CAN message sending method, control unit, CAN node and network thereof

Abstract

The invention provides a CAN message sending method, a control unit, a CAN node and a network thereof. The method comprises the following steps: setting a sending period range and an initial sending period of a CAN message under an identifier corresponding to a current CAN node, and calculating to obtain all prime numbers in the sending period range; sending the CAN message by adopting the initial sending period, and counting the situation of delay caused by arbitration of the CAN message in the initial sending period; and when the situation that the CAN message is arbitrated to cause delay exceeds a set condition, searching a prime number closest to the initial sending period from all the prime numbers obtained by calculation as a new sending period, sending the CAN message by adopting the new sending period, and counting the situation that the CAN message is arbitrated to cause delay in the new sending period. According to the invention, the message sending time can be dynamically adjusted, arbitration is reduced, and the communication quality and the data real-time performance are improved.

Description

technical field [0001] The present disclosure relates to the field of CAN (Controller Area Network, Controller Area Network) bus communication, in particular to a CAN message sending method, 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 automobile and construction machinery industries, CAN bus communication is particularly important in data transmission occasions with high real-time requirements. The CAN bus adopts non-destructive bus arbitration technology, such as "carrier monitoring, CSMA / CA (Carrier Sense Multiple Access with Collision Avoid, Carrier Sense Multiple Access with Collision Avoidance)" communication mode. This bus arbitration method allows any node on the bus to have the opportunity to obtain control of the bus and send data to the outside. If there are 2 or more nodes requesting to send data at the same time, there will ...

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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