# coding: utf-8
"""
Enable basic CAN over a PCAN USB device.
"""
from __future__ import absolute_import, print_function, division
import logging
import sys
import time
import can
from can import CanError, Message, BusABC
from can.bus import BusState
from can.util import len2dlc, dlc2len
from .basic import *
boottimeEpoch = 0
try:
import uptime
import datetime
boottimeEpoch = (uptime.boottime() - datetime.datetime.utcfromtimestamp(0)).total_seconds()
except:
boottimeEpoch = 0
try:
# Try builtin Python 3 Windows API
from _overlapped import CreateEvent
from _winapi import WaitForSingleObject, WAIT_OBJECT_0, INFINITE
HAS_EVENTS = True
except ImportError:
try:
# Try pywin32 package
from win32event import CreateEvent
from win32event import WaitForSingleObject, WAIT_OBJECT_0, INFINITE
HAS_EVENTS = True
except ImportError:
# Use polling instead
HAS_EVENTS = False
try:
# new in 3.3
timeout_clock = time.perf_counter
except AttributeError:
# deprecated in 3.3
timeout_clock = time.clock
# Set up logging
log = logging.getLogger('can.pcan')
pcan_bitrate_objs = {1000000 : PCAN_BAUD_1M,
800000 : PCAN_BAUD_800K,
500000 : PCAN_BAUD_500K,
250000 : PCAN_BAUD_250K,
125000 : PCAN_BAUD_125K,
100000 : PCAN_BAUD_100K,
95000 : PCAN_BAUD_95K,
83000 : PCAN_BAUD_83K,
50000 : PCAN_BAUD_50K,
47000 : PCAN_BAUD_47K,
33000 : PCAN_BAUD_33K,
20000 : PCAN_BAUD_20K,
10000 : PCAN_BAUD_10K,
5000 : PCAN_BAUD_5K}
pcan_fd_parameter_list = ['nom_brp', 'nom_tseg1', 'nom_tseg2', 'nom_sjw', 'data_brp', 'data_tseg1', 'data_tseg2', 'data_sjw']
[docs]class PcanBus(BusABC):
def __init__(self, channel='PCAN_USBBUS1', state=BusState.ACTIVE, bitrate=500000, *args, **kwargs):
"""A PCAN USB interface to CAN.
On top of the usual :class:`~can.Bus` methods provided,
the PCAN interface includes the :meth:`~can.interface.pcan.PcanBus.flash`
and :meth:`~can.interface.pcan.PcanBus.status` methods.
:param str channel:
The can interface name. An example would be 'PCAN_USBBUS1'
Default is 'PCAN_USBBUS1'
:param can.bus.BusState state:
BusState of the channel.
Default is ACTIVE
: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.
"""
self.channel_info = channel
self.fd = kwargs.get('fd', False)
pcan_bitrate = pcan_bitrate_objs.get(bitrate, PCAN_BAUD_500K)
hwtype = PCAN_TYPE_ISA
ioport = 0x02A0
interrupt = 11
self.m_objPCANBasic = PCANBasic()
self.m_PcanHandle = globals()[channel]
if state is BusState.ACTIVE or state is BusState.PASSIVE:
self.state = state
else:
raise ArgumentError("BusState must be Active or Passive")
if self.fd:
f_clock_val = kwargs.get('f_clock', None)
if f_clock_val is None:
f_clock = "{}={}".format('f_clock_mhz', kwargs.get('f_clock_mhz', None))
else:
f_clock = "{}={}".format('f_clock', kwargs.get('f_clock', None))
fd_parameters_values = [f_clock] + ["{}={}".format(key, kwargs.get(key, None)) for key in pcan_fd_parameter_list if kwargs.get(key, None) is not None]
self.fd_bitrate = ' ,'.join(fd_parameters_values).encode("ascii")
result = self.m_objPCANBasic.InitializeFD(self.m_PcanHandle, self.fd_bitrate)
else:
result = self.m_objPCANBasic.Initialize(self.m_PcanHandle, pcan_bitrate, hwtype, ioport, interrupt)
if result != PCAN_ERROR_OK:
raise PcanError(self._get_formatted_error(result))
if HAS_EVENTS:
self._recv_event = CreateEvent(None, 0, 0, None)
result = self.m_objPCANBasic.SetValue(
self.m_PcanHandle, PCAN_RECEIVE_EVENT, self._recv_event)
if result != PCAN_ERROR_OK:
raise PcanError(self._get_formatted_error(result))
super(PcanBus, self).__init__(channel=channel, state=state, bitrate=bitrate, *args, **kwargs)
