/* Registers a callback. 
Registers and enable a callback function which is implemented by the user. */
void dualtimer_register_callback(enum dualtimer_timer timer, dualtimer_callback_t fun)
/* Registers a callback. 
Registers and enable a callback function which is implemented by the user. */
void dualtimer_register_callback(enum dualtimer_timer timer, dualtimer_callback_t fun)
{
	if (timer == DUALTIMER_TIMER1) {
		dualtimer_callback_timer1 = fun;
	} else {
		dualtimer_callback_timer2 = fun;
	}
}