Source code for can.interfaces.pcan.pcan

Enable basic CAN over a PCAN USB device.
import logging
import time
from datetime import datetime
import platform
from typing import Optional, List, Tuple, Union, Any

from packaging import version

from can import (
from can.util import check_or_adjust_timing_clock, dlc2len, len2dlc
from .basic import (

# Set up logging
log = logging.getLogger("can.pcan")

MIN_PCAN_API_VERSION = version.parse("4.2.0")

    # use the "uptime" library if available
    import uptime

    # boottime() and fromtimestamp() are timezone offset, so the difference is not.
    if uptime.boottime() is None:
        boottimeEpoch = 0
        boottimeEpoch = (uptime.boottime() - datetime.fromtimestamp(0)).total_seconds()
except ImportError as error:
        "uptime library not available, timestamps are relative to boot time and not to Epoch UTC",
    boottimeEpoch = 0


        # Try builtin Python 3 Windows API
        from _overlapped import CreateEvent
        from _winapi import WaitForSingleObject, WAIT_OBJECT_0, INFINITE

        HAS_EVENTS = True
    except ImportError:

elif IS_LINUX:
        import errno
        import os
        import select

        HAS_EVENTS = True
    except Exception:

[docs]class PcanBus(BusABC): def __init__( self, channel: str = "PCAN_USBBUS1", device_id: Optional[int] = None, state: BusState = BusState.ACTIVE, timing: Optional[Union[BitTiming, BitTimingFd]] = None, bitrate: int = 500000, **kwargs: Any, ): """A PCAN USB interface to CAN. On top of the usual :class:`~can.Bus` methods provided, the PCAN interface includes the :meth:`flash` and :meth:`status` methods. :param str channel: The can interface name. An example would be 'PCAN_USBBUS1'. Alternatively the value can be an int with the numerical value. Default is 'PCAN_USBBUS1' :param int device_id: Select the PCAN interface based on its ID. The device ID is a 8/32bit value that can be configured for each PCAN device. If you set the device_id parameter, it takes precedence over the channel parameter. The constructor searches all connected interfaces and initializes the first one that matches the parameter value. If no device is found, an exception is raised. :param can.bus.BusState state: BusState of the channel. Default is ACTIVE :param timing: An instance of :class:`~can.BitTiming` or :class:`~can.BitTimingFd` to specify the bit timing parameters for the PCAN interface. If this parameter is provided, it takes precedence over all other timing-related parameters. If this parameter is not provided, the bit timing parameters can be specified using the `bitrate` parameter for standard CAN or the `fd`, `f_clock`, `f_clock_mhz`, `nom_brp`, `nom_tseg1`, `nom_tseg2`, `nom_sjw`, `data_brp`, `data_tseg1`, `data_tseg2`, and `data_sjw` parameters for CAN FD. Note that the `f_clock` value of the `timing` instance must be 8_000_000 for standard CAN or any of the following values for CAN FD: 20_000_000, 24_000_000, 30_000_000, 40_000_000, 60_000_000, 80_000_000. :param int bitrate: Bitrate of channel in bit/s. Default is 500 kbit/s. Ignored if using CanFD. :param bool fd: Should the Bus be initialized in CAN-FD mode. :param int f_clock: Clock rate in Hz. Any of the following: 20000000, 24000000, 30000000, 40000000, 60000000, 80000000. Ignored if not using CAN-FD. Pass either f_clock or f_clock_mhz. :param int f_clock_mhz: Clock rate in MHz. Any of the following: 20, 24, 30, 40, 60, 80. Ignored if not using CAN-FD. Pass either f_clock or f_clock_mhz. :param int nom_brp: Clock prescaler for nominal time quantum. In the range (1..1024) Ignored if not using CAN-FD. :param int nom_tseg1: Time segment 1 for nominal bit rate, that is, the number of quanta from (but not including) the Sync Segment to the sampling point. In the range (1..256). Ignored if not using CAN-FD. :param int nom_tseg2: Time segment 2 for nominal bit rate, that is, the number of quanta from the sampling point to the end of the bit. In the range (1..128). Ignored if not using CAN-FD. :param int nom_sjw: Synchronization Jump Width for nominal bit rate. Decides the maximum number of time quanta that the controller can resynchronize every bit. In the range (1..128). Ignored if not using CAN-FD. :param int data_brp: Clock prescaler for fast data time quantum. In the range (1..1024) Ignored if not using CAN-FD. :param int data_tseg1: Time segment 1 for fast data bit rate, that is, the number of quanta from (but not including) the Sync Segment to the sampling point. In the range (1..32). Ignored if not using CAN-FD. :param int data_tseg2: Time segment 2 for fast data bit rate, that is, the number of quanta from the sampling point to the end of the bit. In the range (1..16). Ignored if not using CAN-FD. :param int data_sjw: Synchronization Jump Width for fast data bit rate. Decides the maximum number of time quanta that the controller can resynchronize every bit. In the range (1..16). Ignored if not using CAN-FD. :param bool auto_reset: Enable automatic recovery in bus off scenario. Resetting the driver takes ~500ms during which it will not be responsive. """ self.m_objPCANBasic = PCANBasic() if device_id is not None: channel = self._find_channel_by_dev_id(device_id) if channel is None: err_msg = f"Cannot find a channel with ID {device_id:08x}" raise ValueError(err_msg) self.channel_info = str(channel) self.fd = isinstance(timing, BitTimingFd) if timing else kwargs.get("fd", False) hwtype = PCAN_TYPE_ISA ioport = 0x02A0 interrupt = 11 if not isinstance(channel, int): channel = PCAN_CHANNEL_NAMES[channel] self.m_PcanHandle = channel self.check_api_version() if state in [BusState.ACTIVE, BusState.PASSIVE]: self.state = state else: raise ValueError("BusState must be Active or Passive") if isinstance(timing, BitTiming): timing = check_or_adjust_timing_clock(timing, VALID_PCAN_CAN_CLOCKS) pcan_bitrate = TPCANBaudrate(timing.btr0 << 8 | timing.btr1) result = self.m_objPCANBasic.Initialize( self.m_PcanHandle, pcan_bitrate, hwtype, ioport, interrupt ) elif self.fd: if isinstance(timing, BitTimingFd): timing = check_or_adjust_timing_clock( timing, sorted(VALID_PCAN_FD_CLOCKS, reverse=True) ) # We dump the timing parameters into the kwargs because they have equal names # as the kwargs parameters and this saves us one additional code path kwargs.update(timing) clock_param = "f_clock" if "f_clock" in kwargs else "f_clock_mhz" fd_parameters_values = [ f"{key}={kwargs[key]}" for key in (clock_param,) + PCAN_FD_PARAMETER_LIST if key in kwargs ] self.fd_bitrate = ", ".join(fd_parameters_values).encode("ascii") result = self.m_objPCANBasic.InitializeFD( self.m_PcanHandle, self.fd_bitrate ) else: pcan_bitrate = PCAN_BITRATES.get(bitrate, PCAN_BAUD_500K) result = self.m_objPCANBasic.Initialize( self.m_PcanHandle, pcan_bitrate, hwtype, ioport, interrupt ) if result != PCAN_ERROR_OK: raise PcanCanInitializationError(self._get_formatted_error(result)) result = self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_ALLOW_ERROR_FRAMES, PCAN_PARAMETER_ON ) if result != PCAN_ERROR_OK: if platform.system() != "Darwin": raise PcanCanInitializationError(self._get_formatted_error(result)) else: # TODO Remove Filter when MACCan actually supports it: # log.debug( "Ignoring error. PCAN_ALLOW_ERROR_FRAMES is still unsupported by OSX Library PCANUSB v0.11.2" ) if kwargs.get("auto_reset", False): result = self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_BUSOFF_AUTORESET, PCAN_PARAMETER_ON ) if result != PCAN_ERROR_OK: raise PcanCanInitializationError(self._get_formatted_error(result)) if HAS_EVENTS: if IS_WINDOWS: self._recv_event = CreateEvent(None, 0, 0, None) result = self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_RECEIVE_EVENT, self._recv_event ) elif IS_LINUX: result, self._recv_event = self.m_objPCANBasic.GetValue( self.m_PcanHandle, PCAN_RECEIVE_EVENT ) if result != PCAN_ERROR_OK: raise PcanCanInitializationError(self._get_formatted_error(result)) super().