our CANFD timings were resulting in a lot of busoff errors. Here is an
example of master at 1Mbit/5MBit:
Getting @SYS/can0_stats.txt as -
------- Clock Config -------
CAN_CLK_FREQ: 80MHz
Std Timings: bitrate=1000000 presc=7
sjw=0 bs1=7 bs2=0 sample_point=90.00000%
FD Timings: bitrate=5000000 presc=1
sjw=0 bs1=5 bs2=0 sample_point=90.00000%
------- CAN Interface Stats -------
tx_requests: 2689
tx_rejected: 0
tx_overflow: 443
tx_success: 7
tx_timedout: 2232
tx_abort: 0
rx_received: 18470
rx_overflow: 0
rx_errors: 0
num_busoff_err: 34439
num_events: 18477
ECR: F8
fdf_rx: 18467
fdf_tx_req: 2182
fdf_tx: 0
here is an example with the new timings:
------- Clock Config -------
CAN_CLK_FREQ: 80MHz
Std Timings: bitrate=1000000 presc=8
sjw=1 bs1=8 bs2=1 sample_point=90.00000%
FD Timings: bitrate=8000000 presc=2
sjw=3 bs1=8 bs2=3 sample_point=80.00000%
------- CAN Interface Stats -------
tx_requests: 3023
tx_rejected: 0
tx_overflow: 0
tx_success: 3023
tx_timedout: 0
tx_abort: 0
rx_received: 27865
rx_overflow: 0
rx_errors: 0
num_busoff_err: 0
num_events: 30888
ECR: 0
fdf_rx: 27862
fdf_tx_req: 3016
fdf_tx: 3016
I am testing between a CubeOrange and a Pixhawk6X. I tested 1, 2, 4, 5
and 8 MBit (which are the only valid FD bitrates in our parameters)
Many thanks to Kai from Salient Motion for finding this issue and
providing the corrected timing table
Andrew Tridgell
bugobliterator
Tom Pittenger
Peter Barker