from time import sleep
from machine import Pin

led = Pin(0, Pin.OUT)
button = Pin(28, Pin.IN, Pin.PULL_DOWN)
led_state = False

def ButtonIRQHandler (pin):
    global led_state
    if led_state == True:
        led_state = False
    else:
        led_state = True

button.irq (trigger = machine.Pin.IRQ_RISING, handler = ButtonIRQHandler)

while True:
    led.value (led_state)