Hi,
I'm seeing some odd behavior with the CAN-USB FD, hopefully someone can help tell if this is expected or not:
I'm trying to send a packet from PCAN-USB FD -> my device (STM32H750 + ADM3055E), in CAN FD BRS mode, nominal bit rate 1Mbps, data rate 4 Mbps.
I'm seeing what looks like an error frame being sent from the PCAN-USB FD (#1, 6us dominant), followed by an error frame from my board (#2, up to a few times, before my controller times out and stops responding).
This only seems to happen in CAN FD BRS mode, normal CAN seems to work fine, as well as non-BRS CAN FD.
I attached a screen grab and a Saleae Logic Analyzer grab, on my board's TTL side. RX is my RX, TX is my board's ack and error. There is an earlier good packet in the logic trace.
Sending from my board to the peak works reliably in all modes but FD BRS, and sometimes works in BRS mode. STD ids seem to work better than extended. Sometimes a EXT id packet will be received after trying 20-30 times, I attached a trace of that as well as pcanusbfd_rx_after_many_tries.
I'm confused why the PEAK would drive low for 6 bit times - I don't think there would be any reason for it to send an error, I'm not sure if something is wrong on my side.
Physical wiring is about 6-8 inches of loosely twisted (uncontrolled) wire, split termination installed on my board, feed-through grid connect branded Dsub termination on the PCAN side. I've played with the loop delay compensation on my side for transmission without much behavior change.
Any ideas would be helpful, thanks!