Simple test

Ensure your device works with this simple test.

examples/mcp2515_simpletest.py

# SPDX-FileCopyrightText: Copyright (c) 2020 Bryan Siepert for Adafruit Industries
#
# SPDX-License-Identifier: MIT
from time import sleep

import board
import busio
from digitalio import DigitalInOut

from adafruit_mcp2515 import MCP2515 as CAN
from adafruit_mcp2515.canio import Message, RemoteTransmissionRequest

cs = DigitalInOut(board.D5)
cs.switch_to_output()
spi = busio.SPI(board.SCK, board.MOSI, board.MISO)

can_bus = CAN(spi, cs, loopback=True, silent=True)  # use loopback to test without another device
while True:
    with can_bus.listen(timeout=1.0) as listener:
        message = Message(id=0x1234ABCD, data=b"adafruit", extended=True)
        send_success = can_bus.send(message)
        print("Send success:", send_success)
        message_count = listener.in_waiting()
        print(message_count, "messages available")
        for _i in range(message_count):
            msg = listener.receive()
            print("Message from ", hex(msg.id))
            if isinstance(msg, Message):
                print("message data:", msg.data)
            if isinstance(msg, RemoteTransmissionRequest):
                print("RTR length:", msg.length)
    sleep(1)