/*
#define F_CPU 16000000UL
#include<avr/io.h>
#include<util/delay.h>
#include <stdio.h>
#include <stdlib.h>

#define LCD_Dir DDRB
#define LCD_Port PORTB
#define RS PB0
#define EN PB1

volatile uint8_t button = 0;

//Sending a Command to LCD
void LCD_Command(unsigned char cmnd )
{
  LCD_Port=(LCD_Port & 0x0F) | (cmnd & 0xF0); 
  LCD_Port &= ~ (1<<RS); 
  LCD_Port |= (1<<EN); 
  _delay_us(1);
  LCD_Port &= ~ (1<<EN);
  _delay_us(200);
  LCD_Port = (LCD_Port & 0x0F) | (cmnd << 4); 
  LCD_Port |= (1<<EN);
  _delay_us(1);
  LCD_Port &= ~ (1<<EN);
  _delay_ms(2);
}

//Data Writting on LCD
void LCD_Char( unsigned char data )
{
  LCD_Port = (LCD_Port & 0x0F)|(data & 0xF0);
  LCD_Port |= (1<<RS); 
  LCD_Port|= (1<<EN);
  _delay_us(1);
  LCD_Port &= ~ (1<<EN);
  _delay_us(200);
  LCD_Port = (LCD_Port & 0x0F)|(data << 4); 
  LCD_Port |= (1<<EN);
  _delay_us(1);
  LCD_Port &= ~ (1<<EN);
  _delay_ms(2);
}

//LCD Initialization for 4-bit Mode
void LCD_Init (void) 
{
  LCD_Dir = 0xFF; 
  _delay_ms(20); 
  LCD_Command(0x33);
  LCD_Command(0x32); 
  LCD_Command(0x28); 
  LCD_Command(0x0c); 
  LCD_Command(0x06); 
  LCD_Command(0x01); 
  _delay_ms(2);
}

//Display a String on LCD
void LCD_String (char *str) 
{
  int i;
  for(i=0;str[i]!=0;i++) 
  {
    LCD_Char (str[i]);
  }
}

//Cleaning LCD
void LCD_Clear()
{
  LCD_Command (0x01); 
  _delay_ms(2);
  LCD_Command (0x80); 
}

void Timer1_Init()
{
  //TCNT1= 59286;
  //TCNT1= 63973;
  TCNT1= 61286;
  TCCR1A = 0x00;
  TCCR1B |= (1<<CS02);
  TIFR1 |= (1<<TOV1);
  
  while(((TIFR1)&(1<<TOV1))==0);
  TCCR1B = 0x00;
  TCCR1A = 0x00;
  TIFR1 = 0x01;
}

void INT3_init()
{
  cli();

  DDRD &= ~(1<<PD3);
  PORTD |= (1<<PD3);

  EICRA |= (1<<ISC31);
  EICRA &= ~(1<<ISC30);
  EIMSK |= (1<<INT3); 

  sei();
}

ISR(INT3_VECT, ISR_NOBLOCK)
{
  EIMSK &= ~(1<<INT3);
  button = (button == 0) ? 1: 0;
  EIFR |= (1<<INTF3);
  EIMSK |= (1<<INT3);
}

int main()
{
  LCD_Init();
  cli();
  INT3_init();
  sei();

  char TIME[10];
  float time;

  while(1)
  {
    if(button == 1)
    {
      while(button == 1)
      {
        Timer1_Init();
        time += 0.1;
        dtostrf(time, 5, 1, TIME);
        LCD_Clear();
        LCD_Command(0x80);
        LCD_String(TIME);
        LCD_Command(0xC0);
        _delay_ms(500);
      }
    }
    if(button == 0)
    {
      while(button == 0)
      {
        dtostrf(time, 5, 1, TIME);
        LCD_Clear();
        LCD_Command(0x80);
        LCD_String(TIME);
        LCD_Command(0xC0);
        _delay_ms(500);
      }
    }
  }
}
*/

