Can message sending method, control unit, can node and its network

Abstract

The disclosure provides a CAN message sending method, a control unit, a CAN node and a network thereof. The method includes: setting the sending cycle range and the initial sending cycle of the CAN message under the identification corresponding to the current CAN node, and calculating all prime numbers within the sending cycle range; sending the CAN message by using the initial sending cycle, and Count the delay caused by the arbitration of the CAN message in the initial sending cycle; and in the case where the delay caused by the arbitration of the CAN message exceeds the set condition, find the closest to the initial sending cycle from all the calculated prime numbers The prime number of is used as the new sending cycle, and the new sending cycle is used to send the CAN message, and the delay caused by the arbitration of the CAN message in the new sending cycle is counted. The disclosure can dynamically adjust the timing of sending messages, reduce arbitration, and improve communication quality and data real-time performance.

Description

technical field [0001] The present disclosure relates to the field of CAN (Controller Area Network, controller area network) bus communication, and in particular, to a method for sending CAN messages, a control unit, a CAN node and a network thereof. Background technique [0002] At present, the application of CAN bus at home and abroad is more and more extensive, especially in the automotive and construction machinery industries, CAN bus communication is particularly important in data transmission occasions with high real-time requirements. The CAN bus uses non-destructive bus arbitration techniques, such as the "Carrier Sense, CSMA / CA (Carrier Sense Multiple Access with Collision Avoid, Carrier Sense Multiple Access with Collision Avoid)" communication mode. This bus arbitration method allows any node on the bus to have the opportunity to take control of the bus and send data out. If there are 2 or more nodes requesting to send data at the same time, bus conflicts will oc...

AI Technical Summary

Problems solved by technology

Although the CAN bus has an arbitration mechanism, before the arbitration is completed, multiple nodes send the arbitration segment data at the same time, and the signals will be superimposed, causing the amplitude to become larger, the signal to be deformed, and the communication quality to be reduced or errors to occur.

In addition, low-priority messages are waiting to be sent after arbitration, and they are sent immediately after the bus is idle. If there are multiple messages waiting to be sent, the bus load rate in this period will be too large, that is, the burst load rate is too large, which is easy to The phenomenon that the bus data is congested in a certain period of time and idle in the next period, such as figure 1 shown

For periodic packets, once this phenomenon occurs, it will continue to appear periodically, which has a great impact on the real-time performance of the network and packets

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