title: Trying to get SPI running on RaspPi 3 (Loopback)
body: <p>cannot figure out how to do the loopback test from the spidev module.
  Executing provided spidev_test.c file works. Not yet in Python.</p>
  
  <pre><code>import spidev
  import time
  
  spi = spidev.SpiDev()
  spi.loop = True
  spi.open(0,0)
  
  try:
      while True:
          spi.writebytes([0xAA, 0xFF])
          time.sleep(0.01)
          print(spi.readbytes(2))    
  except KeyboardInterrupt:
      spi.close()
  </code></pre>