Problema con interrupcion, despertar el arduino y DS3234

Buenos días,

Tengo un RTC DS3234 configurado para hacer saltar una alarma cada 5 minutos y que despierte el arduino, el problema es que la interrupcion en el pin 2 parece que bloquea totalmente el arduino, de hecho si no lo duermo se bloquea totalmente cuando se activa,alguien puede ayudarme?

El código es:

// during an alarm the INT pin of the RTC is pulled low

#include <SPI.h>
#include "ds3234.h"
#include "Enerlib.h"

#define BUFF_MAX 256

const int cs = 8;              // chip select pin
uint8_t sleep_period = 5;       // the sleep interval in minutes between 2 consecutive alarms
Energy energy;

// how often to refresh the info on stdout (ms)
//unsigned long prev = 5000, interval = 5000;


void set_next_alarm(void)
{
    struct ts t;
    unsigned char wakeup_min;

    DS3234_get(cs, &t);

    // calculate the minute when the next alarm will be triggered
    wakeup_min = (t.min / sleep_period + 1) * sleep_period;
    if (wakeup_min > 59) {
        wakeup_min -= 60;
    }

    // flags define what calendar component to be checked against the current time in order
    // to trigger the alarm
    // A2M2 (minutes) (0 to enable, 1 to disable)
    // A2M3 (hour)    (0 to enable, 1 to disable) 
    // A2M4 (day)     (0 to enable, 1 to disable)
    // DY/DT          (dayofweek == 1/dayofmonth == 0)
    boolean flags[4] = { 0, 1, 1, 1 };

    // set Alarm2. only the minute is set since we ignore the hour and day component
    DS3234_set_a2(cs, wakeup_min, 0, 0, flags);

    // activate Alarm2
    DS3234_set_creg(cs, DS3234_INTCN | DS3234_A2IE);
}

void INT0_ISR(void)
{
  /*
  The WasSleeping function will return true if Arduino
  was sleeping before the IRQ. Subsequent calls to
  WasSleeping will return false until Arduino reenters
  in a low power state. The WasSleeping function should
  only be called in the ISR.
  */
  detachInterrupt(0);
  /*
  set_next_alarm();
  // clear a2 alarm flag and let INT go into hi-z
  DS3234_clear_a2f(cs);
  */
  Serial.println(" Entering interrupt 0");
  if (energy.WasSleeping())
  {
    /*
    Arduino was waked up by IRQ.
    
    If you shut down external peripherals before sleeping, you
    can reinitialize them here. Look on ATMega's datasheet for
    hardware limitations in the ISR when microcontroller just
    leave any low power state.
    */
    Serial.println("  Interrupt and was sleeping");
  }
  else
  {
    /*
    The IRQ happened in awake state.
    
    This code is for the "normal" ISR.
    */
    Serial.println("  Interrupt and was NOT sleeping");
  }
  Serial.println(" Exiting interrupt 0");
}

void setup()
{
    Serial.begin(9600);
    Serial.println("Entering setup");
    pinMode(2, INPUT);
    delay(5000);
    DS3234_init(cs, DS3234_INTCN);
    DS3234_clear_a2f(cs);
    set_next_alarm();
    attachInterrupt(0, INT0_ISR, LOW);
}

void loop()
{
  Serial.println("Entering loop");
  delay(5000);
  Serial.println("Powering down");
  energy.PowerDown();
  
  /*
  char buff[BUFF_MAX];
  struct ts t;
    
  DS3234_get(cs, &t);
  // display current time
  snprintf(buff, BUFF_MAX, "%d.%02d.%02d %02d:%02d:%02d", t.year, t.mon, t.mday, t.hour, t.min, t.sec);
  Serial.println(buff);
  */
  
}

Un saludo.

Conseguido, tiene la ventaja que se puede cambiar facilmente el tiempo que va a estar dormido, economizando así mucho la batería.

Por si a alguien le interesa el código:

#include <SPI.h>
#include "ds3234.h"
#include "Enerlib.h"

#define BUFF_MAX 256

const int cs = 8;              // chip select pin
uint8_t sleep_period = 5;      // the sleep interval in minutes between 2 consecutive alarms
Energy energy;
int time_interrupt=0;


void set_next_alarm(void)
{
  
    struct ts t;
    unsigned char wakeup_min;

    DS3234_get(cs, &t);

    // calculate the minute when the next alarm will be triggered
    wakeup_min = (t.min / sleep_period + 1) * sleep_period;
    if (wakeup_min > 59) {
        wakeup_min -= 60;
    }

    // flags define what calendar component to be checked against the current time in order
    // to trigger the alarm
    // A2M2 (minutes) (0 to enable, 1 to disable)
    // A2M3 (hour)    (0 to enable, 1 to disable) 
    // A2M4 (day)     (0 to enable, 1 to disable)
    // DY/DT          (dayofweek == 1/dayofmonth == 0)
    boolean flags[4] = { 0, 1, 1, 1 };

    // set Alarm2. only the minute is set since we ignore the hour and day component
    DS3234_set_a2(cs, wakeup_min, 0, 0, flags);

    // activate Alarm2
    DS3234_set_creg(cs, DS3234_INTCN | DS3234_A2IE);
    
}

void INT0_ISR(void)
{
  //detach interrupt and set time_interrupt=1
  //interrupt must be attached again
  detachInterrupt(0);
  time_interrupt=1;

}

void setup()
{
    Serial.begin(9600);
    Serial.println("Entering setup");
    pinMode(2, INPUT);
    delay(5000);
    DS3234_init(cs, DS3234_INTCN);
    DS3234_clear_a2f(cs);
    set_next_alarm();
    attachInterrupt(0, INT0_ISR, LOW);
}


void loop()
{
  if(time_interrupt==1){
    Serial.println(" time_interrupt==1");
    time_interrupt=0;
    
    // set next alarm
    set_next_alarm();
    // clear a2 alarm flag and let INT go into hi-z
    DS3234_clear_a2f(cs);
    //Attach interrupt again
    attachInterrupt(0, INT0_ISR, LOW);
    if (energy.WasSleeping())
      {
        Serial.println("  Interrupt and was sleeping");
      }
    else
      {
        /*
        The IRQ happened in awake state.
        This code is for the "normal" ISR.
        */
    Serial.println("  Interrupt and was NOT sleeping");
      }
  }
  Serial.println("Entering loop");
  delay(1000);
  /*
  //For debuf only
  char buff[BUFF_MAX];
  struct ts t;
    
  DS3234_get(cs, &t);
  // display current time
  snprintf(buff, BUFF_MAX, "%d.%02d.%02d %02d:%02d:%02d", t.year, t.mon, t.mday, t.hour, t.min, t.sec);
  Serial.println(buff);
  */
  Serial.println("Powering down");
  energy.PowerDown();

}