#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#define F_CPU 16000000UL

// Define LCD control pins
#define RS PC4
#define E  PC5

// Define macros for setting and clearing bits
#define SET_BIT(port, bit) (port |= (1 << bit))
#define CLEAR_BIT(port, bit) (port &= ~(1 << bit))

void LCD_Command(unsigned char cmd) {
    // Send higher nibble
    PORTC = (PORTC & 0xF0) | ((cmd >> 4) & 0x0F);
    CLEAR_BIT(PORTC, RS);  // RS = 0 for command
    SET_BIT(PORTC, E);     // Enable high
    _delay_us(1);
    CLEAR_BIT(PORTC, E);   // Enable low

    _delay_us(200);        // Short delay

    // Send lower nibble
    PORTC = (PORTC & 0xF0) | (cmd & 0x0F);
    SET_BIT(PORTC, E);     // Enable high
    _delay_us(1);
    CLEAR_BIT(PORTC, E);   // Enable low

    _delay_ms(2);          // Command execution time
}

void LCD_Char(unsigned char data) {
    // Send higher nibble
    PORTC = (PORTC & 0xF0) | ((data >> 4) & 0x0F);
    SET_BIT(PORTC, RS);    // RS = 1 for data
    SET_BIT(PORTC, E);     // Enable high
    _delay_us(1);
    CLEAR_BIT(PORTC, E);   // Enable low

    _delay_us(200);        // Short delay

    // Send lower nibble
    PORTC = (PORTC & 0xF0) | (data & 0x0F);
    SET_BIT(PORTC, E);     // Enable high
    _delay_us(1);
    CLEAR_BIT(PORTC, E);   // Enable low

    _delay_ms(2);          // Data write time
}

void LCD_Init() {
    // Set control and data lines as output
    DDRC = 0xFF;

    _delay_ms(20);         // LCD power on delay

    // Initialization sequence in 4-bit mode
    LCD_Command(0x02);     // Initialize in 4-bit mode
    LCD_Command(0x28);     // 2 lines, 5x8 matrix
    LCD_Command(0x0C);     // Display on, cursor off
    LCD_Command(0x06);     // Increment cursor
    LCD_Command(0x01);     // Clear display
    _delay_ms(2);          // Clear display command delay
}

void LCD_String(char *str) {
    while (*str) {
        LCD_Char(*str++);
    }
}

void LCD_SetCursor(unsigned char row, unsigned char column) {
    unsigned char cmd;
    if (row == 0) {
        cmd = 0x80 + column;
    } else {
        cmd = 0xC0 + column;
    }
    LCD_Command(cmd);
}

void ADC_Init(){
	//DDRC = 0x00;               /* Make ADC port as input */
	ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<< ADPS0);   
            /* Enable ADC, with freq/128  */
	ADMUX = (1<<REFS0);           /* Vref: Avcc, ADC channel: 0 */
}

int ADC_Read(char channel)
{
	ADMUX = 0x40 | (channel & 0x07);          // set input channel to read
	ADCSRA |= (1<<ADSC);                               // Start ADC conversion
	while (!(ADCSRA & (1<<ADIF)));    	        // Wait until end of conversion by polling ADC interrupt flag 
	ADCSRA |= (1<<ADIF);                                // Clear interrupt flag 
  	_delay_ms(1);                                               //  Wait a little bit 
	return ADCW;                                                // Return ADC word 
}


void FloatToString(float value, char *buffer, int precision) {
    // Extract integer part
    int intPart = (int)value;
    // Extract fractional part
    int fracPart = (int)((value - intPart) * pow(10, precision));

    // Handle negative values
    if (value < 0) {
        intPart = -intPart;
        fracPart = -fracPart;
    }

    // Format into buffer
    sprintf(buffer, "%d.%*d", intPart, precision, fracPart);
}

int main()
{
  LCD_Init();            
  ADC_Init();

	char Voltage[10];
	float volt;

  while (1) {
		volt = (ADC_Read(0)*0.0488759);
		volt = (volt/10.00);
  	    	_delay_ms(10);
    

    LCD_SetCursor(0, 0);
    LCD_String("Voltage:");

    dtostrf(volt, 4, 2, Voltage);
    LCD_String(Voltage);

}}

/*
int main(void) {
    LCD_Init();            // Initialize LCD
    ADC_Init();            // Initialize ADC

    char buffer[32];       // Increase buffer size to 32 characters

    while (1) {
        int adc_value = ADC_Read(0); // Read ADC value from channel 0
        float voltage = adc_value * (5.0 / 1023.0); // Convert to voltage

        LCD_SetCursor(0, 0);   // Set cursor to first row, first column
        LCD_String("Voltage:");

        LCD_SetCursor(1, 0);   // Set cursor to second row, first column
        FloatToString(voltage, buffer, 2);
        strcat(buffer, " V");
        LCD_String(buffer);

        _delay_ms(100);       // Wait for a second

        LCD_Command(0x01);     // Clear display
        _delay_ms(2);          // Clear display command delay
    }

    return 0;
}*/