Interrupt löst nicht aus.

void humidity_timer_init(){

   pmic_init(); 

   sysclk_init(); 

   volatile void *tc = &HUMIDITY_TIMER; //Adress

          tc_enable(tc); //Enable timer/counter 

   tc_write_period(tc, 100); //This will specify the TOP value of the counter. The timer will overflow and reset when this value is reached.

   tc_set_overflow_interrupt_callback(tc, LED_tester); //Set the callback function for overflow interrupt

   tc_set_overflow_interrupt_level(tc, TC_INT_LVL_HI ); //Set the overflow interrupt level

   tc_write_clock_source(tc, HUMIDITY_COUNTER_CLKSEL  ); //Set the clock source

}

void LED_tester(){

  ioport_set_pin_dir(D2, IOPORT_DIR_OUTPUT);

  ioport_set_pin_level(D2, true);

  ioport_toggle_pin_level(D2);  //Turn LED D2 On

}