Add support for CAN-FD

[thirtytwobits]

I'd like to use the portenta x8 to connect to CAN-FD networks. Can you add support for CAN FD in the device drivers for the Portenta?

[aentinger]

Hi @thirtytwobits ☕ 👋

Thank you very much for reaching out. While the Portenta X8 does support CAN FD on the hardware side, the corresponding firmware and Linux device driver currently only support CAN "Classic". In order to enable CAN FD support a some of development work would need to be invested.

Can you please tell us a bit about your application?

[thirtytwobits]

Sure. We use CAN-FD as a message bus on robotics systems where the larger MTU allows us to trade latency for reduced protocol overhead and vice-versa. Furthermore, we use a higher bitrate for the data-section (BRS) to further reduce latency by shortening transmission times. Finally, the improved checksum provides additional robustness that we find desirable.

Standard bitrates in automotive these days seems to be around 500kbs arbitration with 2Mbs data but, as you know, FD should support data rates up to 5Mbs.

Does that help?