""" NI-XNET interface module. Implementation references: NI-XNET Hardware and Software Manual: https://www.ni.com/pdf/manuals/372840h.pdf NI-XNET Python implementation: https://github.com/ni/nixnet-python Authors: Javier Rubio Giménez , Jose A. Escobar """ import logging import sys import time import struct from can import BusABC, Message from ..exceptions import CanInitializationError, CanOperationError logger = logging.getLogger(__name__) if sys.platform == "win32": try: from nixnet import ( session, types, constants, errors, system, database, XnetError, ) except ImportError as error: raise ImportError("NIXNET python module cannot be loaded") from error else: raise NotImplementedError("NiXNET only supported on Win32 platforms") class NiXNETcanBus(BusABC): """ The CAN Bus implemented for the NI-XNET interface. """ def __init__( self, channel, can_filters=None, bitrate=None, fd=False, fd_bitrate=None, brs=False, can_termination=False, log_errors=True, **kwargs, ): """ :param str channel: Name of the object to open (e.g. 'CAN0') :param int bitrate: Bitrate in bits/s :param list can_filters: See :meth:`can.BusABC.set_filters`. :param bool log_errors: If True, communication errors will appear as CAN messages with ``is_error_frame`` set to True and ``arbitration_id`` will identify the error (default True) :raises can.exceptions.CanInitializationError: If starting communication fails """ self._rx_queue = [] self.channel = channel self.channel_info = "NI-XNET: " + channel # Set database for the initialization if not fd: database_name = ":memory:" else: if not brs: database_name = ":can_fd:" else: database_name = ":can_fd_brs:" try: # We need two sessions for this application, one to send frames and another to receive them self.__session_send = session.FrameOutStreamSession( channel, database_name=database_name ) self.__session_receive = session.FrameInStreamSession( channel, database_name=database_name ) # We stop the sessions to allow reconfiguration, as by default they autostart at creation self.__session_send.stop() self.__session_receive.stop() # See page 1017 of NI-XNET Hardware and Software Manual to set custom can configuration if bitrate: self.__session_send.intf.baud_rate = bitrate self.__session_receive.intf.baud_rate = bitrate if fd_bitrate: # See page 951 of NI-XNET Hardware and Software Manual to set custom can configuration self.__session_send.intf.can_fd_baud_rate = fd_bitrate self.__session_receive.intf.can_fd_baud_rate = fd_bitrate if can_termination: self.__session_send.intf.can_term = constants.CanTerm.ON self.__session_receive.intf.can_term = constants.CanTerm.ON self.__session_receive.queue_size = 512 # Once that all the parameters have been restarted, we start the sessions self.__session_send.start() self.__session_receive.start() except errors.XnetError as error: raise CanInitializationError( f"{error.args[0]} ({error.error_type})", error.error_code ) from None self._is_filtered = False super(NiXNETcanBus, self).__init__( channel=channel, can_filters=can_filters, bitrate=bitrate, log_errors=log_errors, **kwargs, ) def _recv_internal(self, timeout): try: if len(self._rx_queue) == 0: fr = self.__session_receive.frames.read(4, timeout=0) for f in fr: self._rx_queue.append(f) can_frame = self._rx_queue.pop(0) # Timestamp should be converted from raw frame format(100ns increment from(12:00 a.m. January 1 1601 Coordinated # Universal Time (UTC)) to epoch time(number of seconds from January 1, 1970 (midnight UTC/GMT)) msg = Message( timestamp=can_frame.timestamp / 10000000.0 - 11644473600, channel=self.channel, is_remote_frame=can_frame.type == constants.FrameType.CAN_REMOTE, is_error_frame=can_frame.type == constants.FrameType.CAN_BUS_ERROR, is_fd=( can_frame.type == constants.FrameType.CANFD_DATA or can_frame.type == constants.FrameType.CANFDBRS_DATA ), bitrate_switch=can_frame.type == constants.FrameType.CANFDBRS_DATA, is_extended_id=can_frame.identifier.extended, # Get identifier from CanIdentifier structure arbitration_id=can_frame.identifier.identifier, dlc=len(can_frame.payload), data=can_frame.payload, ) return msg, self._filters is None except Exception: return None, self._filters is None def send(self, msg, timeout=None): """ Send a message using NI-XNET. :param can.Message msg: Message to send :param float timeout: Max time to wait for the device to be ready in seconds, None if time is infinite :raises can.exceptions.CanOperationError: If writing to transmit buffer fails. It does not wait for message to be ACKed currently. """ if timeout is None: timeout = constants.TIMEOUT_INFINITE if msg.is_remote_frame: type_message = constants.FrameType.CAN_REMOTE elif msg.is_error_frame: type_message = constants.FrameType.CAN_BUS_ERROR elif msg.is_fd: if msg.bitrate_switch: type_message = constants.FrameType.CANFDBRS_DATA else: type_message = constants.FrameType.CANFD_DATA else: type_message = constants.FrameType.CAN_DATA can_frame = types.CanFrame( types.CanIdentifier(msg.arbitration_id, msg.is_extended_id), type=type_message, payload=msg.data, ) try: self.__session_send.frames.write([can_frame], timeout) except errors.XnetError as error: raise CanOperationError( f"{error.args[0]} ({error.error_type})", error.error_code ) from None def reset(self): """ Resets network interface. Stops network interface, then resets the CAN chip to clear the CAN error counters (clear error passive state). Resetting includes clearing all entries from read and write queues. """ self.__session_send.flush() self.__session_receive.flush() self.__session_send.stop() self.__session_receive.stop() self.__session_send.start() self.__session_receive.start() def shutdown(self): """Close object.""" super().shutdown() self.__session_send.flush() self.__session_receive.flush() self.__session_send.stop() self.__session_receive.stop() self.__session_send.close() self.__session_receive.close() @staticmethod def _detect_available_configs(): configs = [] try: with system.System() as nixnet_system: for interface in nixnet_system.intf_refs_can: cahnnel = str(interface) logger.debug( "Found channel index %d: %s", interface.port_num, cahnnel ) configs.append( { "interface": "nixnet", "channel": cahnnel, "can_term_available": interface.can_term_cap == constants.CanTermCap.YES, } ) except XnetError as error: logger.debug("An error occured while searching for configs: %s", str(error)) return configs