Source code for can.interfaces.ixxat.canlib_vcinpl2

"""
Ctypes wrapper module for IXXAT Virtual CAN Interface V3 on win32 systems

TODO: We could implement this interface such that setting other filters
      could work when the initial filters were set to zero using the
      software fallback. Or could the software filters even be changed
      after the connection was opened? We need to document that bahaviour!
      See also the NICAN interface.

"""

import ctypes
import functools
import logging
import sys
from typing import Optional, Callable, Tuple

from can import BusABC, Message
from can.exceptions import CanInterfaceNotImplementedError, CanInitializationError
from can.broadcastmanager import (
    LimitedDurationCyclicSendTaskABC,
    RestartableCyclicTaskABC,
)
from can.ctypesutil import CLibrary, HANDLE, PHANDLE, HRESULT as ctypes_HRESULT

import can.util
from can.util import deprecated_args_alias

from . import constants, structures
from .exceptions import *

__all__ = [
    "VCITimeout",
    "VCIError",
    "VCIBusOffError",
    "VCIDeviceNotFoundError",
    "IXXATBus",
    "vciFormatError",
]

log = logging.getLogger("can.ixxat")

from time import perf_counter

# Hack to have vciFormatError as a free function, see below
vciFormatError = None

# main ctypes instance
_canlib = None
# TODO: Use ECI driver for linux
if sys.platform == "win32" or sys.platform == "cygwin":
    try:
        _canlib = CLibrary("vcinpl2.dll")
    except Exception as e:
        log.warning("Cannot load IXXAT vcinpl library: %s", e)
else:
    # Will not work on other systems, but have it importable anyway for
    # tests/sphinx
    log.warning("IXXAT VCI library does not work on %s platform", sys.platform)


def __vciFormatErrorExtended(
    library_instance: CLibrary, function: Callable, vret: int, args: Tuple
):
    """Format a VCI error and attach failed function, decoded HRESULT and arguments
    :param CLibrary library_instance:
        Mapped instance of IXXAT vcinpl library
    :param callable function:
        Failed function
    :param HRESULT vret:
        HRESULT returned by vcinpl call
    :param args:
        Arbitrary arguments tuple
    :return:
        Formatted string
    """
    # TODO: make sure we don't generate another exception
    return "{} - arguments were {}".format(
        __vciFormatError(library_instance, function, vret), args
    )


def __vciFormatError(library_instance: CLibrary, function: Callable, vret: int):
    """Format a VCI error and attach failed function and decoded HRESULT
    :param CLibrary library_instance:
        Mapped instance of IXXAT vcinpl library
    :param callable function:
        Failed function
    :param HRESULT vret:
        HRESULT returned by vcinpl call
    :return:
        Formatted string
    """
    buf = ctypes.create_string_buffer(constants.VCI_MAX_ERRSTRLEN)
    ctypes.memset(buf, 0, constants.VCI_MAX_ERRSTRLEN)
    library_instance.vciFormatError(vret, buf, constants.VCI_MAX_ERRSTRLEN)
    return "function {} failed ({})".format(
        function._name, buf.value.decode("utf-8", "replace")
    )


def __check_status(result, function, args):
    """
    Check the result of a vcinpl function call and raise appropriate exception
    in case of an error. Used as errcheck function when mapping C functions
    with ctypes.
        :param result:
            Function call numeric result
        :param callable function:
            Called function
        :param args:
            Arbitrary arguments tuple
        :raise:
            :class:VCITimeout
            :class:VCIRxQueueEmptyError
            :class:StopIteration
            :class:VCIError
    """
    if result == constants.VCI_E_TIMEOUT:
        raise VCITimeout(f"Function {function._name} timed out")
    elif result == constants.VCI_E_RXQUEUE_EMPTY:
        raise VCIRxQueueEmptyError()
    elif result == constants.VCI_E_NO_MORE_ITEMS:
        raise StopIteration()
    elif result == constants.VCI_E_ACCESSDENIED:
        pass  # not a real error, might happen if another program has initialized the bus
    elif result != constants.VCI_OK:
        raise VCIError(vciFormatError(function, result))

    return result


try:
    hresult_type = ctypes.c_ulong
    # Map all required symbols and initialize library ---------------------------
    # HRESULT VCIAPI vciInitialize ( void );
    _canlib.map_symbol("vciInitialize", hresult_type, (), __check_status)

