import machine
import time

# Define the GPIO pin connected to the LED
led_pin = 22  # You can change this to the GPIO pin you are using

# Create a PWM object
led_pwm = machine.PWM(machine.Pin(led_pin), freq=1000)

# Function to fade the LED in and out
def fade_led():
    for duty_cycle in range(1023, -1, -10):  # Fade in
        led_pwm.duty(duty_cycle)
        time.sleep_ms(20)
    
    for duty_cycle in range(0, 1024, 10):  # Fade out
        led_pwm.duty(duty_cycle)
        time.sleep_ms(20)

# Run the fading function in a loop
while True:
    fade_led()