from machine import Pin
from time import ticks_ms

led = Pin(25, Pin.OUT)
led_state = 0  
previous_time = ticks_ms()

while True:
    current_time = ticks_ms()

    if current_time - previous_time >= 1000:
        if led_state == 0:
            led.value(1)   
            led_state = 1
        else:
            led.value(0)   
            led_state = 0

        previous_time = current_time