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#!/usr/bin/env python3
"""
This example exercises the periodic sending capabilities.
Expects a vcan0 interface:
python3 -m examples.cyclic
"""
import logging
import time
import can
logging.basicConfig(level=logging.INFO)
def simple_periodic_send(bus):
"""
Sends a message every 20ms with no explicit timeout
Sleeps for 2 seconds then stops the task.
"""
print("Starting to send a message every 200ms for 2s")
msg = can.Message(
arbitration_id=0x123, data=[1, 2, 3, 4, 5, 6], is_extended_id=False
)
task = bus.send_periodic(msg, 0.20)
assert isinstance(task, can.CyclicSendTaskABC)
time.sleep(2)
task.stop()
print("stopped cyclic send")
def limited_periodic_send(bus):
"""Send using LimitedDurationCyclicSendTaskABC."""
print("Starting to send a message every 200ms for 1s")
msg = can.Message(
arbitration_id=0x12345678, data=[0, 0, 0, 0, 0, 0], is_extended_id=True
)
task = bus.send_periodic(msg, 0.20, 1, store_task=False)
if not isinstance(task, can.LimitedDurationCyclicSendTaskABC):
print("This interface doesn't seem to support LimitedDurationCyclicSendTaskABC")
task.stop()
return
time.sleep(2)
print("Cyclic send should have stopped as duration expired")
# Note the (finished) task will still be tracked by the Bus
# unless we pass `store_task=False` to bus.send_periodic
# alternatively calling stop removes the task from the bus
# task.stop()
def test_periodic_send_with_modifying_data(bus):
"""Send using ModifiableCyclicTaskABC."""
print("Starting to send a message every 200ms. Initial data is four consecutive 1s")
msg = can.Message(arbitration_id=0x0CF02200, data=[1, 1, 1, 1])
task = bus.send_periodic(msg, 0.20)
if not isinstance(task, can.ModifiableCyclicTaskABC):
print("This interface doesn't seem to support modification")
task.stop()
return
time.sleep(2)
print("Changing data of running task to begin with 99")
msg.data[0] = 0x99
task.modify_data(msg)
time.sleep(2)
task.stop()
print("stopped cyclic send")
print("Changing data of stopped task to single ff byte")
msg.data = bytearray([0xFF])
msg.dlc = 1
task.modify_data(msg)
time.sleep(1)
print("starting again")
task.start()
time.sleep(1)
task.stop()
print("done")
# Will have to consider how to expose items like this. The socketcan
# interfaces will continue to support it... but the top level api won't.
# def test_dual_rate_periodic_send():
# """Send a message 10 times at 1ms intervals, then continue to send every 500ms"""
# msg = can.Message(arbitration_id=0x123, data=[0, 1, 2, 3, 4, 5])
# print("Creating cyclic task to send message 10 times at 1ms, then every 500ms")
# task = can.interface.MultiRateCyclicSendTask('vcan0', msg, 10, 0.001, 0.50)
# time.sleep(2)
#
# print("Changing data[0] = 0x42")
# msg.data[0] = 0x42
# task.modify_data(msg)
# time.sleep(2)
#
# task.stop()
# print("stopped cyclic send")
#
# time.sleep(2)
#
# task.start()
# print("starting again")
# time.sleep(2)
# task.stop()
# print("done")
def main():
"""Test different cyclic sending tasks."""
reset_msg = can.Message(
arbitration_id=0x00, data=[0, 0, 0, 0, 0, 0], is_extended_id=False
)
# this uses the default configuration (for example from environment variables, or a
# config file) see https://python-can.readthedocs.io/en/stable/configuration.html
with can.Bus() as bus:
bus.send(reset_msg)
simple_periodic_send(bus)
bus.send(reset_msg)
limited_periodic_send(bus)
test_periodic_send_with_modifying_data(bus)
# print("Carrying out multirate cyclic test for {} interface".format(interface))
# can.rc['interface'] = interface
# test_dual_rate_periodic_send()
time.sleep(2)
if __name__ == "__main__":
main()
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