# PWM1.py
# LED dimming

import RPi.GPIO as GPIO
import time

P_LED = 22 # adapt to your wiring
fPWM = 50  # Hz (not higher with software PWM)

def setup():
    global pwm
    GPIO.setmode(GPIO.BOARD)
    GPIO.setup(P_LED, GPIO.OUT)
    pwm = GPIO.PWM(P_LED, fPWM)
    pwm.start(0)
    
print "starting"
setup()
duty = 0
isIncreasing = True
while True:
    pwm.ChangeDutyCycle(duty)
    print "D =", duty, "%"
    if isIncreasing:
        duty += 10
    else:
        duty -= 10
    if duty == 100:
        isIncreasing = False
    if duty == 0:
        isIncreasing = True
    time.sleep(1)