problem anag. input pic16f690

[teragiga]

Hi
I am using a pic16f690, mplab and hitech compiler for a program in C.
Practically I have an input voltage value (coming from a light to voltage converter or even from other sources of tension), connected to RA0/AN0, and PORTC connected to a 7segments display and another 7segments display connected to PORTB and the last to output of PORTA.
What I need to do is to visualize the input voltage on the 2 display.
I am perfectly capable to use the 2 display to visualize the values I want on them but not the input voltage value.
(if I send void set7segB(5); then I see a 5).

The register of the ADC input in the 16f690 is based on 10 bits( either 2 on ADRESH and 8 on ADRESL, or the other way around).

Idependently from the input (even if I connect 5V or 2V direct to AN0 from a supplier) I see on the display alway two "8". Where is the mistake ?
I am using an adpted version of the Gooligum Electronics tutorial.
Please Help me I have no idea how to debug this. Cheers

Code:

 #include 
 __CONFIG(MCLREN & UNPROTECT & WDTDIS  & INTIO);
 
void set7segC(char digit);      // display digit on 7-segment display
 void set7segB(char digit);           // display digit on 7-segment display
 
 void main()
 {
     unsigned int    adc_dec;        // scaled ADC output (0-99)
     
     // configure ports
     TRISA = 0b11001011;
     ANSEL = 0b00000001;
     ANSELH = 0b00000001; 
     TRISB = 0b00000000;          // configure PORTB as outputs
     TRISC = 0b00000000;          // configure PORTC as outputs
     CM1CON0 = 0;                    // disable comparator 1 (RB0, RB1, RB2 usable)
     CM2CON0 = 0;                    // disable comparator 2 (RC0, RC1, RC4 usable)
     VRCON = 0;                      // disable CVref (RC2 usable)
     // configure ADC     
     ADCON0 = 0b10000011;       
              //1------             Right justified
              //-0------            VDD
              //--0000--            Set AN0 as the input
              //-------11             turn ADC on (ADON = 1)
     ADCON1 = 0b00110000;
 
     // Main loop
     for (;;)
     {
         // sample input
         GODONE = 1;             // start conversion
         while (GODONE);          // wait until done
         
         // scale result to 0-99
         adc_dec = (ADRESL + (ADRESH << 8)) * 99/1024;
         set7segC(adc_dec%10);    // output ones digit of result on segment bus 
         set7segB(adc_dec/10);    // output tens digit of result on segment bus 
 
     }      
}
 
 
 /***** FUNCTIONS *****/
 void set7segC(char digit)
 {
     // Lookup pattern table for 7-segment display on ports B and C
     const char pat7seg[10] = 
        {
         0b0111111,  // 0
         0b0011000,  // 1
         0b1110110,  // 2
         0b1111100,  // 3
         0b1011001,  // 4
         0b1101101,  // 5
         0b1101111,  // 6
         0b0111000,  // 7
         0b1111111,  // 8
         0b1111101   // 9
        };
     
     PORTC = pat7seg[digit] ;
 } 

 void set7segB(char digit)
 {
     // Lookup pattern table for 7-segment display on ports B and C
     const char pat7seg[10] = 
        {
         0b0111111,  // 0
         0b0011000,  // 1
         0b1110110,  // 2
         0b1111100,  // 3
         0b1011001,  // 4
         0b1101101,  // 5
         0b1101111,  // 6
         0b0111000,  // 7
         0b1111111,  // 8
         0b1111101   // 9
        };
     
     PORTB = pat7seg[digit] ;
     PORTA = pat7seg[digit]  & 1100000;
 }