adc mess falsch

#include <avr/io.h>

#include <inttypes.h>

#include <stdlib.h>

#include <avr/interrupt.h>

#include <string.h>

#include "uart.h"

#include "adc.h"

// define global variables

int ADIteiler=0;

char s[20];

void Adc_portinit(void) //Initialsierung

{  

  DDRF = 0x00;  // define as Input

  PORTF = 0x00;    //enables Pull-Up on PC0

}//end Adc_portinit()

unsigned int ADC_Read(unsigned char Mux_channel) 

{

  uint8_t i;

  uint16_t result = 0;

  ADCSRA = (1<<ADEN);         //enables the ADC

  ADCSRA |= (1<<ADPS2) | (1<<ADPS0);   //determine the division factor between the XTAL frequency and the input clock to the ADC. 

                    //ADC division factor auf 8 setzen Tmin = 20 , Tmax = 80 systemt clock F_CPU = 4000000

  ADMUX = Mux_channel;  // Analog Channel Selection  

  ADMUX |= (1<<REFS0) | (1<<REFS1);//int. REF Voltage Reference Selection

  ADMUX |= (0<<ADLAR);  //the result is right adjusted

  ADCSRA |= (1<<ADSC);// The ADC initialization and made a dummy readout

  while(ADCSRA & (1<<ADSC));

  result = ADCW;      // ADCW must be read once

    result = 0;// otherwise the result of the next transformation is not taken over

  //Now reads 4 times the similar tension and selected channel channel 

  //and then calculate the average value divided by 4. Because the ADC measeres 0..1023,

  //and the Port however can only 0..255 show

  for(i=0; i<4; i++) 

  {    

    ADCSRA |= (1<<ADSC);  //a single conversion

    while(ADCSRA & (1<<ADSC));//waiting on conversion closing 

    result += ADCW;

  }

  ADCSRA &= (0<<ADEN);          // ADC reanables

  result /= 4;

  return result;

}//end int ADC_Read() 

void Send_adcValue(char* ADC_Value, int Length)

{

  Adc_portinit();

  if(strcmp(ADC_Value, "adc") == 0)

  {

    uart0_puts ("\r\n");

      uart0_puts ("Messwert: ");

        unsigned int result = ADC_Read(0);// Reading the Analog on PinF 0,

                      // Thus ADF0. In result steht das Ergebnis.    

    utoa( result, s, 10 );   // convert HEX-Zahlen in Ascii

    uart0_puts( s );

  }

  else

  uart0_puts("error");

}//Send_adcValue()