import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
SCLPin=17
SDOPin=4

HALF_BIT_TIME=.001
CHARACTER_DELAY=5*HALF_BIT_TIME

NUM_BITS=16

GPIO.setup(SCLPin,GPIO.OUT)
GPIO.setup(SDOPin,GPIO.IN)

GPIO.output(SCLPin,GPIO.HIGH)
time.sleep(HALF_BIT_TIME)
oldKey=18

try:
        while True:
                button=1
                time.sleep(CHARACTER_DELAY)

                while button < 17:
                        print_button=button
                        if (print_button==17):
                                print_button=1

                        GPIO.output(SCLPin,GPIO.LOW)
                        time.sleep(HALF_BIT_TIME)
                        keyval=GPIO.input(SDOPin)
                        if not keyval:
                                pressed=True
                                if(oldKey!=button) :
                                        print(print_button)
                                        oldKey=button
                        GPIO.output(SCLPin,GPIO.HIGH)
                        time.sleep(HALF_BIT_TIME)

                        button+=1

                pressed=False
except KeyboardInterrupt:
        pass
        GPIO.cleanup()