from machine import PWM , Pin
import time 

led = PWM(Pin(2),5000)
while True:
    for duty_cycle in range (0,1023,50):
        led.duty(duty_cycle)
        print(duty_cycle)
        time.sleep(0.1)

    for duty_cycle in range (1023,-1,-50):
        led.duty(duty_cycle)
        print(duty_cycle)
        time.sleep(0.5)