from machine import Pin, PWM, lightsleep
import time

#D18 = Pin(18, Pin.OUT)

'''
while (True):
    D18.on()
    time.sleep_ms(500)
    D18.off()
    time.sleep_ms(500)
'''
pwm0 = PWM(Pin(18))
pwm0.freq(50)
i=0
z=False
while (True):
    pwm0.duty(int((i/100) * 1023))
    if (i >= 100):
        z=True
    elif (i <= 0):
        z=False
    if (z==True):
        i=i-10
    else:
        i=i+10
    time.sleep(200)
    print(i)