Atmega328 Analog-to-Digital Converter - arduino

Question

I am working on understanding ADC with an arduino and a LCD shield that has buttons. I like to work in Atmel Studio and work to write my own libraries through research and the datasheet. My goal is to write the ADC value to the screen. If I write an Arduino Sketch with the analogRead() function it works, but I can not get it to read anything on the LCDw with my Atmel Studio program. The LCD does work as I can write other information on the LCD. My program is below. Any ideas would really help. Thanks!!!
Analog Header
#include<util/delay.h>
void adc_init(void)
{
ADMUX = (1<<REFS0); //select AVCC as reference
ADCSRA = (1<<ADEN) | 7; //enable (ADEN) and prescale = 128 (16MHz/128 = 125kHz)
}
int readAdc(char chan)
{
ADMUX = (1<<REFS0) | (chan & 0x0f); //select ref (REFS0) and channel
ADCSRA |= (1<<ADSC); //start the conversion
while (ADCSRA & (1<<ADSC)); //wait for end of conversion
return ADC; //Return 16 Bit Reading Register
}
Main Program
#ifndef F_CPU
#define F_CPU 16000000UL // 16 MHz clock speed
#endif
#define D4 eS_PORTD4
#define D5 eS_PORTD5
#define D6 eS_PORTD6
#define D7 eS_PORTD7
#define RS eS_PORTB0
#define EN eS_PORTB1
#include <avr/io.h>
#include <util/delay.h>
#include <stdio.h>
#include "lcd328.h"
#include "myHeader328.h"
/*--------------------------------------------------------
-- initScreen() initializes the screen
--------------------------------------------------------*/
void initScreen()
{
Lcd4_Init(); //Initialize Screen
Lcd4_Clear(); //Clear Screen
Lcd4_Set_Cursor(1,0);
Lcd4_Write_String("Count:0");
}
/*--------------------------------------------------------
-- refreshScreen() refreshed the screen
--------------------------------------------------------*/
void refreshScreen(int count2)
{
char countStr[5];
sprintf(countStr, "%i", count2);
Lcd4_Set_Cursor(1,6);
Lcd4_Write_String(countStr);
_delay_ms(50);
}
/*--------------------------------------------------------
-- main()
--------------------------------------------------------*/
int main(void)
{
DDRD = 0xFF;
DDRB = 0xFF;
DDRC = 0x00;
initScreen();
PORTB = PORTB | (1<<PORTB2); //Turn on backlight
int adcOut = 4;
while(1)
{
adcOut = readAdc(0);
refreshScreen(adcOut);
_delay_ms(500);
}
}

Answer 1

You had to call adc_init() in your main loop.
/*--------------------------------------------------------
-- main()
--------------------------------------------------------*/
int main(void)
{
DDRD = 0xFF;
DDRB = 0xFF;
DDRC = 0x00;
initScreen();
adc_init(); //!!!!!
PORTB = PORTB | (1<<PORTB2); //Turn on backlight
int adcOut = 4;
while(1)
{
adcOut = readAdc(0);
refreshScreen(adcOut);
_delay_ms(500);
}
}