__init__(channel=channel, state=state, bitrate=bitrate, **kwargs) def _find_channel_by_dev_id(self, device_id): """ Iterate over all possible channels to find a channel that matches the device ID. This method is somewhat brute force, but the Basic API only offers a suitable API call since V4.4.0. :param device_id: The device_id for which to search for :return: The name of a PCAN channel that matches the device ID, or None if no channel can be found. """ for ch_name, ch_handle in PCAN_CHANNEL_NAMES.items(): err, cur_dev_id = self.m_objPCANBasic.GetValue( ch_handle, PCAN_DEVICE_NUMBER ) if err != PCAN_ERROR_OK: continue if cur_dev_id == device_id: return ch_name return None def _get_formatted_error(self, error): """ Gets the text using the GetErrorText API function. If the function call succeeds, the translated error is returned. If it fails, a text describing the current error is returned. Multiple errors may be present in which case their individual messages are included in the return string, one line per error. """ def bits(n): """ Iterate over all the set bits in `n`, returning the masked bits at the set indices """ while n: # Create a mask to mask the lowest set bit in n mask = ~n + 1 masked_value = n & mask yield masked_value # Toggle the lowest set bit n ^= masked_value stsReturn = self.m_objPCANBasic.GetErrorText(error, 0x9) if stsReturn[0] != PCAN_ERROR_OK: strings = [] for b in bits(error): stsReturn = self.m_objPCANBasic.GetErrorText(b, 0x9) if stsReturn[0] != PCAN_ERROR_OK: text = "An error occurred. Error-code's text ({:X}h) couldn't be retrieved".format( error ) else: text = stsReturn[1].decode("utf-8", errors="replace") strings.append(text) complete_text = "\n".join(strings) else: complete_text = stsReturn[1].decode("utf-8", errors="replace") return complete_text def get_api_version(self): error, value = self.m_objPCANBasic.GetValue(PCAN_NONEBUS, PCAN_API_VERSION) if error != PCAN_ERROR_OK: raise CanInitializationError(f"Failed to read pcan basic api version") return version.parse(value.decode("ascii")) def check_api_version(self): apv = self.get_api_version() if apv < MIN_PCAN_API_VERSION: log.warning( f"Minimum version of pcan api is {MIN_PCAN_API_VERSION}." f" Installed version is {apv}. Consider upgrade of pcan basic package" )
[docs] def status(self): """ Query the PCAN bus status. :rtype: int :return: The status code. See values in **basic.PCAN_ERROR_** """ return self.m_objPCANBasic.GetStatus(self.m_PcanHandle)
[docs] def status_is_ok(self): """ Convenience method to check that the bus status is OK """ status = self.status() return status == PCAN_ERROR_OK
[docs] def reset(self): """ Command the PCAN driver to reset the bus after an error. """ status = self.m_objPCANBasic.Reset(self.m_PcanHandle) return status == PCAN_ERROR_OK
[docs] def get_device_number(self): """ Return the PCAN device number. :rtype: int :return: PCAN device number """ error, value = self.m_objPCANBasic.GetValue( self.m_PcanHandle, PCAN_DEVICE_NUMBER ) if error != PCAN_ERROR_OK: return None return value
[docs] def set_device_number(self, device_number): """ Set the PCAN device number. :param device_number: new PCAN device number :rtype: bool :return: True if device number set successfully """ try: if ( self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_DEVICE_NUMBER, int(device_number) ) != PCAN_ERROR_OK ): raise ValueError() except ValueError: log.error("Invalid value '%s' for device number.", device_number) return False return True
