#!/usr/bin/env python # Author: Jon Trulson # Copyright (c) 2016 Intel Corporation. # # Permission is hereby granted, free of charge, to any person obtaining # a copy of this software and associated documentation files (the # "Software"), to deal in the Software without restriction, including # without limitation the rights to use, copy, modify, merge, publish, # distribute, sublicense, and/or sell copies of the Software, and to # permit persons to whom the Software is furnished to do so, subject to # the following conditions: # # The above copyright notice and this permission notice shall be # included in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. from __future__ import print_function import time, sys, signal, atexit from upm import pyupm_mcp2515 as MCP2515 def main(): # Instantiate a MCP2515 on SPI bus 0 using a hw CS pin (-1). sensor = MCP2515.MCP2515(0, -1) ## Exit handlers ## # This function stops python from printing a stacktrace when you # hit control-C def SIGINTHandler(signum, frame): raise SystemExit # This function lets you run code on exit, including functions from sensor def exitHandler(): print("Exiting") sys.exit(0) # Register exit handlers atexit.register(exitHandler) signal.signal(signal.SIGINT, SIGINTHandler) print("Setting loopback mode...") # set the mode to loopback mode. In loopback mode, transmitted # packets are sent directly to an appropriate receive buffer # without actually going out onto the CAN bus. sensor.setOpmode(MCP2515.MCP2515_OPMODE_LOOPBACK); # lets build up a packet and try loading it (8 bytes max). myPayload = "01234567"; print("Loading a packet of 8 numbers (0-7) into a TX buffer...") sensor.loadTXBuffer(MCP2515.MCP2515_TX_BUFFER0, 0, False, False, myPayload); # now lets try to transmit it print("Transmitting packet...") sensor.transmitBuffer(MCP2515.MCP2515_TX_BUFFER0, True); print("Transmit successful") # There should now be a packet waiting for us in RXB0 if (sensor.rxStatusMsgs() == MCP2515.MCP2515_RXMSG_RXB0): print("Packet received in RXB0, decoding...") # now lets retrieve and print it sensor.getRXMsg(MCP2515.MCP2515_RX_BUFFER0); sensor.printMsg(); else: print("No packet found, how strange.") print("Exiting...") if __name__ == '__main__': main()