Unable to send CAN FD frame using python-can (PCAN-USB Pro FD)

[samuraii95]

Hi everyone, I’m currently working on a test bench that communicates over CAN and CAN FD using a PCAN-USB Pro FD interface.

Sending standard CAN messages like 0x214 works perfectly from both Python and PCAN-View 👍

But I can't seem to send a CAN FD frame properly through Python. My goal is to send a frame with ID 0x1E38400C, data length = 2, and data = [0xEB, 0x10], using CAN FD (with is_fd=True, bitrate_switch=True, is_extended_id=True) 👎

I can send this same frame via PCAN-View successfully when enabling FD mode. So I know the hardware and channel config are okay. I’ve tried a few code samples including the official ones from the python-can documentation, but I either get:

• No error, but the frame is sent as standard CAN (not FD), or

• can.CanError: A parameter contains an invalid value

Configuration:

• Interface: pcan
• Channel: PCAN_USBBUS2
• Bitrate: 500000
• Data bitrate: 2000000 (Can FD = 2Mb/s) ?

My setup:

OS and version: window11 PCAN-USB Pro FD Python version: 3.12.9 python-can version: 4.50.0 VScode : 1.100.2 notepad++: 8.8.1

my functions

def periodic_message_can2(can_id=0x1E38400C, interface='pcan', channel='PCAN_USBBUS2'):
 
    try:
        bus = can.interface.Bus(interface=interface, channel=channel, fd=True, bitrate=500000, data_bitrate=2000000)
        can_data_on = [0xEB, 0x10]
 
        msg = can.Message(
            arbitration_id=can_id,
            data=can_data_on,
            is_extended_id=True,
            is_fd=True,
            bitrate_switch=True,  
            dlc=2
        )
        bus.send_periodic(msg, 1.0)
        print(" Message FD envoyé en périodique.")
 
    except can.CanError as e:
        print(f" Erreur CAN : {e}")
 
    except Exception as e:
        print(f" Erreur générale : {e}")
#OUTPUT for this one : can.CanError: A parameter contains an invalid value
############################################################
#Second function
def periodic_message_can(can_id=0x1E38400C, interface='pcan', channel='PCAN_USBBUS2'):
 
    try:
 
        bus = can.interface.Bus(interface=interface, channel=channel, fd=True)
 
        can_data_on = [0xEB, 0x10]
 
 
        msg = can.Message(arbitration_id=can_id, data=can_data_on, is_extended_id=True, is_fd=True, dlc=2, is_rx=False)
 
        bus.send_periodic(msg, 1)
 
    except can.CanError as e:
 
        print(f"Erreur CAN : {e}")
 
    except Exception as e:
 
        print(f"Erreur générale : {e}")

#The function executes without any errors, but it looks like my frame is not sent as CAN FD...

When I check this frame in PCAN-View, the “Type” field is empty, which usually indicates it's a standard CAN frame and not an FD one. So even though I set is_fd=True in the code, it seems like it's not actually taking effect.

[zariiii9003]

You need to set all bit timing parameters (nom_, data_) or use the BitTimingFd class.