# Import the necessary libraries to enable 
# communication between the code and the 
# sketch on the board.
import board
import digitalio
import pwmio
from time import sleep

# Initialize the PWM for each LED to represent 
# an analog output.

led0 = pwmio.PWMOut(board.D0, duty_cycle=0, frequency=5000)
led1 = pwmio.PWMOut(board.D6, duty_cycle=0, frequency=5000)
led2 = pwmio.PWMOut(board.D7, duty_cycle=0, frequency=5000)

# Declare the button as an output
button = digitalio.DigitalInOut(board.D1)
button.direction = digitalio.Direction.OUTPUT

while True:
    
    # Initialize a temporary variable 
    # to control the pwm
    i = 0
    
    # The LEDs are initialized in the 
    # "off" state.
    led0.duty_cycle = 0
    led1.duty_cycle = 0
    led2.duty_cycle = 0
    sleep(0.1)
    
    # It will execute while the button is pressed 
    # and the temporary variable won't exceed the 
    # maximum value of the PWM, which in this case 
    # is 65535
    while button.value == True and i < 65535:
        
        # Assign the duty cycle to the temporary 
        # variable and increment it by 500, so the 
        # LEDs are turned on progressively.
        led0.duty_cycle = i
        led1.duty_cycle = i
        led2.duty_cycle = i
        i += 500
        sleep(0.05)