the Dedicated Zone ends can prevent invalid transmissions in the Dedicated Zone from interfering with the normal message transmission in the Arbitration Zone.

[0037] The prohibited zone is the final control part of the communication cycle. Its prohibition rules are stricter than those of the stop zone. Besides prohibiting nodes from sending any messages, the time window management unit 30 will also perform a combination of operations—canceling transmission, recording information, and triggering an error interrupt—for messages already in the transmission queue. If a message fails to be transmitted in the dedicated zone or arbitration zone due to scheduling delays, it will be directly disqualified from transmission upon entering the prohibited zone. Simultaneously, the time window management unit 30 will record the message's identifier, transmission time, and other information, and trigger an error interrupt to report to the system so that users can investigate the cause of the delay. The configuration of both types of zones can also be combined with the attached... Figure 4 The scene can be flexibly adjusted, for example, attached Figure 4 In Example 1, the boundaries of Stop Area 1, Dedicated Area, and Stop Area 2 can be configured to overlap, so that the system only retains the Reference Message Area, Arbitration Area, and Prohibited Area, which is suitable for scenarios with a small number of nodes and an uncertain number of messages. In Example 2, the start and end times of Stop Area 1 and 2 can be adjusted so that the dedicated areas of different nodes can be connected sequentially. At the same time, the dedicated area transmission of each node is isolated by the Stop Area, ensuring the communication order in multi-node scenarios.

[0038] Furthermore, the start and end time boundaries of each time zone are configured independently through registers, and the boundaries of different zones are allowed to overlap, so as to form a communication scheduling matrix that can adapt to different system requirements.

[0039] Specifically, the start and end time boundaries of the various time zones divided by the time window management unit 30 are independently configured through registers. That is, the start and end times of the reference message zone, stop zone, dedicated zone, arbitration zone, and prohibited zone each correspond to independent register parameters. Users can adjust the time range of a specific zone individually according to the actual needs of the CAN bus system, such as the number of nodes, message type, and transmission priority, without needing to modify other zones in conjunction. For example, regarding the attached... Figure 3 The basic area structure can be configured by extending or shortening the communication cycle duration of the reference message area to adapt to scenarios with changes in the amount of reference message data. Alternatively, the time range of the dedicated area can be expanded by adjusting the register parameters of the dedicated area to accommodate the sending needs of more specific messages. The time window management unit 30 will accurately define the time boundaries of each area in each basic cycle based on these configuration parameters to ensure that messages are only allowed or prohibited from being sent within the preset area.

[0040] The boundaries of various time zones are allowed to overlap, meaning the start and end time ranges of different zones can partially or completely overlap. This design allows the time window management unit 30 to flexibly construct a communication scheduling matrix according to system requirements. (See attached...) Figure 4In Example 1, by configuring the start and end time boundaries of Stop Area 1, Dedicated Area, and Stop Area 2 to completely overlap, the three originally independent areas are merged into a transition segment without isolation intervals. Ultimately, the system only retains the Reference Message Area, Arbitration Area, and Prohibited Area. This overlapping configuration is suitable for scenarios with a small number of nodes and an uncertain number of messages, reducing the time loss caused by area switching. In Example 2, by adjusting the start and end boundaries of Stop Area 1 and Stop Area 2 of different nodes, the Stop Area 1 of some nodes partially overlaps with the dedicated area boundary of another node. This allows the dedicated areas of each node to connect sequentially within the communication cycle without idle intervals. This configuration is suitable for scenarios with a large number of nodes and a fixed number of messages, maximizing the utilization of bus communication resources. Through the above flexible boundary configuration and overlapping design, the Time Window Management Unit 30 can form a communication scheduling matrix that adapts to different system requirements, ensuring the module's compatibility and practicality in diverse application scenarios.

[0041] Example 2 Based on the above embodiment 1, this embodiment provides a CAN bus communication node, including a CAN bus IP core and a time triggering module suitable for CAN bus as described in any one of claims 1-7.

[0042] Specifically, the core components of the communication node provided in this embodiment include a CAN bus IP core and a time-triggered module suitable for the CAN bus as described in Embodiment 1. The two interact with data and control commands through an internal signal link. The overall architecture can be combined with the attached... Figure 1 Understanding – The CAN bus IP core, as the basic communication component of the node, is responsible for message parsing, encapsulation, and bus physical layer interaction functions, while the time trigger module provides it with time reference and scheduling control capabilities. Together, they achieve reliable communication in accordance with the TTCAN protocol.

[0043] Example 3 Please refer to Figure 5 Based on Embodiment 1 above, this embodiment provides a time-triggered communication method based on a CAN bus, applied to a time-triggered module suitable for a CAN bus as described in any one of claims 1 to 7, the method comprising: S100: Establish a local time reference through timing unit 10; S200: The time master node embeds its global timestamp in the reference message through timestamp unit 40 and broadcasts it; S300: The time slave node receives the reference message through the time synchronization unit 20 and synchronizes the local timing unit 10 according to the timestamp therein; S400: Each node sends or processes messages within the specified time area according to the time area plan preset by the time window management unit 30.

[0044] Specifically, the communication method provided in this embodiment relies on the time-triggered module described in Embodiment 1. The overall process is closely related to the collaborative logic of each unit of the module, and can be combined with the appendix. Figure 1 and appendix Figure 2 Understand the core steps. When the method starts, a local time base is first established through the timing unit 10 of the time trigger module. The timing unit 10 divides the bus clock according to the preset frequency division parameters in the register to generate the counting clock of the global timer. At the same time, a basic periodic timer is generated by configurable shifting operation on the lower N bits of the global timer. The two together constitute the time base of the local node, providing a time basis for subsequent communication scheduling.

