gbasend.py

#!/usr/bin/python

# arduino          rpi
# 8             -> 13 (gpio 3)
# 9 (pwm)       -> 33 (pwm1)
# 10 (pwm ss)   -> 23 (gpio 14)
# 11 (pwm mosi) -> 19 (gpio 12)

# view from front of CABLE
# annotated with colors of crappy $1 ebay link cable
#   T
# 1 3 5         1 3v, xxx 3 SI, wht 5 SC, red
# 2 4 6         2 SO, blk 4 SD, grn 6 GN, xxx

import wiringpi
import time

SI = 0
SO = 1
SC = 2

SD = 3

wiringpi.wiringPiSetup()
wiringpi.pinMode(SI, 1)
wiringpi.pinMode(SO, 0)
wiringpi.pinMode(SC, 1)
wiringpi.pinMode(SD, 1)

def sendbytes(u16list):
	wiringpi.digitalWrite(SC, 1) # mode 3 clock idle
	res = ''

	for u16 in u16list:
		wiringpi.digitalWrite(SD, 0) # slave select

		bstr = bin(u16)[2:].zfill(16)
		# print "send " + bstr

		for i in reversed(xrange(16)):

			wiringpi.digitalWrite(SC, 1) # mode 3 clock hi

			if bstr[i] == '0':
				wiringpi.digitalWrite(SI, 0) # send 0
			else:
				wiringpi.digitalWrite(SI, 1) # send 1

			wiringpi.digitalWrite(SC, 0) # mode 3 clock lo (toggle)

			time.sleep(.001)

			res = str(wiringpi.digitalRead(SO)) + res

			wiringpi.digitalWrite(SC, 1) # mode 3 clock hi (sample)

			time.sleep(.001)

		wiringpi.digitalWrite(SD, 1) # slave idle

	# print "read " + res
	return int(res, 2)

recd = 0
while recd != 0x72026202:
	recd = sendbytes([0x6202, 0x0000])
	print "got 0x{0:08x}".format(recd)
	time.sleep(.2)