#!/usr/bin/python
 
import spidev
import os
import time

delay = 0.2

spi = spidev.SpiDev()
spi.open(0,0)
spi.max_speed_hz=1000000

def readChannel(channel):
  val = spi.xfer2([1,(8+channel)<<4,0])
  data = ((val[1]&3) << 8) + val[2]
  return data

if __name__ == "__main__":
  try:
	while True:
	  val = readChannel(0)
	  if (val != 0):
		print(val)
	  time.sleep(delay)
	  
  except KeyboardInterrupt:
	print "Cancel."