from machine import Pin, PWM
from time import sleep

led = PWM(Pin(2))  # configurar GPI032 como salida PWM
led.freq(5)    # Frecuencia de 500 Hz 

while True: 
    for duty in range(0, 1024, 100):    #  Incrementar el duty cycle 
        led.duty(duty)
        sleep(0.5)