canlib

Contents

• canlib

  • List connected devices

  • Send and receive single frame

  • Send and receive CAN FD frame

The following sections contain sample code for inspiration on how to use Kvaser Python canlib.

List connected devices

This code print some basic information (device name, EAN number and serial number) from all connected devices.

from canlib import canlib

num_channels = canlib.getNumberOfChannels()
print("Found %d channels" % num_channels)
for ch in range(0, num_channels):
    chdata = canlib.ChannelData(ch)
    print("%d. %s (%s / %s)" % (ch, chdata.device_name,
                                chdata.card_upc_no,
                                chdata.card_serial_no))

Send and receive single frame

Here is some basic code to send and receive a single frame.

from canlib import canlib, Frame
from canlib.canlib import ChannelData

def setUpChannel(channel=0,
                 openFlags=canlib.Open.ACCEPT_VIRTUAL,
                 outputControl=canlib.Driver.NORMAL):
    ch = canlib.openChannel(channel, openFlags)
    print("Using channel: %s, EAN: %s" % (ChannelData(channel).channel_name,
                                          ChannelData(channel).card_upc_no))
    ch.setBusOutputControl(outputControl)
    # Specifying a bus speed of 250 kbit/s. See documentation
    # for more informationon how to set bus parameters.
    params = canlib.busparams.BusParamsTq(
        tq=8,
        phase1=2,
        phase2=2,
        sjw=1,
        prescaler=40,
        prop=3
    )
    ch.set_bus_params_tq(params)
    ch.busOn()
    return ch


def tearDownChannel(ch):
    ch.busOff()
    ch.close()


print("canlib version:", canlib.dllversion())

ch0 = setUpChannel(channel=0)
ch1 = setUpChannel(channel=1)

frame = Frame(
    id_=100,
    data=[1, 2, 3, 4],
    flags=canlib.MessageFlag.EXT
)
ch1.write(frame)

while True:
    try:
        frame = ch0.read()
        print(frame)
        break
    except (canlib.canNoMsg) as ex:
        pass
    except (canlib.canError) as ex:
        print(ex)

tearDownChannel(ch0)
tearDownChannel(ch1)

Send and receive CAN FD frame

Here are some minimal code to send and receive a CAN FD frame.

from canlib import canlib, Frame

# Specifying an arbitration phase bus speed of 1 Mbit/s,
# and a data phase bus speed of 2 Mbit/s. See documentation
# for more information on how to set bus parameters.
params_arbitration = canlib.busparams.BusParamsTq(
    tq=40,
    phase1=8,
    phase2=8,
    sjw=8,
    prescaler=2,
    prop=23
)
params_data = canlib.busparams.BusParamsTq(
    tq=20,
    phase1=15,
    phase2=4,
    sjw=4,
    prescaler=2,
    prop=0
)

# open channel as CAN FD using the flag
ch0 = canlib.openChannel(channel=0, flags=canlib.Open.CAN_FD)
ch0.setBusOutputControl(drivertype=canlib.Driver.NORMAL)
ch0.set_bus_params_tq(params_arbitration, params_data)
ch0.busOn()

ch1 = canlib.openChannel(channel=1, flags=canlib.Open.CAN_FD)
ch1.setBusOutputControl(drivertype=canlib.Driver.NORMAL)
ch1.set_bus_params_tq(params_arbitration, params_data)
ch1.busOn()

# set FDF flag to send using CAN FD
# set BRS flag to send using higher bit rate in the data phase
frame = Frame(
    id_=100,
    data=range(32),
    flags=canlib.MessageFlag.FDF | canlib.MessageFlag.BRS
)
print('Sending', frame)
ch0.write(frame)

frame = ch1.read(timeout=1000)
print('Receiving', frame)

ch0.busOff()
ch1.busOff()