Fluctuation in ADC in PIC16F877

  void ADC_Init()
{
   ADCON0 = 0x81;  // ADON = 1, Channel A.0 select, Fosc/32 select
   ADCON1 = 0x8E;    // 0x8E,0xC0 port a as analog, right justified output
}    //original 0x8E


unsigned int ADC_Read(unsigned char channel)
{
  int i; 
  unsigned int avg_output=0,temp=0, ;
  if(channel > 7) return 0; 

  ADCON0 &= 0xC7;        // AND= RAZ channel selection
  ADCON0 |= channel<<3; // OR = Set  chanel selection
  Delay_ms(3);
  for(i=0;i<32;i++)
        {   
            GO_bit = 1;
            _asm NOP  //  allways one instruction after setting bit GO
            while(GO_bit);  // Wait until conversion gets over
        Delay_ms(2);
            temp=temp+(unsigned int) (ADRESH<<8) + ADRESL ;   // Store 10-bit output into a 16-bit variable
        Delay_ms(5);
            
        }
Delay_ms(5);
//temp=32736;   // to test =32*1023
avg_output=temp>>5;    // use SHIFT to divide by 32 to avoid use of maths.h
return(avg_output);
}

char CRam[6];  // pour affichage integer maxi= 65536

// in main()
......
 M1= ADC_Read(0);
 Lcd_Cmd(_LCD_SECOND_ROW );
 WordToStr(M1,CRam0); // attention le buffer CRam0  ne doit pas etre trop long !!   sinon deborde du LCD...
 Lcd_Out_CP(CRam0);  
.......