I2C Receiving data.

Hi guys, 

I am trying to transmitt a data to slave address and trying to read it back. I can see the value in AC1 when i step through but not when I run the program and set a break point 

#define true 1

#include "msp430f2252.h"

volatile unsigned char receive = 0;

volatile unsigned char ready = 0;

volatile short ac1 = 0;

void main(void)

{

WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT

BCSCTL1 = CALBC1_1MHZ;

DCOCTL = CALDCO_1MHZ;

// Initialise i2c

P3SEL |= 0x06;                             // Assign I2C pins to USCI_B0

UCB0CTL1 |= UCSWRST;                       // Enable SW reset

UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master, synchronous mode

   UCB0CTL1 = UCSSEL_2 + UCSWRST;             // Use SMCLK, keep SW reset

   UCB0BR0 = 6;                             // fSCL = SMCLK/12 = ~100kHz

   UCB0BR1 = 0;

IE2 |= UCB0RXIE;                           // Enable RX interrupt

__delay_cycles(5);

    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts

   // Set the slave address

   UCB0I2CSA = 0x77; //01110111

   UCB0CTL1 &= ~UCSWRST;  // software reset disable. 

   // Start transmit condition

   UCB0CTL1 |= UCTR; // Enable Transmissoin mode

   UCB0CTL1 |= UCTXSTT; // generating start condition by setting UCTXSTT

   // Reading the calibration data

   while(!(IFG2 & UCB0TXIFG)); //   USCI_B0 RX buffer ready?

   UCB0TXBUF =  0xAC; // Transmit address to buffer

   // Send restart condition

   UCB0CTL1 &= ~UCTR; //Disable Transmission Mode

   UCB0CTL1 |= UCTXSTT; // gererate start condition 

   // Should receive two bytes from the slave

   //while(!(IFG2 & UCB0RXIFG));

ac1 = (short) (UCB0RXBUF << 8); //  16-bit 

//UCB0CTL1 |= UCTXSTP; 

//while(!(IFG2 & UCB0RXIFG));

ac1 = ac1 | UCB0RXBUF; 

// Respond with a NACK after receiving second byte

UCB0CTL1 |= UCTXSTP; // generate stop condition after the next acknowledge from the slave

I have a break Point here.  I shout get ac1 value in my watch window, when I run my program but I do not get anything. Can anyone suggest why I am unable to do that. If this is possible through interrupts please advise. Thanks. 

I am using Code Composer studio. Any help would be appreciatable. Thanks.