def _recv_internal( self, timeout: Optional[float] ) -> Tuple[Optional[Message], bool]: end_time = time.time() + timeout if timeout is not None else None while True: if self.fd: result, pcan_msg, pcan_timestamp = self.m_objPCANBasic.ReadFD( self.m_PcanHandle ) else: result, pcan_msg, pcan_timestamp = self.m_objPCANBasic.Read( self.m_PcanHandle ) if result == PCAN_ERROR_OK: # message received break if result == PCAN_ERROR_QRCVEMPTY: # receive queue is empty, wait or return on timeout if end_time is None: time_left: Optional[float] = None timed_out = False else: time_left = max(0.0, end_time - time.time()) timed_out = time_left == 0.0 if timed_out: return None, False if not HAS_EVENTS: # polling mode time.sleep(0.001) continue if IS_WINDOWS: # Windows with event if time_left is None: time_left_ms = INFINITE else: time_left_ms = int(time_left * 1000) _ret = WaitForSingleObject(self._recv_event, time_left_ms) if _ret == WAIT_OBJECT_0: continue elif IS_LINUX: # Linux with event recv, _, _ =[self._recv_event], [], [], time_left) if self._recv_event in recv: continue elif result & (PCAN_ERROR_BUSLIGHT | PCAN_ERROR_BUSHEAVY): log.warning(self._get_formatted_error(result)) else: raise PcanCanOperationError(self._get_formatted_error(result)) return None, False is_extended_id = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_EXTENDED.value) is_remote_frame = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_RTR.value) is_fd = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_FD.value) bitrate_switch = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_BRS.value) error_state_indicator = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_ESI.value) is_error_frame = bool(pcan_msg.MSGTYPE & PCAN_MESSAGE_ERRFRAME.value) if self.fd: dlc = dlc2len(pcan_msg.DLC) timestamp = boottimeEpoch + (pcan_timestamp.value / (1000.0 * 1000.0)) else: dlc = pcan_msg.LEN timestamp = boottimeEpoch + ( ( pcan_timestamp.micros + 1000 * pcan_timestamp.millis + 0x100000000 * 1000 * pcan_timestamp.millis_overflow ) / (1000.0 * 1000.0) ) rx_msg = Message( timestamp=timestamp, arbitration_id=pcan_msg.ID, is_extended_id=is_extended_id, is_remote_frame=is_remote_frame, is_error_frame=is_error_frame, dlc=dlc, data=pcan_msg.DATA[:dlc], is_fd=is_fd, bitrate_switch=bitrate_switch, error_state_indicator=error_state_indicator, ) return rx_msg, False
[docs] def send(self, msg, timeout=None): msgType = ( PCAN_MESSAGE_EXTENDED.value if msg.is_extended_id else PCAN_MESSAGE_STANDARD.value ) if msg.is_remote_frame: msgType |= PCAN_MESSAGE_RTR.value if msg.is_error_frame: msgType |= PCAN_MESSAGE_ERRFRAME.value if msg.is_fd: msgType |= PCAN_MESSAGE_FD.value if msg.bitrate_switch: msgType |= PCAN_MESSAGE_BRS.value if msg.error_state_indicator: msgType |= PCAN_MESSAGE_ESI.value if self.fd: # create a TPCANMsg message structure CANMsg = TPCANMsgFD() # configure the message. ID, Length of data, message type and data CANMsg.ID = msg.arbitration_id CANMsg.DLC = len2dlc(msg.dlc) CANMsg.MSGTYPE = msgType # copy data for i in range(msg.dlc): CANMsg.DATA[i] =[i] log.debug("Data: %s", log.debug("Type: %s", type( result = self.m_objPCANBasic.WriteFD(self.m_PcanHandle, CANMsg) else: # create a TPCANMsg message structure CANMsg = TPCANMsg() # configure the message. ID, Length of data, message type and data CANMsg.ID = msg.arbitration_id CANMsg.LEN = msg.dlc CANMsg.MSGTYPE = msgType # if a remote frame will be sent, data bytes are not important. if not msg.is_remote_frame: # copy data for i in range(CANMsg.LEN): CANMsg.DATA[i] =[i] log.debug("Data: %s", log.debug("Type: %s", type( result = self.m_objPCANBasic.Write(self.m_PcanHandle, CANMsg) if result != PCAN_ERROR_OK: raise PcanCanOperationError( "Failed to send: " + self._get_formatted_error(result) )