    # void VCIAPI vciFormatError (HRESULT hrError, PCHAR pszText, UINT32 dwsize);
    try:
        _canlib.map_symbol(
            "vciFormatError", None, (ctypes_HRESULT, ctypes.c_char_p, ctypes.c_uint32)
        )
    except:
        _canlib.map_symbol(
            "vciFormatErrorA", None, (ctypes_HRESULT, ctypes.c_char_p, ctypes.c_uint32)
        )
        _canlib.vciFormatError = _canlib.vciFormatErrorA
    # Hack to have vciFormatError as a free function
    vciFormatError = functools.partial(__vciFormatError, _canlib)

    # HRESULT VCIAPI vciEnumDeviceOpen( OUT PHANDLE hEnum );
    _canlib.map_symbol("vciEnumDeviceOpen", hresult_type, (PHANDLE,), __check_status)
    # HRESULT VCIAPI vciEnumDeviceClose ( IN HANDLE hEnum );
    _canlib.map_symbol("vciEnumDeviceClose", hresult_type, (HANDLE,), __check_status)
    # HRESULT VCIAPI vciEnumDeviceNext( IN  HANDLE hEnum, OUT PVCIDEVICEINFO pInfo );
    _canlib.map_symbol(
        "vciEnumDeviceNext",
        hresult_type,
        (HANDLE, structures.PVCIDEVICEINFO),
        __check_status,
    )

    # HRESULT VCIAPI vciDeviceOpen( IN  REFVCIID rVciid, OUT PHANDLE  phDevice );
    _canlib.map_symbol(
        "vciDeviceOpen", hresult_type, (structures.PVCIID, PHANDLE), __check_status
    )
    # HRESULT vciDeviceClose( HANDLE hDevice )
    _canlib.map_symbol("vciDeviceClose", hresult_type, (HANDLE,), __check_status)

    # HRESULT VCIAPI canChannelOpen( IN  HANDLE  hDevice, IN  UINT32  dwCanNo, IN  BOOL    fExclusive, OUT PHANDLE phCanChn );
    _canlib.map_symbol(
        "canChannelOpen",
        hresult_type,
        (HANDLE, ctypes.c_uint32, ctypes.c_long, PHANDLE),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI
    #   canChannelInitialize( IN HANDLE hCanChn,
    #                         IN UINT16 wRxFifoSize,
    #                         IN UINT16 wRxThreshold,
    #                         IN UINT16 wTxFifoSize,
    #                         IN UINT16 wTxThreshold,
    #                         IN UINT32 dwFilterSize,
    #                         IN UINT8  bFilterMode );
    _canlib.map_symbol(
        "canChannelInitialize",
        hresult_type,
        (
            HANDLE,
            ctypes.c_uint16,
            ctypes.c_uint16,
            ctypes.c_uint16,
            ctypes.c_uint16,
            ctypes.c_uint32,
            ctypes.c_uint8,
        ),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI canChannelActivate( IN HANDLE hCanChn, IN BOOL   fEnable );
    _canlib.map_symbol(
        "canChannelActivate", hresult_type, (HANDLE, ctypes.c_long), __check_status
    )
    # HRESULT canChannelClose( HANDLE hChannel )
    _canlib.map_symbol("canChannelClose", hresult_type, (HANDLE,), __check_status)
    # EXTERN_C HRESULT VCIAPI canChannelReadMessage( IN  HANDLE  hCanChn, IN  UINT32  dwMsTimeout, OUT PCANMSG2 pCanMsg );
    _canlib.map_symbol(
        "canChannelReadMessage",
        hresult_type,
        (HANDLE, ctypes.c_uint32, structures.PCANMSG2),
        __check_status,
    )
    # HRESULT canChannelPeekMessage(HANDLE hChannel,PCANMSG2 pCanMsg );
    _canlib.map_symbol(
        "canChannelPeekMessage",
        hresult_type,
        (HANDLE, structures.PCANMSG2),
        __check_status,
    )
    # HRESULT canChannelWaitTxEvent (HANDLE hChannel UINT32 dwMsTimeout );
    _canlib.map_symbol(
        "canChannelWaitTxEvent",
        hresult_type,
        (HANDLE, ctypes.c_uint32),
        __check_status,
    )
    # HRESULT canChannelWaitRxEvent (HANDLE hChannel, UINT32 dwMsTimeout );
    _canlib.map_symbol(
        "canChannelWaitRxEvent",
        hresult_type,
        (HANDLE, ctypes.c_uint32),
        __check_status,
    )
    # HRESULT canChannelPostMessage (HANDLE hChannel, PCANMSG2 pCanMsg );
    _canlib.map_symbol(
        "canChannelPostMessage",
        hresult_type,
        (HANDLE, structures.PCANMSG2),
        __check_status,
    )
    # HRESULT canChannelSendMessage (HANDLE hChannel, UINT32 dwMsTimeout, PCANMSG2 pCanMsg );
    _canlib.map_symbol(
        "canChannelSendMessage",
        hresult_type,
        (HANDLE, ctypes.c_uint32, structures.PCANMSG2),
        __check_status,
    )

