# Imports
from machine import Pin
import utime

# pins
pou_data = Pin(13, Pin.OUT)
pou_latch = Pin(14, Pin.OUT)
pou_clock = Pin(15, Pin.OUT)

def Shift(input):
  """Shift
  """
  global pou_data, pou_latch, pou_clock
  # put latch down to start data sending
  pou_latch.value(0)
  
  # load in the data in reverse order
  for i in range(len(input)):
    pou_clock.value(0)
    pou_data.value(int(input[i]))
    pou_clock.value(1)

  # pull latch up to store data on register
  pou_latch.value(1)

#main program, calling shift register function
bit_strings = [
    "00000001",
    "00000010",
    "00000100",
    "00001000",
    "00010000",
    "00100000",
    "01000000",
    "10000000"
]
i = 0

while True:
    if i == len(bit_strings):
        i = 0
    Shift(bit_strings[i])
    i += 1
    utime.sleep(0.5)