[CAN-FD] Vehicle Diagnostic Communication Part 85 [Overview 1]

Click here for back issues.
https://www.simulationroom999.com/blog/diagnostic-communication-en-back-issue/

Introduction.
Different physical and data link layers from CAN
CAN-FD Overview
Important Points for CAN-FD
Conclusion.

Introduction.

We will now enter into the explanation of CAN-FD.
I will begin with overview.

Different physical and data link layers from CAN

Now that we are done with the AUTOSAR-DCM simulations, we are done with this series!

But in fact, there is still some work to be done there.
That is the case where the physical and data link layers are other than CAN.
But, it’s just to change CAN to CAN-FD. (Not to Ethernet or anything.)

CAN-FD Overview

Some of you may know CAN, but only know CAN-FD by name.
Since the name is similar, you may think that the specifications are also similar.
Well, that idea is not far off the mark.

In fact, it is lightly described in Vector’s “CAN/CAN-FD for Beginners.”
(The title of the book is “CAN-FD,” so it is only natural.)

https://www.vector.com/jp/ja/know-how/vj-beginners/cancan-fd/

For now, it is OK if you read this.

Although there are some differences, it should be enough for simulation.

Important Points for CAN-FD

Let me tell you some important points when you read ” CAN/CAN-FD for Beginners.”.

When compared to CAN, the differences are roughly as follows

CAN frames can be transmitted and received as part of the CAN-FD specification.
Length of one frame extended from a maximum of 8[byte] to 64[byte].
In CAN, DLC indicates the frame size, but this is not necessarily true for CAN-FD.
- DLC=8: 8[byte]
- DLC=9: 12[byte]
- DLC=14: 48[byte]
- DLC=15: 64[byte]
Flag indicating that it is a CAN-FD and the flag that becomes FlexDataRate are different
- FDF (FD Format Indicator): Flag indicating CAN-FD
- BRS (Bit Rate Switch): Becomes FlexDataRate. (FDF must be enabled)