mraa/examples/python/spi_loopback.py

#!/usr/bin/env python

# Author: Brendan Le Foll <brendan.le.foll@intel.com>
# Copyright (c) 2015 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
#
# Example Usage: Loopbacks data between MISO and MOSI 100 times

import mraa as m
import random as rand

# intialise SPI
dev = m.Spi(0)

for x in range(0,100):
    txbuf = bytearray(4)
    for y in range(0,4):
        txbuf[y] = rand.randrange(0, 256)

    # send and receive data through SPI
    rxbuf = dev.write(txbuf)
    if rxbuf != txbuf:
        print("Data mismatch!")
        exit(1)