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mgiacofelixdivo
mgiaco
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felixdivo
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Add a possibility to use LISTEN ONLY for the CAN Hardware. (hardbyte#235)
* add interface example definition for beginners * add a state for the bus to handle active and passive mode, currently only implemented for pcan * decode the right way * use ACTIVE state as default for getter, raise NotImplementedError on base setter
1 parent ddfac97 commit 64e8e66

4 files changed

Lines changed: 88 additions & 3 deletions

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‎can/bus.py‎

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Original file line numberDiff line numberDiff line change
@@ -10,12 +10,16 @@
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from abc import ABCMeta, abstractmethod
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import logging
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import threading
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from collections import namedtuple
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from can.broadcastmanager import ThreadBasedCyclicSendTask
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logger = logging.getLogger(__name__)
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BusState = namedtuple('BusState', 'ACTIVE, PASSIVE, ERROR')
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class BusABC(object):
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"""CAN Bus Abstract Base Class
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@@ -151,6 +155,23 @@ def shutdown(self):
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"""
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self.flush_tx_buffer()
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@property
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def state(self):
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"""
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Return the current state of the hardware
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:return: ACTIVE, PASSIVE or ERROR
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:rtype: NamedTuple
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"""
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return BusState.ACTIVE
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@state.setter
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def state(self, new_state):
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"""
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Set the new state of the hardware
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:param new_state: BusState.ACTIVE, BusState.PASSIVE or BusState.ERROR
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"""
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raise NotImplementedError("Property is not implemented.")
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@staticmethod
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def _detect_available_configs():
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"""Detect all configurations/channels that this interface could

‎can/interfaces/pcan/pcan.py‎

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Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
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import can
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from can import CanError
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from can.bus import BusABC
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from can.bus import BusABC, BusState
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from can.message import Message
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from can.interfaces.pcan.PCANBasic import *
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@@ -67,7 +67,7 @@
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class PcanBus(BusABC):
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def __init__(self, channel, *args, **kwargs):
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def __init__(self, channel, state=BusState.ACTIVE, *args, **kwargs):
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"""A PCAN USB interface to CAN.
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On top of the usual :class:`~can.Bus` methods provided,
@@ -76,10 +76,13 @@ def __init__(self, channel, *args, **kwargs):
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:param str channel:
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The can interface name. An example would be PCAN_USBBUS1
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:param BusState state:
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BusState of the channel.
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Default is ACTIVE
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:param int bitrate:
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Bitrate of channel in bit/s.
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Default is 500 Kbs
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"""
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if channel is None or channel == '':
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raise ArgumentError("Must specify a PCAN channel")
@@ -96,6 +99,11 @@ def __init__(self, channel, *args, **kwargs):
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self.m_objPCANBasic = PCANBasic()
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self.m_PcanHandle = globals()[channel]
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if state is BusState.ACTIVE or BusState.PASSIVE:
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self._state = state
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else:
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raise ArgumentError("BusState must be Active or Passive")
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result = self.m_objPCANBasic.Initialize(self.m_PcanHandle, pcan_bitrate, hwtype, ioport, interrupt)
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if result != PCAN_ERROR_OK:
@@ -262,6 +270,24 @@ def flash(self, flash):
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def shutdown(self):
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self.m_objPCANBasic.Uninitialize(self.m_PcanHandle)
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@property
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def state(self):
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return self._state
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@state.setter
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def state(self, new_state):
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self._state = new_state
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if new_state is BusState.ACTIVE:
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self.m_objPCANBasic.SetValue(self.m_PcanHandle, PCAN_LISTEN_ONLY, PCAN_PARAMETER_OFF)
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if new_state is BusState.PASSIVE:
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# When this mode is set, the CAN controller does not take part on active events (eg. transmit CAN messages)
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# but stays in a passive mode (CAN monitor), in which it can analyse the traffic on the CAN bus used by a
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# PCAN channel. See also the Philips Data Sheet "SJA1000 Stand-alone CAN controller".
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self.m_objPCANBasic.SetValue(self.m_PcanHandle, PCAN_LISTEN_ONLY, PCAN_PARAMETER_ON)
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class PcanError(CanError):
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pass

‎can/logger.py‎

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@@ -24,6 +24,7 @@
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import socket
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import can
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from can.bus import BusState
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from can.io.logger import Logger
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@@ -57,6 +58,10 @@ def main():
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parser.add_argument('-b', '--bitrate', type=int,
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help='''Bitrate to use for the CAN bus.''')
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group = parser.add_mutually_exclusive_group(required=False)
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group.add_argument('--active', action='store_true')
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group.add_argument('--passive', action='store_true')
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results = parser.parse_args()
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verbosity = results.verbosity
@@ -83,6 +88,13 @@ def main():
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if results.bitrate:
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config["bitrate"] = results.bitrate
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bus = can.interface.Bus(results.channel, **config)
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if results.active:
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bus.state = BusState.ACTIVE
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if results.passive:
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bus.state = BusState.PASSIVE
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print('Connected to {}: {}'.format(bus.__class__.__name__, bus.channel_info))
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print('Can Logger (Started on {})\n'.format(datetime.datetime.now()))
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logger = Logger(results.log_file)

‎examples/receive_all.py‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,26 @@
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from __future__ import print_function
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import can
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from can.bus import BusState
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def receive_all():
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bus = can.interface.Bus(bustype='pcan', channel='PCAN_USBBUS1', bitrate=250000)
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#bus = can.interface.Bus(bustype='ixxat', channel=0, bitrate=250000)
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#bus = can.interface.Bus(bustype='vector', app_name='CANalyzer', channel=0, bitrate=250000)
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bus.state = BusState.ACTIVE
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#bus.state = BusState.PASSIVE
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try:
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while True:
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msg = bus.recv(1)
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if msg is not None:
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print(msg)
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except KeyboardInterrupt:
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pass
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if __name__ == "__main__":
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receive_all()

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