msp430g2553用I2C读取bq27541,读不出数据

附件是程序文件，用I2C通讯，I2c程序是TI官网推荐程序，软件调试OK，硬件调试的时候，读不出数据，IE2不能置位。以下是程序，附件是I2C程序文件，请大侠帮忙看看，谢谢！

#include "io430g2553.h"
#include "io430.h"
#include "F:\项目\程序编写\2016\lib\I2C_USCI\TI_USCI_I2C_master.h"
#include "bq27541.h"

#define _I2C_USCI


#define I2CSLAVEADDR           0x55           // 7-bit slave address
#define    uint    unsigned int
#define BUFFERSIZE             32           // # of bytes for Tx & Rx buffers


unsigned char TxData[BUFFERSIZE];           // Stores data bytes to be TX'd
unsigned char RxData[BUFFERSIZE];           // Stores data bytes that are RX'd
unsigned int  SOC;                          // Stores State of Charge
unsigned int transBytes2UnsignedInt(unsigned char msb, unsigned char lsb);
void MSP430_bq27541_read(unsigned char cmd, unsigned int bytes);

unsigned int transBytes2UnsignedInt(unsigned char msb, unsigned char lsb)
{
  unsigned int tmp;
 
  tmp = ((msb << 8) & 0xFF00);
  return ((unsigned int)(tmp + lsb) & 0x0000FFFF);  
}

void MSP430_bq27541_read(unsigned char cmd, unsigned int bytes)
{
  unsigned char tx[1];
  tx[0] = cmd;
  TI_USCI_I2CWrite(I2CSLAVEADDR, 1, 1, tx);
  TI_USCI_I2CRead(I2CSLAVEADDR, bytes, 0, RxData);
}

void main(void)
{
    WDTCTL = WDTPW +WDTHOLD;                  // Stop Watchdog Time
    BCSCTL1 = CALBC1_1MHZ;                    // Set DCO to 1 MHz
    DCOCTL = CALDCO_1MHZ;
    P1IES |= BIT0;                            // P1.0选择下降沿中断
    P1IE  |= BIT0;                            // 打开中断使能
    P2DIR |= BIT1+BIT2+BIT3+BIT4;             // 设置P2.1 ,2.2 ,2.3, 2.4 为输出状态
    P2OUT |= BIT1+ BIT2 + BIT3 + BIT4;        // 设置P2.1 ,2.2 ,2.3, 2.4 输出为高
    for(unsigned int i=0;i<65000;i++);                             // 延时
    P2OUT &= ~(BIT1+ BIT2 + BIT3 + BIT4);     // 设置P2.1 ,2.2 ,2.3, 2.4 输出为低
   while (1)
    {
            __enable_interrupt();
       TI_USCI_I2C_transmitinit(I2CSLAVEADDR,I2CCLOCKPRESCALER);
       while ( TI_USCI_I2C_notready() );
       MSP430_bq27541_read(bq27541CMD_SOC_LSB, 2);
       SOC = transBytes2UnsignedInt(RxData[1], RxData[0]);
       __bis_SR_register(SCG1+SCG0+CPUOFF + GIE);
       P2OUT &= ~(BIT1+ BIT2 + BIT3 + BIT4);
    }
}

#pragma vector = PORT1_VECTOR
__interrupt void  PORT1_ISR(void)
{
        if(P1IFG & 0x01)
      {
         for(unsigned int i=0;i<6000;i++);
         if(P1IFG & 0x01)
         {
            P1IFG ^= 0x01;
            __enable_interrupt();
            TI_USCI_I2C_transmitinit(I2CSLAVEADDR,I2CCLOCKPRESCALER);
            while ( TI_USCI_I2C_notready() );
            MSP430_bq27541_read(bq27541CMD_SOC_LSB, 2);
            SOC = transBytes2UnsignedInt(RxData[1], RxData[0]);
 //         SOC = 90;
          if (SOC == 0)
          {
            while(!(P1IN & BIT0))
            {
               P2OUT |= BIT1 + BIT4;
            }
          }
            
          else if (0<SOC <= 25)
          {    
             while (!(P1IN & BIT0))
             {
                P2OUT ^= BIT1;
                for(unsigned int i=0;i<35000;i++);
             }
          }
          else if(25<SOC && SOC<=55)
          {
             while (!(P1IN & BIT0))
             {
               P2OUT |= BIT1+ BIT2;
             }
          }
          else if(55<SOC && SOC<=85)
          {
             while (!(P1IN & BIT0))
             {
               P2OUT |= BIT1+ BIT2 + BIT3;
             }
          }
          else if(85<SOC)
          {
             while (!(P1IN & BIT0))
             {
                P2OUT |= BIT1+ BIT2 + BIT3 + BIT4;
             }
          }
        }
      }
  __bic_SR_register_on_exit(SCG1+SCG0+CPUOFF);
}