Cantools – an extensive set of CAN bus tools
source link: https://github.com/eerimoq/cantools
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About
CAN BUS tools in Python 3.
- DBC , KCD , SYM, ARXML 4 and CDD file parsing.
- CAN message encoding and decoding.
- Simple and extended signal multiplexing.
- Diagnostic DID encoding and decoding.
-
candump
output decoder. - Node tester .
- C source code generator.
- CAN bus monitor.
Python 2 support is deprecated as Python 3 has better unicode support.
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.database.load_file('tests/files/dbc/motohawk.dbc') >>> db.messages [message('ExampleMessage', 0x1f0, False, 8, 'Example message used as template in MotoHawk models.')] >>> example_message = db.get_message_by_name('ExampleMessage') >>> pprint(example_message.signals) [signal('Enable', 7, 1, 'big_endian', False, 1.0, 0, 0.0, 0.0, '-', False, None, {0: 'Disabled', 1: 'Enabled'}, None), signal('AverageRadius', 6, 6, 'big_endian', False, 0.1, 0, 0.0, 5.0, 'm', False, None, None, ''), signal('Temperature', 0, 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_bus = can.interface.Bus('vcan0', bustype='socketcan') >>> 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 examples for additional examples.
Command line tool
The decode subcommand
Decode CAN frames captured with the Linux program candump
.
$ candump vcan0 | cantools decode tests/files/dbc/motohawk.dbc vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage( Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK ) vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage( Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK ) vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage( Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK )
Alternatively, the decoded message can be printed on a single line:
$ candump vcan0 | cantools decode --single-line tests/files/dbc/motohawk.dbc vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK) vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK) vcan0 1F0 [8] 80 4A 0F 00 00 00 00 00 :: ExampleMessage(Enable: 'Enabled' -, AverageRadius: 0.0 m, Temperature: 255.92 degK)
The dump subcommand
Dump given database in a human readable format:
$ cantools dump tests/files/dbc/motohawk.dbc ================================= Messages ================================= ------------------------------------------------------------------------ Name: ExampleMessage Id: 0x1f0 Length: 8 bytes Cycle time: - ms Senders: PCM1 Layout: Bit 7 6 5 4 3 2 1 0 +---+---+---+---+---+---+---+---+ 0 |<-x|<---------------------x|<--| +---+---+---+---+---+---+---+---+ | +-- AverageRadius +-- Enable +---+---+---+---+---+---+---+---+ 1 |-------------------------------| +---+---+---+---+---+---+---+---+ 2 |----------x| | | | | | B +---+---+---+---+---+---+---+---+ y +-- Temperature t +---+---+---+---+---+---+---+---+ e 3 | | | | | | | | | +---+---+---+---+---+---+---+---+ 4 | | | | | | | | | +---+---+---+---+---+---+---+---+ 5 | | | | | | | | | +---+---+---+---+---+---+---+---+ 6 | | | | | | | | | +---+---+---+---+---+---+---+---+ 7 | | | | | | | | | +---+---+---+---+---+---+---+---+ Signal tree: -- {root} +-- Enable +-- AverageRadius +-- Temperature Signal choices: Enable 0 Disabled 1 Enabled ------------------------------------------------------------------------
The generate C source subcommand
Generate C source code from given database.
The generated code contains:
- Message structs .
- Message pack and unpack functions.
- Signal encode and decode functions.
- Frame id, length, type, cycle time and signal choices defines .
Known limitations:
- The maximum signal size is 64 bits, which in practice is never exceeded.
Below is an example of how to generate C source code from a database. The database is tests/files/dbc/motohawk.dbc
.
$ cantools generate_c_source tests/files/dbc/motohawk.dbc Successfully generated motohawk.h and motohawk.c.
See motohawk.h and motohawk.c for the contents of the generated files.
In the next example we use --database-name
to set a custom namespace for all generated types, defines and functions. The output file names are also changed by this option.
$ cantools generate_c_source --database-name my_database_name tests/files/dbc/motohawk.dbc Successfully generated my_database_name.h and my_database_name.c.
See my_database_name.h and my_database_name.c for the contents of the generated files.
In the last example we use --no-floating-point-numbers
to generate code without floating point types, i.e. float
and double
.
$ cantools generate_c_source --no-floating-point-numbers tests/files/dbc/motohawk.dbc Successfully generated motohawk.h and motohawk.c.
See motohawk_no_floating_point_numbers.h and motohawk_no_floating_point_numbers.c for the contents of the generated files.
Other C code generators:
- http://www.coderdbc.com
- https://github.com/howerj/dbcc
- https://github.com/lonkamikaze/hsk-libs/blob/master/scripts/dbc2c.awk
- https://sourceforge.net/projects/comframe/
The monitor subcommand
Monitor CAN bus traffic in a text based user interface.
$ cantools monitor tests/files/dbc/motohawk.dbc
The menu at the bottom of the monitor shows the available commands.
- Quit: Quit the monitor. Ctrl-C can be used as well.
- Filter: Only display messages matching given regular expression. Press <Enter> to return to the menu from the filter input line.
- Play/Pause: Toggle between playing and paused (or running and freezed).
- Reset: Reset the monitor to its initial state.
Contributing
-
Fork the repository.
-
Install prerequisites.
pip install -r requirements.txt
-
Implement the new feature or bug fix.
-
Implement test case(s) to ensure that future changes do not break legacy.
-
Run the tests.
make test
-
Create a pull request.
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