Is it possible to determine whether a received CAN message is a CAN FD or a regular CAN message?

[lua40927]

Hello, I'm currently using an S32K312 .

I'm currently using the official sample code and have enabled FD for rx_info.

I've tried this configuration and it allows me to receive classic CAN messages (not CAN FD).

What I want to do now is determine whether a received message is a CAN FD message based on the received message.

I noticed that the received message declaration is as follows:

The only status I can view is "cs", but I can't find anything about "cs" in the manual.

If there are other methods to determine this without using "cs", please provide them to me.

Thanks

[PetrS]

Hi,

yes, the "cs" would contain that info, after reception it is loaded with MB's word0. MSB bit indicates if frame is classic CAN on CAN FD one.

BR, Petr

[lua40927]

Thank you for your reply.

I also want to ask, when CAN is set to CAN FD mode, is it possible to transmit classic CAN messages to older devices that do not support CAN FD? I disabled TX's fd and BRS, but the device is not receiving messages.

If it is possible, how should I configure it?

[PetrS]

Hi,

yes, it is possible, even if node has CAN FD mode enabled the classic CAN message can be sent. It is done as you wrote. Keep tx_info parameter to have fd_enable=false

and send message with this tx_info as parameter.

BR, Petr