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About

CAN BUS tools.

• DBC and KCD file mangling.
• CAN message encoding and decoding.
• candump output decoder.

Project homepage: https://github.com/eerimoq/cantools

Documentation: http://cantools.readthedocs.org/en/latest

Installation

pip install cantools

Example usage

Scripting

The example starts by parsing a small DBC-file and printing its messages and signals.

>>> import cantools
>>> from pprint import pprint
>>> db = cantools.db.load_file('tests/files/motohawk.dbc')
>>> db.messages
[message('ExampleMessage', 0x1f0, 8, 'Example message used as template in MotoHawk models.')]
>>> example_message = db.messages[0]
>>> pprint(example_message.signals)
[signal('Enable', 0, 1, 'big_endian', False, 1.0, 0, 0.0, 0.0, '-', False, None, {0: 'Disabled', 1: 'Enabled'}, None),
 signal('AverageRadius', 1, 6, 'big_endian', False, 0.1, 0, 0.0, 5.0, 'm', False, None, None, ''),
 signal('Temperature', 7, 12, 'big_endian', True, 0.01, 250, 229.53, 270.47, 'degK', False, None, None, None)]

The example continues encoding a message and sending it on a CAN bus using the python-can package.

>>> import can
>>> can.rc['interface'] = 'socketcan_ctypes'
>>> can.rc['channel'] = 'vcan0'
>>> can_bus = can.interface.Bus()
>>> data = example_message.encode({'Temperature': 250.1, 'AverageRadius': 3.2, 'Enable': 1})
>>> message = can.Message(arbitration_id=example_message.frame_id, data=data)
>>> can_bus.send(message)

Alternatively, a message can be encoded using the encode_message() method on the database object.

The last part of the example receives and decodes a CAN message.

>>> message = can_bus.recv()
>>> db.decode_message(message.arbitration_id, message.data)
{'AverageRadius': 3.2, 'Enable': 'Enabled', 'Temperature': 250.09}

See the test suite for additional examples: https://github.com/eerimoq/cantools/blob/master/tests/test_cantools.py

Command line tool

Decode CAN frames captured with the Linux program candump.

$ candump vcan0 | cantools decode motohawk.dbc
  vcan0  1F0   [7]  80 4A 0F 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK)
  vcan0  1F0   [7]  80 4A 0F 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK)
  vcan0  1F0   [7]  80 4A 0F 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK)

Contributing

1. Fork the repository.
2. Implement the new feature or bug fix.
3. Implement test case(s) to ensure that future changes do not break legacy.

4. Run the tests.

   make test

5. Create a pull request.