Numeric Voltmeter with Lcd Display (help)

/*****************************************************
This program was produced by the
CodeWizardAVR V1.24.7d Professional
Automatic Program Generator
© Copyright 1998-2005 Pavel Haiduc, HP InfoTech s.r.l.
[url]http://www.hpinfotech.com[/url]
e-mail:office@hpinfotech.com


Chip type           : ATmega16
Program type        : Application
Clock frequency     : 13.500000 MHz
Memory model        : Small
External SRAM size  : 0
Data Stack size     : 256
*****************************************************/

#include <mega16.h>
#include<stdio.h>
#include<delay.h>
#include<math.h>
// Alphanumeric LCD Module functions
#asm
  .equ __lcd_port=0x15;PORTC
#endasm
#include <lcd.h>
#define ADC_VREF_TYPE 0xC0

char lcd_buffer[33];
// Read the AD conversion result
unsigned int read_adc(unsigned char adc_input)
{  

ADMUX=adc_input|ADC_VREF_TYPE;
// Start the AD conversion
ADCSRA|=0x40;
// Wait for the AD conversion to complete
while ((ADCSRA & 0x10)==0);
ADCSRA|=0x10;
return ADCW;
}

// Declare your global variables here


void main(void)
{
float adc,volts;
//#asm("cli")


PORTA=0x20;
DDRA=0x20;

PORTB=0x00;
DDRB=0x00;

PORTC=0x00;
DDRC=0x00;  

PORTD=0x00;
DDRD=0x40;


// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;
// ADC initialization
// ADC Clock frequency: 105.469 kHz
// ADC Voltage Reference: Int., cap. on AREF
// ADC Auto Trigger Source: None
ADMUX=ADC_VREF_TYPE;
ADCSRA=0x87;
delay_ms(22);
// LCD module initialization
lcd_init(16);
 
 //lcd_gotoxy(0,1);
 //lcd_putsf("    [0-20V]    ");
 
while (1)   {  
     
      adc = read_adc(1);
      if (adc>830)
      { PORTD.6=1;
     lcd_gotoxy(0,1);
     lcd_putsf("Schimbati scala");
     delay_ms(500);
     lcd_clear();
      }
     else  
       PORTD.6=0;
      if(PINA.5==1){
            volts = (((adc *2.56)/1024)*10);
      }
       else  
              volts = (((adc *2.56)/1024));
     lcd_gotoxy(0,0);
     sprintf(lcd_buffer," Volts = %3.3fV ",volts);
     lcd_clear();
     lcd_puts(lcd_buffer);
     delay_ms(100);
       
     
}    

   }