import board
import pwmio
import time

led = pwmio.PWMOut(board.GP2, frequency=1000)

while True: 
    led.duty_cycle = 65535 #PWM al 100%
    time.sleep(1)
    led.duty_cycle = 49152 #PWM al 75%
    time.sleep(1)
    led.duty_cycle = 32768 #PWM al 50%
    time.sleep(1)
    led.duty_cycle = 16384 #PWM al 20%
    time.sleep(1)
    led.duty_cycle = 0
    time.sleep(1)