    # EXTERN_C HRESULT VCIAPI canControlOpen( IN  HANDLE  hDevice, IN  UINT32  dwCanNo, OUT PHANDLE phCanCtl );
    _canlib.map_symbol(
        "canControlOpen",
        hresult_type,
        (HANDLE, ctypes.c_uint32, PHANDLE),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI
    #   canControlInitialize( IN HANDLE  hCanCtl,
    #                         IN UINT8   bOpMode,
    #                         IN UINT8   bExMode,
    #                         IN UINT8   bSFMode,
    #                         IN UINT8   bEFMode,
    #                         IN UINT32  dwSFIds,
    #                         IN UINT32  dwEFIds,
    #                         IN PCANBTP pBtpSDR,
    #                         IN PCANBTP pBtpFDR );
    _canlib.map_symbol(
        "canControlInitialize",
        hresult_type,
        (
            HANDLE,
            ctypes.c_uint8,
            ctypes.c_uint8,
            ctypes.c_uint8,
            ctypes.c_uint8,
            ctypes.c_uint32,
            ctypes.c_uint32,
            structures.PCANBTP,
            structures.PCANBTP,
        ),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI canControlClose( IN HANDLE hCanCtl );
    _canlib.map_symbol("canControlClose", hresult_type, (HANDLE,), __check_status)
    # EXTERN_C HRESULT VCIAPI canControlReset( IN HANDLE hCanCtl );
    _canlib.map_symbol("canControlReset", hresult_type, (HANDLE,), __check_status)
    # EXTERN_C HRESULT VCIAPI canControlStart( IN HANDLE hCanCtl, IN BOOL   fStart );
    _canlib.map_symbol(
        "canControlStart", hresult_type, (HANDLE, ctypes.c_long), __check_status
    )
    # EXTERN_C HRESULT VCIAPI canControlGetStatus( IN  HANDLE hCanCtl, OUT PCANLINESTATUS2 pStatus );
    _canlib.map_symbol(
        "canControlGetStatus",
        hresult_type,
        (HANDLE, structures.PCANLINESTATUS2),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI canControlGetCaps( IN  HANDLE hCanCtl, OUT PCANCAPABILITIES2 pCanCaps );
    _canlib.map_symbol(
        "canControlGetCaps",
        hresult_type,
        (HANDLE, structures.PCANCAPABILITIES2),
        __check_status,
    )
    # EXTERN_C HRESULT VCIAPI canControlSetAccFilter( IN HANDLE hCanCtl, IN BOOL   fExtend, IN UINT32 dwCode, IN UINT32 dwMask );
    _canlib.map_symbol(
        "canControlSetAccFilter",
        hresult_type,
        (HANDLE, ctypes.c_int, ctypes.c_uint32, ctypes.c_uint32),
        __check_status,
    )
    # EXTERN_C HRESULT canControlAddFilterIds (HANDLE hControl, BOOL fExtended, UINT32 dwCode, UINT32 dwMask);
    _canlib.map_symbol(
        "canControlAddFilterIds",
        hresult_type,
        (HANDLE, ctypes.c_int, ctypes.c_uint32, ctypes.c_uint32),
        __check_status,
    )
    # EXTERN_C HRESULT canControlRemFilterIds (HANDLE hControl, BOOL fExtendend, UINT32 dwCode, UINT32 dwMask );
    _canlib.map_symbol(
        "canControlRemFilterIds",
        hresult_type,
        (HANDLE, ctypes.c_int, ctypes.c_uint32, ctypes.c_uint32),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerOpen (HANDLE hDevice, UINT32 dwCanNo, PHANDLE phScheduler );
    _canlib.map_symbol(
        "canSchedulerOpen",
        hresult_type,
        (HANDLE, ctypes.c_uint32, PHANDLE),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerClose (HANDLE hScheduler );
    _canlib.map_symbol("canSchedulerClose", hresult_type, (HANDLE,), __check_status)
    # EXTERN_C HRESULT canSchedulerGetCaps (HANDLE hScheduler, PCANCAPABILITIES2 pCaps );
    _canlib.map_symbol(
        "canSchedulerGetCaps",
        hresult_type,
        (HANDLE, structures.PCANCAPABILITIES2),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerActivate ( HANDLE hScheduler, BOOL fEnable );
    _canlib.map_symbol(
        "canSchedulerActivate", hresult_type, (HANDLE, ctypes.c_int), __check_status
    )
    # EXTERN_C HRESULT canSchedulerAddMessage (HANDLE hScheduler, PCANCYCLICTXMSG2 pMessage, PUINT32 pdwIndex );
    _canlib.map_symbol(
        "canSchedulerAddMessage",
        hresult_type,
        (HANDLE, structures.PCANCYCLICTXMSG2, ctypes.POINTER(ctypes.c_uint32)),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerRemMessage (HANDLE hScheduler, UINT32 dwIndex );
    _canlib.map_symbol(
        "canSchedulerRemMessage",
        hresult_type,
        (HANDLE, ctypes.c_uint32),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerStartMessage (HANDLE hScheduler, UINT32 dwIndex, UINT16 dwCount );
    _canlib.map_symbol(
        "canSchedulerStartMessage",
        hresult_type,
        (HANDLE, ctypes.c_uint32, ctypes.c_uint16),
        __check_status,
    )
    # EXTERN_C HRESULT canSchedulerStopMessage (HANDLE hScheduler, UINT32 dwIndex );
    _canlib.map_symbol(
        "canSchedulerStopMessage",
        hresult_type,
        (HANDLE, ctypes.c_uint32),
        __check_status,
    )
    _canlib.vciInitialize()
except AttributeError:
    # In case _canlib == None meaning we're not on win32/no lib found
    pass
except Exception as e:
    log.warning("Could not initialize IXXAT VCI library: %s", e)
# ---------------------------------------------------------------------------


