from machine import PMW, Pin
from utime import sleep
rojo=PWM(Pin(12))
amarillo=PWM(Pin(13))
rojo.freq(1000)
amarillo.freq(1000)

while(True):
    for i in range 65535:
        rojo.duty_u16(i)
        amarillo.duty_u16(i)
        sleep(0.1)