On Mon, 03 May 2021 17:47:49 +0200, Marc Kleine-Budde wrote: > On 03.05.2021 15:31:34, Ayoub Kaanich wrote: > > For the ack bit, I think we could go with the bit being a “NO_ACK” > > bit, so a spy listener will set it to 1, if it receives a CAN frame, > > but it does not see any node in the bus acknowledging it. This way we > > preserve backward compatibility. > > As Vincent pointed out, the device should not receive the CAN frame that > has not been acked as I do on the flexcan. > > And even on the mcp251xfd, where I receive the CAN frame, there's no way > to tell if this frame has been acked or not. in listen-only mode, it's debatable if you should see an ack. If there's only 1 active node on the bus, you would not be able to probe the bitrate using listen-only mode, unless you accept CAN frames that are only miss the ACK bit. Kurt