CAN_INFO_MESSAGES = {
    constants.CAN_INFO_START: "CAN started",
    constants.CAN_INFO_STOP: "CAN stopped",
    constants.CAN_INFO_RESET: "CAN reset",
}

CAN_ERROR_MESSAGES = {
    constants.CAN_ERROR_STUFF: "CAN bit stuff error",
    constants.CAN_ERROR_FORM: "CAN form error",
    constants.CAN_ERROR_ACK: "CAN acknowledgment error",
    constants.CAN_ERROR_BIT: "CAN bit error",
    constants.CAN_ERROR_CRC: "CAN CRC error",
    constants.CAN_ERROR_OTHER: "Other (unknown) CAN error",
}

CAN_STATUS_FLAGS = {
    constants.CAN_STATUS_TXPEND: "transmission pending",
    constants.CAN_STATUS_OVRRUN: "data overrun occurred",
    constants.CAN_STATUS_ERRLIM: "error warning limit exceeded",
    constants.CAN_STATUS_BUSOFF: "bus off",
    constants.CAN_STATUS_ININIT: "init mode active",
    constants.CAN_STATUS_BUSCERR: "bus coupling error",
}
# ----------------------------------------------------------------------------


[docs]class IXXATBus(BusABC): """The CAN Bus implemented for the IXXAT interface. .. warning:: This interface does implement efficient filtering of messages, but the filters have to be set in ``__init__`` using the ``can_filters`` parameter. Using :meth:`~can.BusABC.set_filters` does not work. """ @deprecated_args_alias( deprecation_start="4.0.0", deprecation_end="5.0.0", UniqueHardwareId="unique_hardware_id", rxFifoSize="rx_fifo_size", txFifoSize="tx_fifo_size", ) def __init__( self, channel: int, can_filters=None, receive_own_messages: int = False, unique_hardware_id: Optional[int] = None, extended: bool = True, rx_fifo_size: int = 1024, tx_fifo_size: int = 128, bitrate: int = 500000, data_bitrate: int = 2000000, sjw_abr: int = None, tseg1_abr: int = None, tseg2_abr: int = None, sjw_dbr: int = None, tseg1_dbr: int = None, tseg2_dbr: int = None, ssp_dbr: int = None, **kwargs, ): """ :param channel: The Channel id to create this bus with. :param can_filters: See :meth:`can.BusABC.set_filters`. :param receive_own_messages: Enable self-reception of sent messages. :param unique_hardware_id: unique_hardware_id to connect (optional, will use the first found if not supplied) :param extended: Default True, enables the capability to use extended IDs. :param rx_fifo_size: Receive fifo size (default 1024) :param tx_fifo_size: Transmit fifo size (default 128) :param bitrate: Channel bitrate in bit/s :param data_bitrate: Channel bitrate in bit/s (only in CAN-Fd if baudrate switch enabled). :param sjw_abr: Bus timing value sample jump width (arbitration). :param tseg1_abr: Bus timing value tseg1 (arbitration) :param tseg2_abr: Bus timing value tseg2 (arbitration) :param sjw_dbr: Bus timing value sample jump width (data) :param tseg1_dbr: Bus timing value tseg1 (data). Only takes effect with fd and bitrate switch enabled. :param tseg2_dbr: Bus timing value tseg2 (data). Only takes effect with fd and bitrate switch enabled. :param ssp_dbr: Secondary sample point (data). Only takes effect with fd and bitrate switch enabled. """ if _canlib is None: raise CanInterfaceNotImplementedError( "The IXXAT VCI library has not been initialized. Check the logs for more details." ) log.info("CAN Filters: %s", can_filters) # Configuration options self._receive_own_messages = receive_own_messages # Usually comes as a string from the config file channel = int(channel) if bitrate not in constants.CAN_BITRATE_PRESETS and ( tseg1_abr is None or tseg2_abr is None or sjw_abr is None ): raise ValueError( "To use bitrate {} (that has not predefined preset) is mandatory to use also parameters tseg1_abr, tseg2_abr and swj_abr".format( bitrate ) ) if data_bitrate not in constants.CAN_DATABITRATE_PRESETS and ( tseg1_dbr