dspic30F2020 lee dos canales ADC

Estoy trabajando en dsPIC30F2020 para leer dos canales analógicos de forma secuencial en AN0 y AN1. Pero todo lo que obtuve es solo el valor de AN1, así que, ¿qué hay de malo en mis códigos a continuación? Muchas gracias por la ayuda

#define FCY 8000000UL // FCY = FOSC / 2

#include <xc.h>
#include <stdio.h>
#include <libpic30.h>
#include <p30F2020.h>
#include "config.h"

int main(void)
{
    int channel1Result;
    int channel3Result;

    /* Set up the ADC Module */

    ADCONbits.ADSIDL    = 0;        /* Operate in Idle Mode */
    ADCONbits.FORM      = 0;        /* Output in Integer Format */
    ADCONbits.EIE       = 1;        /* Enable Early Interrupt */
    ADCONbits.ORDER     = 0;        /* Even channel first */
    ADCONbits.SEQSAMP   = 1;        /* Sequential Sampling Enabled */
    ADCONbits.ADCS      = 5;        /* Clock Divider is set up for Fadc/14 */

    ADPCFG              = 0;        // all ANx analog input
    ADSTAT              = 0;        /* Clear the ADSTAT register */

    ADCPC0bits.TRGSRC0  = 1;        /* Use SW trigger */
    ADCPC0bits.IRQEN0   = 1;          /* Enable the interrupt   */
    ADCPC1bits.TRGSRC2  = 1;
    ADCPC1bits.IRQEN2   = 1;

    ADCONbits.ADON      = 1;        /* Start the ADC module */  

    /* Set up the Interrupts */

    IFS0bits.ADIF       = 0;        /* Clear AD Interrupt Flag */   
    IFS2bits.ADCP2IF    = 0;

    IPC2bits.ADIP       = 4;        /* Set ADC Interrupt Priority */

    IEC0bits.ADIE       = 1;        /* Enable the ADC Interrupt */
    IEC1bits.AC1IE      = 1;

    ADCPC0bits.SWTRG0   = 1;        /* Trigger the Conversion Pair 0 */ 
    ADCPC1bits.SWTRG2   = 1; 

    int a1;
    int a2;

    // enable UART communication
    U1BRG = 12; // baudrate
    U1MODEbits.UARTEN = 1; // enable UART

    PORTA = 0xffff; 
    TRISAbits.TRISA9 = 0; 

    while (1)
    {
        PORTAbits.RA9 = 1;
        while(ADCPC0bits.PEND0);    /* Wait for the 2nd conversion to
                                       complete */
        channel1Result  = ADCBUF1;  /* Read the result of the second
                                       conversion   */  
        while(ADCPC1bits.PEND2);
        channel3Result  = ADCBUF3;

        a1 = channel1Result;
        a2 = channel3Result;

        ADCPC0bits.SWTRG0   = 1;    /* Trigger another conversion */    
        ADCPC1bits.SWTRG2   = 1;

        printf("data 1 : ");
        printf("%d", a1);
        printf("\t data 2 : ");
        printf("%d", a2);
        printf("\n");

        __delay_ms(500);
    }
}

void __attribute__ ((interrupt, no_auto_psv)) _ADCInterrupt(void)
{
    /* AD Conversion complete early interrupt handler */

    int channel0Result;
    int channel2Result;

    IFS0bits.ADIF       = 0;        /* Clear ADC Interrupt Flag */
    IFS2bits.ADCP1IF    = 0;

    channel0Result      = ADCBUF0;  /* Get the conversion result */
    channel2Result      = ADCBUF2;

    ADSTATbits.P0RDY    = 0;        /* Clear the ADSTAT bits */ 
    ADSTATbits.P2RDY    = 0;
}