# import modules
########################################
from machine import Pin, PWM
from time import sleep

# set up pins
########################################
led_pwm=PWM(Pin(7))
duty_step = 129

frequency = 5000
led_pwm.freq (frequency)

#red = PWM(Pin(7))
#yellow = PWM(Pin(8))  
#green = PWM(Pin(9))  


# MAIN CODE
#########################################

# Set 1000 Hz frequency for all channels
#red.freq(1000)
#green.freq(1000)
#yellow.freq(1000)

while True:
    for duty_cycle in range(0, 65536, duty_step):
        led_pwm.duty_u16(duty_cycle)
        sleep(0.005)

    for duty_cycle in range(65536, 0, -duty_step):
        led_pwm.duty_u16(duty_cycle)
        sleep(0.005)