Communication tutorial | overview of the first, second and third generation can bus

Focus on + Star sign public Number , Don't miss the highlights

Video Number | strongerHuang

WeChat official account  | strongerHuang

CAN It's more and more widely used , Automotive electronics 、 Industrial control 、 Large instruments and equipment can be seen everywhere CAN Bus .

1986 year ： Launched CAN Bus ;

2012 year ： Launched CAN FD;

2020 year ： A new generation of CAN XL;

first generation CAN

CAN：Controller Area Network, Controller area network , It belongs to industrial fieldbus , yes ISO International standard serial communication protocol .

CAN Fieldbus is one of the most widely used Fieldbus in the world , At present, it has become the standard bus of automotive computer control system and embedded industrial control LAN .

from OSI（Open System Interconnection Open systems interconnection ）7 From the perspective of layer network model ,CAN field bus Only the second 1 layer （ The physical layer ） And the 2 layer （ Data link layer ）.

I have written a lot about CAN And CANOpen The content of , You can search on my official account homepage , Or backstage reply “CAN” See more .

Second generation CAN

CAN FD：CAN with Flexible Data-Rate, Translated into Variable speed CAN.

In the classic CAN Increase the transmission rate on the basis of , Data fields can be transferred 64byte, That is, the variable speed function , yes CAN Upgraded version .

CAN FD Two ways are adopted to improve the efficiency of communication ：

• Shorten bit time and improve bit rate ;

• Lengthen the length of the data field, reduce the number of messages, and reduce the bus load rate .

stay CRC Three polynomials are used in the verification section to ensure the data reliability under high-speed communication .

Refer to the official website ：

https://www.can-cia.org/can-knowledge/can/can-fd

The first generation and the second generation CAN difference

1. Data bits are different

• CAN： One frame of data is the longest 8 byte

• CAN FD： One frame of data is the longest 64 byte

2. Different speeds

• CAN： Maximum 1Mbit/s

• CAN FD： Greater than 1Mbit/s

（ In the arbitration stage , Limit to 1 Mbit/s）

Of course , Except for the difference of data bits , And variable rate 、 The frame format is different , For details, please refer to the official documents ：

www.can-cia.org

The third generation CAN

Following CAN、 CACN FD after , stay 2020 year 1 month ,CiA A new generation of CAN XL.

CAN XL A will be provided Maximum 2048 Byte data field . The network layer can 11 The bit priority field is used for addressing purposes , And indicate the content of the data field .

CAN XL The frame passes through two CRC（ Cyclic redundancy check ） To protect , Five randomly distributed error codes can be detected .

CAN XL It is a highly scalable communication technology , Involving bit rate and length of data field . The physical layer is still under development . The goal is to reach as high as 10+ Mbit/s Bit rate of .

CAN XL Optimize the heterogeneous network architecture for the region , This scheme can meet the optimization requirements of the future vehicle network length , Reduce cabling .

For more details , Please refer to ：

https://www.can-cia.org/can-knowledge/can/can-xl

https://www.can-cia.org/news/cia-in-action/view/can-xl-is-knocking-on-the-door/

------------ END ------------

Focus on official account back office reply 『 Communication course 』『 Single chip microcomputer 』 Read more about it .

reply “ Add group ” Join the technical exchange group according to the rules , reply “1024” See more .

Click on “ Read the original ” See more sharing .