AC voltage measurement using pic microcontroller

//========= Main loop ==============
CRLF();
do
  { 
         
 j=0;n1=0;
  PIR1bits.TMR1IF=0;      // raz flag interrupt
  WriteTimer1(15537);    // 19,99mS
  T1CONbits.TMR1ON=1; 
      while(PIR1bits.TMR1IF==0)
      {
         ADCON0=1;   // ADON=1 et choix de canal 
         ADCON0bits.ADON=1; //GO
         n1++;
         Delay10TCYx(1); 
         ConvertADC(); // Start conversion
          while( BusyADC() );
         Table_sinusoide[j] = ReadADC(); 
       j++;
        }
       T1CONbits.TMR1ON=0; 
       PIR1bits.TMR1IF=0; 
      Put_RS('N');
     Put_RS('=');
       Write_Word_(n1,0);
       CRLF(); 
       mini=1024;
       maxi=0;
       for(j=0;j<n1;j++)
       {
        M=Table_sinusoide[j];
        if (M<mini) mini=M;
        if(M>maxi)maxi=M;
        Drapeaux.Fill=1;
        Write_Word_(M,0);
        Drapeaux.Fill=0;
        Put_RS(';'); // separateur de champs  
        k=1+ (j & 0x0003);
        LCD_Erase_Line(k);    
        k=sprintf(txt,"%04d ",M);
        LCD_puts(txt);
        Tempo(10000L);
       } 
       CRLF();
       LCD_Erase_Line(4); 
       ecart=maxi-mini;
       k=fprintf(_H_USART,"Maxi=%04d  Mini=%04d  Peak2Peak=%04d \n",maxi,mini,ecart);
       k=sprintf(txt, "Maxi=%04d  Mini=%04d",maxi,mini);
       LCD_Erase_Line(1);    
       LCD_puts(txt);
       k=sprintf(txt, "Ecart pk2pk =%04d",ecart);
       LCD_Erase_Line(2);    
       LCD_puts(txt);  
       // 928 is the nb of point between maxi-mini of sinusoide for
       // a voltage input of 1,6V efficae + 2,5V DC as offset
       Voltage=(float)ecart*235.0/928;
       print_flt(Voltage,1,0); // on RS232
       fltToa (Voltage, txt,2);
       LCD_Erase_Line(3);    
       LCD_puts(txt);
        
  Tempo(500000L);
 CRLF();
  }
while(1);  
 
}