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SocketCAN (native) cyclic improvements #323

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Merged
christiansandberg merged 3 commits into from
Jun 12, 2018
Merged

SocketCAN (native) cyclic improvements #323

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7f20963
Keep periodic transmission on data update
christiansandberg Jun 9, 2018
123caf4
Fix restart of modified messages
christiansandberg Jun 9, 2018
d65f68d
Fix documentation
christiansandberg Jun 12, 2018
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Keep periodic transmission on data update 
Use BCM for setting duration
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@christiansandberg
christiansandberg committed Jun 9, 2018
commit 7f20963fd3933a1e74be5143caa4b05196b4e475
34 changes: 21 additions & 13 deletions can/interfaces/socketcan/socketcan_native.py
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@
"""

import logging
import threading

import os
import select
Expand Down Expand Up @@ -143,6 +142,10 @@ def split_time(value):
return build_bcm_header(opcode, flags, count, ival1_seconds, ival1_usec, ival2_seconds, ival2_usec, can_id, nframes)


def build_bcm_update_header(can_id, msg_flags):
return build_bcm_header(CAN_BCM_TX_SETUP, msg_flags, 0, 0, 0, 0, 0, can_id, 1)


def dissect_can_frame(frame):
can_id, can_dlc, flags = CAN_FRAME_HEADER_STRUCT.unpack_from(frame)
if len(frame) != CANFD_MTU:
Expand Down Expand Up @@ -224,22 +227,31 @@ class CyclicSendTask(SocketCanBCMBase, LimitedDurationCyclicSendTaskABC,

"""

def __init__(self, channel, message, period):
def __init__(self, channel, message, period, duration=None):
"""
:param channel: The name of the CAN channel to connect to.
:param message: The message to be sent periodically.
:param period: The rate in seconds at which to send the message.
"""
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@felixdivo felixdivo Jun 12, 2018

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maybe add the param to the docs here

super(CyclicSendTask, self).__init__(channel, message, period, duration=None)
super(CyclicSendTask, self).__init__(channel, message, period, duration)
self.duration = duration
self._tx_setup(message)
self.message = message

def _tx_setup(self, message):
# Create a low level packed frame to pass to the kernel
self.can_id_with_flags = _add_flags_to_can_id(message)
self.flags = CAN_FD_FRAME if message.is_fd else 0
header = build_bcm_transmit_header(self.can_id_with_flags, 0, 0.0,
self.period, self.flags)
if self.duration:
count = int(self.duration / self.period)
ival1 = self.period
ival2 = 0
else:
count = 0
ival1 = 0
ival2 = self.period
header = build_bcm_transmit_header(self.can_id_with_flags, count, ival1,
ival2, self.flags)
frame = build_can_frame(message)
log.debug("Sending BCM command")
send_bcm(self.bcm_socket, header + frame)
Expand All @@ -262,7 +274,9 @@ def modify_data(self, message):
Note the Message must have the same :attr:`~can.Message.arbitration_id`.
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@felixdivo felixdivo Jun 12, 2018

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... "like the one of the message given in the constructor"

"""
assert message.arbitration_id == self.can_id, "You cannot modify the can identifier"
self._tx_setup(message)
header = build_bcm_update_header(self.can_id_with_flags, self.flags)
frame = build_can_frame(message)
send_bcm(self.bcm_socket, header + frame)

def start(self):
self._tx_setup(self.message)
Expand Down Expand Up @@ -481,13 +495,7 @@ def send(self, msg, timeout=None):
raise can.CanError("can.socketcan_native failed to transmit: {}".format(error_message))

def send_periodic(self, msg, period, duration=None):
task = CyclicSendTask(self.channel, msg, period)

if duration is not None:
stop_timer = threading.Timer(duration, task.stop)
stop_timer.start()

return task
return CyclicSendTask(self.channel, msg, period, duration)

def _apply_filters(self, filters):
try:
Expand Down