Energia RTC Library for MSP430 http://blog.qscope.org/2012/05/22/bibliotheque-rtc-pour-le-msp430/

Example.ino

#include <sRTCsec.h>
#include <legacymsp430.h>
#include <TimerSerial.h>
 
// TimerSerial mySerial;
RealTimeClockSec myRTC;
 
  int ledState = LOW;
 
void setup() {
  pinMode(2, OUTPUT);
 
  // This is to close the serial output so you are able to upload a new sketch to the LaunchPad
  pinMode(5, INPUT_PULLUP),
  attachInterrupt(5,fin,LOW);
 
  Serial.begin(9600);
 
}
 
// The LED1 will blink each exact second and the time will be printed to the serial port
void loop() {
  if ((myRTC.RTC_sec % 2)==0 && ledState== HIGH) {
  ledState = LOW;
  dispserial(myRTC.RTC_hr,myRTC.RTC_min,myRTC.RTC_sec);
  digitalWrite(2, ledState);
  }
 
  if ((myRTC.RTC_sec % 2)==1 && ledState== LOW) {
  ledState = HIGH;
  dispserial(myRTC.RTC_hr,myRTC.RTC_min,myRTC.RTC_sec);
  digitalWrite(2, ledState);
  }
}
 
void fin() {
  Serial.end();
}


void dispserial(int r_hr,int r_min,int r_sec) {
  if (r_hr<10) Serial.print("0");
  Serial.print(r_hr, DEC);
  Serial.print(":");
  if (r_min<10) Serial.print("0");
  Serial.print(r_min, DEC);
  Serial.print(":");
  if (r_sec<10) Serial.print("0");
  Serial.println(r_sec, DEC);
}

interrupt(TIMER1_A0_VECTOR) Tic_Tac(void) {
    myRTC.Inc_sec();              // Update secondes
}

sRTCsec.cpp

/*
 sRTC.h - Library for adding simple RTC capabilities using MSP430 hardware
 By Yannick DEVOS (XV4Y) - 2012
 */
 
// include this library's description file
#include <sRTCsec.h>
#include <legacymsp430.h>
 
// Constructor /////////////////////////////////////////////////////////////////
 
RealTimeClockSec::RealTimeClockSec(void)
{
    RTC_sec = 0;
    RTC_min = 0;
    RTC_hr = 0;
 
    WDTCTL = WDTPW | WDTHOLD; // Kill watch-dog
 
    BCSCTL1 = DIVA_3;        // Clock = ACLK / 8
    BCSCTL3 |= (LFXT1S_0 | XCAP_3);        // Internal 12.5pF cap for 32KHz crystal
 
    TA1CCTL0 = CCIE;             //  CCR0 interupt activated
    TA1CCR0 = 4096-1;               // 4096 ticks of 32KHz XTal = 1 second => CCR0 counts N+1
    TA1CTL = TASSEL_1 | ID_3 | MC_1;  // Clock for TIMER 1 = ACLK, By 8 division, up front
 
}
 
// Methods /////////////////////////////////////////////////////////////////
 
void RealTimeClockSec::Inc_sec(void) {
    RTC_sec = RTC_sec + 1;            // Update seconds
    if (RTC_sec == 60) {
        RTC_sec=0;
        Inc_min();
    }
}
 
void RealTimeClockSec::Inc_min(void) {
    RTC_min = RTC_min + 1;            // Update minutes
    if (RTC_min == 60) {
        RTC_min=0;
        Inc_hr();
    }
}
 
void RealTimeClockSec::Inc_hr(void) {
    RTC_hr = RTC_hr + 1;              // Update hours
    if (RTC_hr == 24) {
        RTC_hr=0;
    }
}
 
void RealTimeClockSec::Set_Time(char hrs=0, char mins=0, char secs=0) {
    if ((hrs>=0 && hrs <24) && (mins>=0 && mins<60) && (secs>=0 && secs<60)) {
        RTC_hr = hrs;   // Set time to values given in parameters
        RTC_min = mins;
        RTC_sec = secs;
    }
}

sRTCsec.h

/*
 sRTC.h - Library for adding simple RTC capabilities using MSP430 hardware
 By Yannick DEVOS (XV4Y) - 2012
 
///////////////////////////////// How to use the lib
 
 * Create an instance of the object
 
 RealTimeClock myClock;
 
 * In order to have this RTC library working you should add this code to the end of your main program :
 
 interrupt(TIMER1_A0_VECTOR) Tic_Tac(void) {
    myClock.Inc_sec();            // Update secondes
 };
 
 * Enjoy the clock reading the RTC_sec, RTC_min, RTC_hr variables
 
 */
 
// ensure this library description is only included once
#ifndef RTCsec_h
#define RTCsec_h
 
// library interface description
class RealTimeClockSec
{
    // user-accessible "public" interface
public:
    RealTimeClockSec(void);
    void Set_Time(char hr, char mins, char secs);
    char RTC_sec; // This how you read the time, by reading the vars
    char RTC_min;
    char RTC_hr;
    void Inc_sec(void); // This methode should be invoked by an Interrupt call (see top of the file comment)
    // A few private methods
private:
    void Inc_min(void);
    void Inc_hr(void);
};
 
#endif