[docs] def flash(self, flash): """ Turn on or off flashing of the device's LED for physical identification purposes. """ self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_CHANNEL_IDENTIFYING, bool(flash) )
[docs] def shutdown(self): super().shutdown() if HAS_EVENTS and IS_LINUX: self.m_objPCANBasic.SetValue(self.m_PcanHandle, PCAN_RECEIVE_EVENT, 0) self.m_objPCANBasic.Uninitialize(self.m_PcanHandle)
@property def state(self): return self._state @state.setter def state(self, new_state): # declare here, which is called by __init__() self._state = new_state # pylint: disable=attribute-defined-outside-init if new_state is BusState.ACTIVE: self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_LISTEN_ONLY, PCAN_PARAMETER_OFF ) elif new_state is BusState.PASSIVE: # When this mode is set, the CAN controller does not take part on active events (eg. transmit CAN messages) # but stays in a passive mode (CAN monitor), in which it can analyse the traffic on the CAN bus used by a # PCAN channel. See also the Philips Data Sheet "SJA1000 Stand-alone CAN controller". self.m_objPCANBasic.SetValue( self.m_PcanHandle, PCAN_LISTEN_ONLY, PCAN_PARAMETER_ON ) @staticmethod def _detect_available_configs(): channels = [] try: library_handle = PCANBasic() except OSError: return channels interfaces = [] if platform.system() != "Darwin": res, value = library_handle.GetValue(PCAN_NONEBUS, PCAN_ATTACHED_CHANNELS) if res != PCAN_ERROR_OK: return interfaces channel_information: List[TPCANChannelInformation] = list(value) for channel in channel_information: # find channel name in PCAN_CHANNEL_NAMES by value channel_name = next( _channel_name for _channel_name, channel_id in PCAN_CHANNEL_NAMES.items() if channel_id.value == channel.channel_handle ) channel_config = { "interface": "pcan", "channel": channel_name, "supports_fd": bool(channel.device_features & FEATURE_FD_CAPABLE), "controller_number": channel.controller_number, "device_features": channel.device_features, "device_id": channel.device_id, "device_name": channel.device_name.decode("latin-1"), "device_type": channel.device_type, "channel_condition": channel.channel_condition, } interfaces.append(channel_config) return interfaces for i in range(16): interfaces.append( { "id": TPCANHandle(PCAN_PCIBUS1.value + i), "name": "PCAN_PCIBUS" + str(i + 1), } ) for i in range(16): interfaces.append( { "id": TPCANHandle(PCAN_USBBUS1.value + i), "name": "PCAN_USBBUS" + str(i + 1), } ) for i in range(2): interfaces.append( { "id": TPCANHandle(PCAN_PCCBUS1.value + i), "name": "PCAN_PCCBUS" + str(i + 1), } ) for i in range(16): interfaces.append( { "id": TPCANHandle(PCAN_LANBUS1.value + i), "name": "PCAN_LANBUS" + str(i + 1), } ) for i in interfaces: try: error, value = library_handle.GetValue(i["id"], PCAN_CHANNEL_CONDITION) if error != PCAN_ERROR_OK or value != PCAN_CHANNEL_AVAILABLE: continue has_fd = False error, value = library_handle.GetValue(i["id"], PCAN_CHANNEL_FEATURES) if error == PCAN_ERROR_OK: has_fd = bool(value & FEATURE_FD_CAPABLE) channels.append( {"interface": "pcan", "channel": i["name"], "supports_fd": has_fd} ) except AttributeError: # Ignore if this fails for some interfaces pass return channels
[docs] def status_string(self) -> Optional[str]: """ Query the PCAN bus status. :return: The status description, if any was found. """ try: return PCAN_DICT_STATUS[self.status()] except KeyError: return None
class PcanError(CanError): """A generic error on a PCAN bus.""" class PcanCanOperationError(CanOperationError, PcanError): """Like :class:`can.exceptions.CanOperationError`, but specific to Pcan.""" class PcanCanInitializationError(CanInitializationError, PcanError): """Like :class:`can.exceptions.CanInitializationError`, but specific to Pcan."""