is None or tseg2_dbr is None or sjw_dbr is None ): raise ValueError( "To use data_bitrate {} (that has not predefined preset) is mandatory to use also parameters tseg1_dbr, tseg2_dbr and swj_dbr".format( data_bitrate ) ) if rx_fifo_size <= 0: raise ValueError("rx_fifo_size must be > 0") if tx_fifo_size <= 0: raise ValueError("tx_fifo_size must be > 0") if channel < 0: raise ValueError("channel number must be >= 0") self._device_handle = HANDLE() self._device_info = structures.VCIDEVICEINFO() self._control_handle = HANDLE() self._channel_handle = HANDLE() self._channel_capabilities = structures.CANCAPABILITIES2() self._message = structures.CANMSG2() self._payload = (ctypes.c_byte * 64)() # Search for supplied device if unique_hardware_id is None: log.info("Searching for first available device") else: log.info("Searching for unique HW ID %s", unique_hardware_id) _canlib.vciEnumDeviceOpen(ctypes.byref(self._device_handle)) while True: try: _canlib.vciEnumDeviceNext( self._device_handle, ctypes.byref(self._device_info) ) except StopIteration: if unique_hardware_id is None: raise VCIDeviceNotFoundError( "No IXXAT device(s) connected or device(s) in use by other process(es)." ) else: raise VCIDeviceNotFoundError( "Unique HW ID {} not connected or not available.".format( unique_hardware_id ) ) else: if (unique_hardware_id is None) or ( self._device_info.UniqueHardwareId.AsChar == bytes(unique_hardware_id, "ascii") ): break else: log.debug( "Ignoring IXXAT with hardware id '%s'.", self._device_info.UniqueHardwareId.AsChar.decode("ascii"), ) _canlib.vciEnumDeviceClose(self._device_handle) try: _canlib.vciDeviceOpen( ctypes.byref(self._device_info.VciObjectId), ctypes.byref(self._device_handle), ) except Exception as exception: raise CanInitializationError(f"Could not open device: {exception}") log.info("Using unique HW ID %s", self._device_info.UniqueHardwareId.AsChar) log.info( "Initializing channel %d in shared mode, %d rx buffers, %d tx buffers", channel, rx_fifo_size, tx_fifo_size, ) try: _canlib.canChannelOpen( self._device_handle, channel, constants.FALSE, ctypes.byref(self._channel_handle), ) except Exception as exception: raise CanInitializationError( f"Could not open and initialize channel: {exception}" ) # Signal TX/RX events when at least one frame has been handled _canlib.canChannelInitialize( self._channel_handle, rx_fifo_size, 1, tx_fifo_size, 1, 0, constants.CAN_FILTER_PASS, ) _canlib.canChannelActivate(self._channel_handle, constants.TRUE) pBtpSDR = IXXATBus._canptb_build( defaults=constants.CAN_BITRATE_PRESETS, bitrate=bitrate, tseg1=tseg1_abr, tseg2=tseg2_abr, sjw=sjw_abr, ssp=0, ) pBtpFDR = IXXATBus._canptb_build( defaults=constants.CAN_DATABITRATE_PRESETS, bitrate=data_bitrate, tseg1=tseg1_dbr, tseg2=tseg2_dbr, sjw=sjw_dbr, ssp=ssp_dbr if ssp_dbr is not None else tseg1_dbr, ) log.info( "Initializing control %d with SDR={%s}, FDR={%s}", channel, pBtpSDR, pBtpFDR, ) _canlib.canControlOpen( self._device_handle, channel, ctypes.byref(self._control_handle) ) _canlib.canControlGetCaps( self._control_handle, ctypes.byref(self._channel_capabilities) ) # check capabilities bOpMode = constants.CAN_OPMODE_UNDEFINED if ( self._channel_capabilities.dwFeatures & constants.CAN_FEATURE_STDANDEXT ) != 0: # controller supportes CAN_OPMODE_STANDARD and CAN_OPMODE_EXTENDED at the same time bOpMode |= constants.CAN_OPMODE_STANDARD # enable both 11 bits reception if extended: # parameter from configuration bOpMode |= constants.CAN_OPMODE_EXTENDED # enable 29 bits reception elif ( self._channel_capabilities.dwFeatures & constants.CAN_FEATURE_STDANDEXT ) != 0: log.warning( "Channel %d capabilities