Raspberry Pi SPI loopback test code

spi_loopback_test.py

#!/usr/bin/env python

# loopback test script
#   connect MOSI and MISO

import spidev
import time

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

def BytesToHex(Bytes):
    return ''.join(["0x%02X " % x for x in Bytes]).strip()

try:
    while True:
        resp = spi.xfer2([0x01, 0x02])
        print BytesToHex(resp)
        time.sleep(1)

except KeyboardInterrupt:
    spi.close()