CAN FD Explained (2021)

Controller Area Network Flexible Data-Rate (CAN FD) is an improved communication bus with increased speed, length of data, reliability and smoother transition. It is also known as more advanced version of a classical CAN Bus. 


Welcome to our next episode of simple introduction articles, where we will be looking closely at CAN FD this time.


As previously, we have combined a professional knowledge of our engineers and research, and written it in a simple, but yet complex way to make it as easy as possible for you. 


In this CAN FD definitive guide, you will be able to find the definition of CAN FD, what it is, how does it work and so on. We have a surprise for you at the end of the article, so keep reading! 


the visual explanation of can fd

What is CAN FD?

CAN FD is a shortcut of Controller Area Network Flexible Data-Rate. It is a data communication protocol or also known as CAN FD protocol, commonly used for broadcasting sensor data and control information. 


how the classical can bus looks like

CAN FD protocol is typically used in modern high performance vehicles. Therefore, some experts explain CAN FD as a Lamborghini among Renaults (nothing personal to Renault drivers). 

CAN FD is an extension to the classical CAN Bus (ISO 11898-1. CAN FD protocol was developed back in 2011 and released by Bosch in 2012. 


The reason for developing the protocol was because of the increasing need of faster data transferring and therefore, it was developed to be capable of transferring data rate up to 5 times faster and with larger frames/messages. 


can fd illustrated easily in a simple picture of a car



CAN FD protocol is designed to efficiently receive and transmit sensor data, control commands and detect data errors among electronic sensor devices and CAN FD microcontrollers


At first, the protocol was developed for high performance vehicles, however, due to its improved data communication ability, we will see it in many other applications, such as robotics, industrial automation, marine vehicles, medical equipment and so on. 


Benefits of CAN FD

There are several great benefits of implementing CAN FD protocol. We will mention four main benefits below:


  • Smooth transition 

  • Increased reliability

  • Increased speed

  • Increased length of data bytes


Generally speaking, CAN FD can improve network bandwidth by 3 to 8 times more than a classical CAN.


As we already mentioned before, CAN FD can handle more data at a faster rate. Some of the common applications can be seen below:



The applications can be done by connecting the Telematics Unit to a OBD2 port in your vehicle. 


CAN FD vs CAN

The main difference between CAN FD and CAN is the flexible data. It means that using CAN FD, Electronic Control Units(ECUs) can easily switch to different data rates with either larger or smaller message sizes. 


CAN FD offers faster data speed and more data capacity enhancements than classical CAN. This usually applies on companies in need of using lots of data, where classical CAN might cause some issues. CAN FD becomes the solution for many businesses, due to their specific needs of transferring more amounts of data. 



an illustration of the key differences between can fd and classical can bus

SocketCAN

SocketCAN, formerly known as Low Level CAN Framework is a set of open source CAN drivers. Traditional CAN drivers are only allowed to send data to and receive from the CAN controller. Easily explained, it means that only single processes can occur, which means that all other processes are blocked. 

On the other side, SocketCAN allows multiple applications to access one CAN device, as well as one application to access multiple CAN networks, making the whole process much more effective and convenient. 

We are currently working on a new CAN FD device, which will be capable of all the things mentioned previously. Contact us for further info. 


CAN FD frame

CAN FD frame offers extra data bytes in addition to a classical CAN. Do you want to see the difference between a classical CAN frame and CAN FD frame? Then take a look below. 


As stated before, it is forecasted that CAN FD will take over classical CAN in the upcoming years. A couple of examples of CAN FD usage in the future can be seen below.


  • CANopen FD will be adopted via CiA 1301 1.0

  • J1939-22 will use CAN FD data frames

  • The first CAN FD capable cars are expected to be sold from 2021

  • CAN FD expected to be used in most of the new vehicles and other applications

  • Will use 2 Mbit/s and increasing to 5 Mbit/s


can fd frame illustration


As we see an increase in demand for CAN FD, we will be releasing a new product with CAN FD capability for your more advanced needs. Contact us if you want to kickstart your project with us and find out more details about the next generation device. 


Did you get the answers you were looking for? Contact us and let us know how we can improve. We look forward to hearing from you. 


Keep updated, we are working on more content like this one. 



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