allow either basic or extended IDs, but not both. using %s according to parameter [extended=%s]", channel, "extended" if extended else "basic", "True" if extended else "False", ) bOpMode |= ( constants.CAN_OPMODE_EXTENDED if extended else constants.CAN_OPMODE_STANDARD ) if ( self._channel_capabilities.dwFeatures & constants.CAN_FEATURE_ERRFRAME ) != 0: bOpMode |= constants.CAN_OPMODE_ERRFRAME bExMode = constants.CAN_EXMODE_DISABLED if (self._channel_capabilities.dwFeatures & constants.CAN_FEATURE_EXTDATA) != 0: bExMode |= constants.CAN_EXMODE_EXTDATALEN if ( self._channel_capabilities.dwFeatures & constants.CAN_FEATURE_FASTDATA ) != 0: bExMode |= constants.CAN_EXMODE_FASTDATA _canlib.canControlInitialize( self._control_handle, bOpMode, bExMode, constants.CAN_FILTER_PASS, constants.CAN_FILTER_PASS, 0, 0, ctypes.byref(pBtpSDR), ctypes.byref(pBtpFDR), ) # With receive messages, this field contains the relative reception time of # the message in ticks. The resolution of a tick can be calculated from the fields # dwClockFreq and dwTscDivisor of the structure CANCAPABILITIES in accordance with the following formula: # frequency [1/s] = dwClockFreq / dwTscDivisor self._tick_resolution = ( self._channel_capabilities.dwTscClkFreq / self._channel_capabilities.dwTscDivisor ) # Setup filters before starting the channel if can_filters: log.info("The IXXAT VCI backend is filtering messages") # Disable every message coming in for extended in (0, 1): _canlib.canControlSetAccFilter( self._control_handle, extended, constants.CAN_ACC_CODE_NONE, constants.CAN_ACC_MASK_NONE, ) for can_filter in can_filters: # Filters define what messages are accepted code = int(can_filter["can_id"]) mask = int(can_filter["can_mask"]) extended = can_filter.get("extended", False) _canlib.canControlAddFilterIds( self._control_handle, 1 if extended else 0, code << 1, mask << 1 ) log.info("Accepting ID: 0x%X MASK: 0x%X", code, mask) # Start the CAN controller. Messages will be forwarded to the channel _canlib.canControlStart(self._control_handle, constants.TRUE) # For cyclic transmit list. Set when .send_periodic() is first called self._scheduler = None self._scheduler_resolution = None self.channel = channel # Usually you get back 3 messages like "CAN initialized" ecc... # Clear the FIFO by filter them out with low timeout for _ in range(rx_fifo_size): try: _canlib.canChannelReadMessage( self._channel_handle, 0, ctypes.byref(self._message) ) except (VCITimeout, VCIRxQueueEmptyError): break super().__init__(channel=channel, can_filters=None, **kwargs) @staticmethod def _canptb_build(defaults, bitrate, tseg1, tseg2, sjw, ssp): if bitrate in defaults: d = defaults[bitrate] if tseg1 is None: tseg1 = d.wTS1 if tseg2 is None: tseg2 = d.wTS2 if sjw is None: sjw = d.wSJW if ssp is None: ssp = d.wTDO dw_mode = d.dwMode else: dw_mode = 0 return structures.CANBTP( dwMode=dw_mode, dwBPS=bitrate, wTS1=tseg1, wTS2=tseg2, wSJW=sjw, wTDO=ssp, ) def _inWaiting(self): try: _canlib.canChannelWaitRxEvent(self._channel_handle, 0) except VCITimeout: return 0 else: return 1
[docs] def flush_tx_buffer(self): """Flushes the transmit buffer on the IXXAT""" # TODO #64: no timeout? _canlib.canChannelWaitTxEvent(self._channel_handle, constants.INFINITE)
