from machine import Pin, PWM
import time

# Pin definition
led = Pin(15, Pin.OUT)  # Use GPIO15 (you can change this pin)

# PWM setup on the pin
pwm = PWM(led)
pwm.freq(1000)  # Frequency in Hz (e.g., 1 kHz)
pwm.duty_u16(0)  # Initially off (0% duty cycle)

# Variables for PWM control
fade_amount = 1000  # How much to increase/decrease brightness
brightness = 0      # Start with 0% brightness

while True:
    pwm.duty_u16(brightness)  # Set the PWM duty cycle (brightness)
    
    # Adjust brightness
    brightness += fade_amount
    
    # Reverse direction at the end points
    if brightness <= 0 or brightness >= 65535:
        fade_amount = -fade_amount
    
    # Wait before updating
    time.sleep(0.03)