import machine
import time

led_onboard = machine.Pin("LED", machine.Pin.OUT)
Led_external = machine.Pin(15, machine.Pin.OUT)

led_onboard.value(1)
Led_external.value(0)
time.sleep(1)

while True:
    led_onboard.toggle()
    Led_external.toggle()
    time.sleep(1)
    led_onboard.toggle()
    Led_external.toggle()
    time.sleep(1)