drive a 4-bit shift register via GPIO (2 outputs) on Raspberry Pi

gpshiftreg.py

#!/usr/bin/python

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BOARD)

CLOCK = 36 # G16
DATA = 7 # G4

GPIO.setwarnings(False)
GPIO.setup([CLOCK, DATA], GPIO.OUT, initial=GPIO.LOW)

def clock_in_data(bits):
	#print "clock_in_data",bits
	for i in range(0, len(bits)):
		GPIO.output(DATA, bits[i])

		# falling transition -> clocks in data
		GPIO.output(CLOCK, True)
		time.sleep(0.001)
		GPIO.output(CLOCK, False)

# an interesting "bouncing" pattern
bits = [
	[1,0,0,0],
	[0,1,0,0],
	[0,0,1,0],
	[0,0,0,1],
	[0,0,1,0],
	[0,1,0,0],
]

while True:
	for line in bits:
		clock_in_data(line)
		time.sleep(0.5)