from machine import *
from utime import sleep_ms

l1 = PWM(Pin(5))
l2 = PWM(Pin(9))
l3 = PWM(Pin(13))
l1.freq(1000)
l2.freq(1000)
l3.freq(1000)

for br in range(0, 65535, 100):
    l1.duty_u16(br)
    sleep_ms(10)
    l2.duty_u16(br)
    sleep_ms(10)
    l3.duty_u16(br)
    sleep_ms(10)

l1.duty_u16(0)
l2.duty_u16(0)
l3.duty_u16(0)