def _recv_internal(self, timeout): """Read a message from IXXAT device.""" # TODO: handling CAN error messages? data_received = False if timeout == 0: # Peek without waiting try: _canlib.canChannelPeekMessage( self._channel_handle, ctypes.byref(self._message) ) except (VCITimeout, VCIRxQueueEmptyError, VCIError): # VCIError means no frame available (canChannelPeekMessage returned different from zero) return None, True else: if self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_DATA: data_received = True else: # Wait if no message available if timeout is None or timeout < 0: remaining_ms = constants.INFINITE t0 = None else: timeout_ms = int(timeout * 1000) remaining_ms = timeout_ms t0 = perf_counter() while True: try: _canlib.canChannelReadMessage( self._channel_handle, remaining_ms, ctypes.byref(self._message) ) except (VCITimeout, VCIRxQueueEmptyError): # Ignore the 2 errors, the timeout is handled manually with the perf_counter() pass else: # See if we got a data or info/error messages if self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_DATA: data_received = True break elif self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_INFO: log.info( CAN_INFO_MESSAGES.get( self._message.abData[0], f"Unknown CAN info message code {self._message.abData[0]}", ) ) elif ( self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_ERROR ): log.warning( CAN_ERROR_MESSAGES.get( self._message.abData[0], f"Unknown CAN error message code {self._message.abData[0]}", ) ) elif ( self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_STATUS ): log.info(_format_can_status(self._message.abData[0])) if self._message.abData[0] & constants.CAN_STATUS_BUSOFF: raise VCIBusOffError() elif ( self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_TIMEOVR ): pass else: log.warning("Unexpected message info type") if t0 is not None: remaining_ms = timeout_ms - int((perf_counter() - t0) * 1000) if remaining_ms < 0: break if not data_received: # Timed out / can message type is not DATA return None, True data_len = can.util.dlc2len(self._message.uMsgInfo.Bits.dlc) # The _message.dwTime is a 32bit tick value and will overrun, # so expect to see the value restarting from 0 rx_msg = Message( timestamp=self._message.dwTime / self._tick_resolution, # Relative time in s is_remote_frame=bool(self._message.uMsgInfo.Bits.rtr), is_fd=bool(self._message.uMsgInfo.Bits.edl), is_rx=True, is_error_frame=bool( self._message.uMsgInfo.Bits.type == constants.CAN_MSGTYPE_ERROR ), bitrate_switch=bool(self._message.uMsgInfo.Bits.fdr), error_state_indicator=bool(self._message.uMsgInfo.Bits.esi), is_extended_id=bool(self._message.uMsgInfo.Bits.ext), arbitration_id=self._message.dwMsgId, dlc=data_len, data=self._message.abData[:data_len], channel=self.channel, ) return rx_msg, True
[docs] def send(self, msg: Message, timeout: Optional[float] = None) -> None: """ Sends a message on the bus. The interface may buffer the message. :param msg: The message to send. :param timeout: Timeout after some time. :raise: :class:CanTimeoutError :class:CanOperationError """ # This system is not designed to be very efficient message = structures.CANMSG2() message.uMsgInfo.Bits.type = ( constants.CAN_MSGTYPE_ERROR if msg.is_error_frame else constants.CAN_MSGTYPE_DATA ) message.uMsgInfo.Bits.rtr = 1 if msg.is_remote_frame else 0 message.uMsgInfo.Bits.ext = 1 if msg.is_extended_id else 0 message.uMsgInfo.Bits.srr = 1 if self._receive_own_messages else 0 message.uMsgInfo.Bits.fdr = 1 if msg.bitrate_switch else 0 message.uMsgInfo.Bits.esi = 1 if msg.error_state_indicator else 0 message.uMsgInfo.Bits.edl = 1 if msg.is_fd else 0 message.dwMsgId = msg.arbitration_id if msg.dlc: # this dlc means number of bytes of payload message.uMsgInfo.Bits.dlc = can.util.len2dlc(msg.dlc) data_len_dif = msg.dlc - len(msg.data) data = msg.data + bytearray( [0] * data_len_dif ) # pad with zeros until required length adapter = (ctypes.c_uint8 * msg.dlc).from_buffer(data) ctypes.memmove(message.abData, adapter, msg.dlc) if timeout: _canlib.canChannelSendMessage( self._channel_handle, int(timeout * 1000), message ) else: _canlib.canChannelPostMessage(self._channel_handle, message)