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, 0)
if stsReturn[0] != PCAN_ERROR_OK:
strings = []
for b in bits(error):
stsReturn = self.m_objPCANBasic.GetErrorText(b, 0)
if stsReturn[0] != PCAN_ERROR_OK:
text = "An error occurred. Error-code's text ({0: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
[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
def _recv_internal(self, timeout):
if HAS_EVENTS:
# We will utilize events for the timeout handling
timeout_ms = int(timeout * 1000) if timeout is not None else INFINITE
elif timeout is not None:
# Calculate max time
end_time = timeout_clock() + timeout
#log.debug("Trying to read a msg")
result = None
while result is None:
if self.fd:
result = self.m_objPCANBasic.ReadFD(self.m_PcanHandle)
else:
result = self.m_objPCANBasic.Read(self.m_PcanHandle)
if result[0] == PCAN_ERROR_QRCVEMPTY:
if HAS_EVENTS:
result = None
val = WaitForSingleObject(self._recv_event, timeout_ms)
if val != WAIT_OBJECT_0:
return None, False
elif timeout is not None and timeout_clock() >= end_time:
return None, False
else:
result = None
time.sleep(0.001)
elif result[0] & (PCAN_ERROR_BUSLIGHT | PCAN_ERROR_BUSHEAVY):
log.warning(self._get_formatted_error(result[0]))
return None, False
elif result[0] != PCAN_ERROR_OK:
raise PcanError(self._get_formatted_error(result[0]))
theMsg = result[1]
itsTimeStamp = result[2]
#log.debug("Received a message")
is_extended_id = (theMsg.MSGTYPE & PCAN_MESSAGE_EXTENDED.value) == PCAN_MESSAGE_EXTENDED.value
is_remote_frame = (theMsg.MSGTYPE & PCAN_MESSAGE_RTR.value) == PCAN_MESSAGE_RTR.value
is_fd = (theMsg.MSGTYPE & PCAN_MESSAGE_FD.value) == PCAN_MESSAGE_FD.value
bitrate_switch = (theMsg.MSGTYPE & PCAN_MESSAGE_BRS.value) == PCAN_MESSAGE_BRS.value
error_state_indicator = (theMsg.MSGTYPE & PCAN_MESSAGE_ESI.value) == PCAN_MESSAGE_ESI.value
is_error_frame = (theMsg.MSGTYPE & PCAN_MESSAGE_ERRFRAME.value) == PCAN_MESSAGE_ERRFRAME.value
if self.fd:
dlc = dlc2len(theMsg.DLC)
timestamp = boottimeEpoch + (itsTimeStamp.value / (1000.0 * 1000.0))
else:
dlc = theMsg.LEN
timestamp = boottimeEpoch + ((itsTimeStamp.micros + 1000 * itsTimeStamp.millis + 0x100000000 * 1000 * itsTimeStamp.millis_overflow) / (1000.0 * 1000.0))
rx_msg = Message(timestamp=timestamp,
arbitration_id=theMsg.ID,
is_extended_id=is_extended_id,
is_remote_frame=is_remote_frame,
is_error_frame=is_error_frame,
dlc=dlc,
data=theMsg.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
if platform.system() == 'Darwin':
CANMsg = TPCANMsgFDMac()
else:
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] = msg.data[i]
log.debug("Data: %s", msg.data)
log.debug("Type: %s", type(msg.data))
result = self.m_objPCANBasic.WriteFD(self.m_PcanHandle, CANMsg)
else:
# create a TPCANMsg message structure
if platform.system() == 'Darwin':
CANMsg = TPCANMsgMac()
else:
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 msg.is_remote_frame:
CANMsg.MSGTYPE = msgType.value | PCAN_MESSAGE_RTR.value
else:
# copy data
for i in range(CANMsg.LEN):
CANMsg.DATA[i] = msg.data[i]
log.debug("Data: %s", msg.data)
log.debug("Type: %s", type(msg.data))
result = self.m_objPCANBasic.Write(self.m_PcanHandle, CANMsg)
if result != PCAN_ERROR_OK:
raise PcanError("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(PcanBus, self).shutdown()
self.m_objPCANBasic.Uninitialize(self.m_PcanHandle)
@property
def state(self):
return self._state
@state.setter
def state(self, new_state):
self._state = new_state
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)
class PcanError(CanError):
"""
A generic error on a PCAN bus.
"""
pass