MSP430F5325: I want to select 2 input channels by adc12, but one channel is not work.

code:

void AdcInit(void)
{
    ADC12CTL0 = ADC12SHT02 + ADC12ON;         // Sampling time, ADC12 on
    ADC12CTL1 = ADC12SHP;                     // Use sampling timer
    ADC12MCTL0 = ADC12INCH_2;                  // select input channel 2
    ADC12MCTL1 = ADC12INCH_3 | ADC12EOS;      // select input channel 3
    ADC12IE = ADC12IE0;                       // Enable interrupt
    ADC12CTL0 |= ADC12ENC;
    P6SEL |= BIT2 | BIT3;                     // P6.0 ADC option select
}

#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
{
    uint16                      nTemp;

    switch(__even_in_range(ADC12IV,34))
    {
    case  0: break;                           // Vector  0:  No interrupt
    case  2: break;                           // Vector  2:  ADC overflow
    case  4: break;                           // Vector  4:  ADC timing overflow
    case  6:                                  // Vector  6:  ADC12IFG0
        nTemp                   = ADC12MEM0;
        TraceLog("ADC12MEM0 = %d\n", nTemp);

        nTemp                   = ADC12MEM1;
        TraceLog("ADC12MEM1 = %d\n", nTemp);

        __bic_SR_register_on_exit(LPM0_bits);   // Exit active CPU
        break;
    case  8:                                  // Vector  8:  ADC12IFG1
        break;
    default: break;
    }
}

p6.2 is successed, but P6,3 is failed ADC12MEM1is zero. but P6.3 voltage is 3.3V