from machine import Pin,PWM
from time import sleep

frequency = 5000
led = PWM(Pin(5),frequency)

while True:
    for duty_cycle in range (0,1024,1):
        led.duty(duty_cycle)
        print(duty_cycle)
        sleep(0.009)
    for duty_cycle in range (1023,0,-1):
        led.duty(duty_cycle)
        print(duty_cycle)
        sleep(0.009)