lpc2368 ADC 2,3 not working

void InitADC()
{
  PCONP   |= 1<<12; //set ADC power clock
  //ADC0-3 enabled
  PINSEL1 |= 0x55 << 14 ;    //0b01010101
  PINSEL1 &= ~(0xAA<<14);        //0b10101010
  AD0CR= 0x00200500  ;
}

void ADC_stopCnv (void) {
  AD0CR &= ~0x01000000;                          /* stop conversion  */
}

void read_adc()
{
  unsigned char adc_input;

  for (adc_input=0; adc_input<4; adc_input++)
  {
    AD0CR &= 0xFFFFFF00;
        AD0CR|=adc_input;

        delay_us(10);
        ADC_stopCnv();
    AD0CR |= (1<<24); //start
    delay_us(10);
        //x2=AD0GDR;
    while (!(AD0GDR & (1UL<<31)));
    //AnalogValues[adc_input] = (AD0GDR>>6 & 0x3FF);                                  //this line wasn't working properly so I used AD0DRx
        ADC_stopCnv();

        //send data to RS232 port
        if(adc_input==0)
        {
          AnalogValues[adc_input]=AD0DR0>>6;
          sendchar(0);
          sendchar(AnalogValues[adc_input]>>8);
          sendchar(AnalogValues[adc_input]);
          delay_ms(400);
        }
        else if(adc_input==1)
        {
          AnalogValues[adc_input]=AD0DR1>>6;
          sendchar(1);
          sendchar(AnalogValues[adc_input]>>8);
          sendchar(AnalogValues[adc_input]);
          delay_ms(400);
        }
        else if(adc_input==2)
        {
          AnalogValues[adc_input]=AD0DR2>>6;
          sendchar(2);
          sendchar(AnalogValues[adc_input]>>8);
          sendchar(AnalogValues[adc_input]);
          delay_ms(400);
        }
        else if(adc_input==3)
        {
          AnalogValues[adc_input]=AD0DR3>>6;
          sendchar(3);
          sendchar(AnalogValues[adc_input]>>8);
          sendchar(AnalogValues[adc_input]);
          delay_ms(400);
        }
  }

}