Re: External RTC to wake Arduino up on interrupt

my code crash my adafruit feather… why ?

HELP PLEASE

#include <DS3232RTC.h>    //http://github.com/JChristensen/DS3232RTC
#include <Time.h>         //http://www.arduino.cc/playground/Code/Time  
#include <Wire.h>         //http://arduino.cc/en/Reference/Wire (included with Arduino IDE)
#include "LowPower.h"

const int wakeUpPin = 1;


void wakeUp()
{
        digitalClockDisplay();  
    //detect alarm:
    if ( RTC.alarm(ALARM_1) ) {
      Serial.println("alarm");
    }
}

void setup(void)
{
    Serial.begin(9600);
    setSyncProvider(RTC.get);   // the function to get the time from the RTC
    if(timeStatus() != timeSet) 
        Serial.println("Unable to sync with the RTC");
    else
        Serial.println("RTC has set the system time");  

   //set alarm:
   RTC.setAlarm(ALM1_MATCH_SECONDS, 5, 0, 0, 0);
   RTC.alarmInterrupt(ALARM_1, true);
   RTC.alarmInterrupt(ALARM_2, false);
   RTC.squareWave(SQWAVE_NONE);    //no square wave

   // Configure wake up pin as input.
   // This will consumes few uA of current.
    pinMode(wakeUpPin, INPUT_PULLUP); 
}

void loop(void)
{
   // Allow wake up pin to trigger interrupt on low.
    attachInterrupt(3, wakeUp, FALLING);
    // Enter power down state with ADC and BOD module disabled.
    // Wake up when wake up pin is low.
    LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF); 
    
    // Disable external pin interrupt on wake up pin.
    detachInterrupt(3); 
  
}

void digitalClockDisplay(void)
{
    // digital clock display of the time
    Serial.print(hour());
    printDigits(minute());
    printDigits(second());
    Serial.print(' ');
    Serial.print(day());
    Serial.print(' ');
    Serial.print(month());
    Serial.print(' ');
    Serial.print(year()); 
    Serial.println(); 
}

void printDigits(int digits)
{
    // utility function for digital clock display: prints preceding colon and leading 0
    Serial.print(':');
    if(digits < 10)
        Serial.print('0');
    Serial.print(digits);
}

This looks like a new question so I have split if off from the old one for you.

OK thanks,

Problem solved... i need some delay here:

delay(1000);
LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF); 
delay(1000);

I am glad that you solved your problem but delay(1000) TWICE is a long time in the Arduino world.