const int led = 13;
after i've upload this sketch, the L-LED turns off. Or if i put a LED in Pin 13 and Ground, then the onboard L-LED turns off too.
look at this guy
he turns on the L-LED on by a button in labview.First the L-LED is off. Then when he press the boolean button the L-LED lights on.
And when he press again the button, the L-LED turns off.
But on my board the L-LED is already on, although i don't press the boolean button. That's the error.