def _send_periodic_internal(self, msgs, period, duration=None): """Send a message using built-in cyclic transmit list functionality.""" if self._scheduler is None: self._scheduler = HANDLE() _canlib.canSchedulerOpen(self._device_handle, self.channel, self._scheduler) caps = structures.CANCAPABILITIES2() _canlib.canSchedulerGetCaps(self._scheduler, caps) self._scheduler_resolution = ( caps.dwCmsClkFreq / caps.dwCmsDivisor ) # TODO: confirm _canlib.canSchedulerActivate(self._scheduler, constants.TRUE) return CyclicSendTask( self._scheduler, msgs, period, duration, self._scheduler_resolution )
[docs] def shutdown(self): if self._scheduler is not None: _canlib.canSchedulerClose(self._scheduler) _canlib.canChannelClose(self._channel_handle) _canlib.canControlStart(self._control_handle, constants.FALSE) _canlib.canControlClose(self._control_handle) _canlib.vciDeviceClose(self._device_handle)
[docs]class CyclicSendTask(LimitedDurationCyclicSendTaskABC, RestartableCyclicTaskABC): """A message in the cyclic transmit list.""" def __init__(self, scheduler, msgs, period, duration, resolution): super().__init__(msgs, period, duration) if len(self.messages) != 1: raise ValueError( "IXXAT Interface only supports periodic transmission of 1 element" ) self._scheduler = scheduler self._index = None self._count = int(duration / period) if duration else 0 self._msg = structures.CANCYCLICTXMSG2() self._msg.wCycleTime = int(round(period * resolution)) self._msg.dwMsgId = self.messages[0].arbitration_id self._msg.uMsgInfo.Bits.type = constants.CAN_MSGTYPE_DATA self._msg.uMsgInfo.Bits.ext = 1 if self.messages[0].is_extended_id else 0 self._msg.uMsgInfo.Bits.rtr = 1 if self.messages[0].is_remote_frame else 0 self._msg.uMsgInfo.Bits.dlc = self.messages[0].dlc for i, b in enumerate(self.messages[0].data): self._msg.abData[i] = b self.start()
[docs] def start(self): """Start transmitting message (add to list if needed).""" if self._index is None: self._index = ctypes.c_uint32() _canlib.canSchedulerAddMessage(self._scheduler, self._msg, self._index) _canlib.canSchedulerStartMessage(self._scheduler, self._index, self._count)
[docs] def pause(self): """Pause transmitting message (keep it in the list).""" _canlib.canSchedulerStopMessage(self._scheduler, self._index)
[docs] def stop(self): """Stop transmitting message (remove from list).""" # Remove it completely instead of just stopping it to avoid filling up # the list with permanently stopped messages _canlib.canSchedulerRemMessage(self._scheduler, self._index) self._index = None
def _format_can_status(status_flags: int): """ Format a status bitfield found in CAN_MSGTYPE_STATUS messages or in dwStatus field in CANLINESTATUS. Valid states are defined in the CAN_STATUS_* constants in cantype.h """ states = [] for flag, description in CAN_STATUS_FLAGS.items(): if status_flags & flag: states.append(description) status_flags &= ~flag if status_flags: states.append(f"unknown state 0x{status_flags:02x}") if states: return "CAN status message: {}".format(", ".join(states)) else: return "Empty CAN status message" def get_ixxat_hwids(): """Get a list of hardware ids of all available IXXAT devices.""" hwids = [] device_handle = HANDLE() device_info = structures.VCIDEVICEINFO() _canlib.vciEnumDeviceOpen(ctypes.byref(device_handle)) while True: try: _canlib.vciEnumDeviceNext(device_handle, ctypes.byref(device_info)) except StopIteration: break else: hwids.append(device_info.UniqueHardwareId.AsChar.decode("ascii")) _canlib.vciEnumDeviceClose(device_handle) return hwids