I'm using ATSAMC21J18A on a custom board, I used the Atmel Start, configured clock, IO's, and CAN BUS, all working fine, transmitting and receiving CAN BUS (CAN 2.0) data. But when I tried to change to CAN FD it is transmiting on CAN 2.0 and it is not receiving (did not set acknowledgement). I just changed the "FD OPERATION ENABLE" on "BASIC CONFIGURATION", with the previously working configuration. Do I have to change anything else to work with CAN FD? Bit rate switch is disabled. I'm using a TJA1048 CAN BUS transceiver (CAN FD prepared).
Also I noted that the Atmel Start Control Area Network(CAN) functionality implementation (hpl_can.c) do not consider the FDF bit in Write a CAN message function (_can_async_write). Is it missing code to CAN FD implementation?