[0045] When the local node is the time master node, it performs reference message processing through the timestamp unit 40: at the beginning of the reference message area of ​​the basic cycle, the timestamp unit 40 samples the global timer value of the timing unit 10 at the SOF point of the reference message, embeds it into the reference message data frame, and broadcasts it to the bus through the external data transceiver module 50; the time slave node receives the reference message through the time synchronization unit 20 and synchronizes the global timer value of the local timing unit 10 with the basic cycle timer reset point according to the timestamp in the message. After completing the time synchronization, each node sends or processes messages in the designated area according to the time area plan preset by the time window management unit 30; for example, sending preset messages in the dedicated area and retransmitting failed messages in the arbitration area, ultimately realizing time-triggered ordered communication. This method also constitutes the core content of Embodiment 3. Through the combination of modules and methods, bus arbitration conflicts are effectively avoided, adapting to the real-time requirements of scenarios such as automobiles and industrial control.

[0046] Furthermore, the synchronous local timing unit 10 includes a synchronous timing value and a synchronous timing frequency.

[0047] Specifically, the time is synchronized from the node to the local timing unit 10. The core consists of two parts: the synchronized timing value and the synchronized timing frequency. This can be combined with the attached... Figure 1 With appendix Figure 2 Understanding. When synchronizing timing values, after receiving the master node's reference message from the slave node, the time synchronization unit 20 extracts the timestamp generated by the timestamp unit 40 from the message, directly updates the global timer value of the timing unit 10, and adjusts the basic cycle timer's reset point to the reference message SOF point, achieving time start alignment. When synchronizing the timing frequency, the time synchronization unit 20 records the reference message timestamp and the local global timer value at the reference message SOF points of the X and X+1 basic cycles, respectively. After calculating the difference between the two, the quotient of the difference is used to adjust the frequency division parameter of the global timer of the timing unit 10, and the remainder is used to fine-tune the frequency division step. The update is completed in the X+2 basic cycle. Dual synchronization ensures long-term consistency between the local and master node times, avoiding scheduling chaos.

[0048] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A time-triggered module suitable for CAN bus, integrated into or connected to a CAN bus IP core, characterized in that, include: Timing unit (10) is used to provide a global time base and a basic periodic time base; A time synchronization unit (20) is connected to the timing unit (10) and is used to synchronize the timing value of the timing unit (10) according to the reference message received from the time master node; The time window management unit (30) is connected to the timing unit (10) and is used to divide the communication cycle into multiple time zones with different sending permissions according to the basic cycle time reference, and control the message to be sent or processed in the corresponding time zone. The timestamp unit (40), associated with the timing unit (10) and the time synchronization unit (20), is used to timestamp the reference message generated by the time master node so that the time synchronization unit (20) can perform time synchronization. The time-triggered module coordinates the timing unit (10), time synchronization unit (20), time window management unit (30), and timestamp unit (40) to achieve time-triggered message scheduling in order to avoid bus arbitration conflicts.

2. The time-triggered module for CAN bus according to claim 1, characterized in that, The timing unit (10) includes a global timer obtained by dividing the bus clock and a basic periodic timer obtained by configurable shift operations on a portion of the bits of the global timer.

3. The time-triggered module for CAN bus according to claim 1, characterized in that, The time synchronization unit (20) is configured as follows: When this node acts as a time slave node, it updates the value and counting frequency of its global timer based on the timestamp in the received reference message.

4. The time-triggered module for CAN bus according to claim 3, characterized in that, The process of updating the counting frequency includes: comparing the timestamp difference of the reference messages received within two consecutive basic periods with the global timer difference at the corresponding moment of the current node, and dynamically adjusting the frequency division parameter of the global timer.

5. The time-triggered module for CAN bus according to claim 1, characterized in that, The time regions divided by the time window management unit (30) include at least: The reference message area is dedicated to transmitting reference messages that carry timestamps. A dedicated area that allows message transmission and does not automatically retransmit if transmission fails. The arbitration area allows message transmission and can automatically retransmit if transmission fails.

6. The time-triggered module for CAN bus according to claim 5, characterized in that, The time zone also includes a stop zone and a prohibition zone, in which nodes are prohibited from sending messages.

7. The time-triggered module for CAN bus according to claim 5 or 6, characterized in that, The start and end time boundaries of each time zone are configured independently through registers, and the boundaries of different zones are allowed to overlap to form a communication scheduling matrix that can adapt to different system requirements.

8. A CAN bus communication node, characterized in that, It includes a CAN bus IP core and a time-triggered module suitable for CAN bus as described in any one of claims 1-7.

9. A time-triggered communication method based on CAN bus, characterized in that, The method, applied to a time-triggered module suitable for a CAN bus as described in any one of claims 1 to 7, comprises: A local time reference is established through the timing unit (10); The time master node embeds its global timestamp in the reference message through the timestamp unit (40) and broadcasts it; The time node receives the reference message through the time synchronization unit (20) and synchronizes the local timing unit (10) according to the timestamp therein. Each node sends or processes messages within the specified time zone according to the time zone plan preset by the time window management unit (30).

10. The time-triggered communication method for CAN bus according to claim 9, characterized in that, The synchronous local timing unit (10) includes synchronous timing values ​​and synchronous timing frequency.

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