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

#define LCD_Dir DDRB        
#define LCD_Port PORTB  
#define RS PB0             
#define EN PB1              
//uint8_t count=0;
volatile uint8_t button=0;
char Time[10];
float time = 0;
void LCD_Command(unsigned char cmnd) {
    LCD_Port = (LCD_Port & 0x0F) | (cmnd & 0xF0);
    LCD_Port &= ~(1<<RS);
    LCD_Port |= (1<<EN);
    _delay_us(1);
    LCD_Port &= ~(1<<EN);

    _delay_us(200); /* LCD Power ON delay always >15ms */

    LCD_Port = (LCD_Port & 0x0F) | (cmnd << 4);  /* sending lower nibble */
    LCD_Port |= (1<<EN);
    _delay_us(1);
    LCD_Port &= ~(1<<EN);
    _delay_ms(2);
}

void LCD_Char(unsigned char data) {
    LCD_Port = (LCD_Port & 0x0F) | (data & 0xF0); /* sending upper nibble */
    LCD_Port |= (1<<RS);        /* RS=1, data reg. */
    LCD_Port |= (1<<EN);
    _delay_us(1);
    LCD_Port &= ~(1<<EN);

    _delay_us(1);

    LCD_Port = (LCD_Port & 0x0F) | (data << 4); /* sending lower nibble */
    LCD_Port |= (1<<EN);
    _delay_us(1);
    LCD_Port &= ~(1<<EN);
    _delay_ms(2);
}

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

void LCD_Init(void) {
    LCD_Dir = 0xFF;             /* Make LCD command port direction as o/p */
    _delay_ms(20);              /* LCD Power ON delay always >15ms */

    LCD_Command(0x33);
    LCD_Command(0x32);          /* send for 4 bit initialization of LCD  */
    LCD_Command(0x28);          /* Use 2 line and initialize 5*7 matrix in (4-bit mode)*/
    LCD_Command(0x0c);          /* Display on cursor off*/
    LCD_Command(0x06);          /* Increment cursor (shift cursor to right)*/
    LCD_Command(0x01);          /* Clear display screen*/
    _delay_ms(2);
    LCD_Command(0x80);          /* Cursor 1st row 0th position */
}

// External Interrupt
void port_init(void) {
    // Declare PIN for external interrupt:
    DDRE &= ~(1 << PD3); // Set PE5 as input
    PORTE |= (1 << PD3); // Enable pull-up resistor on PE5
    // External Interrupt 5, falling edge triggered
    EICRA |= (1 << ISC31); // Set ISC51 for falling edge detection
    EICRA &= ~(1 << ISC30); // Clear ISC50 for falling edge detection
    EIMSK |= (1 << INT3); // Enable External Interrupt 5
}

void init_devices(void)
{
  cli(); // disable all interrupts
  port_init();
  sei(); // re-enable interrupts
}
void Timer1_Delay(void);
void Timer1_Delay(int milisecond);
void Timer1_Delay()
{
  TCNT1=63974;//from calculation
  TCCR1A = 0x00;
  TCCR1B = (1<<CS00)|(1<<CS02);//prescalar=1024
  while(((TIFR1)&(1<<TOV1))==0); //wait for TF0 to roll over
    TCCR1B=0;
    TCCR1A=0;
    TIFR1= 0x01;
}
void Timer1_Delay(int milisecond)
{
  int count= ((65535*(4194-(milisecond))/4194));
  TCNT1=count;
  TCCR1A=0x00;
  TCCR1B= (1<<CS00)|(1<<CS02);
  while(((TIFR1)&(1<<TOV1))==0);
    TCCR1B=0;
    TCCR1A=0;
    TIFR1=1;
}
ISR(INT3_vect, ISR_NOBLOCK) {
    EIMSK &= ~(1 << INT3); // External Interrupt 5 Disable
    button = (button==0) ? 1: 0;
    EIFR |= (1 << INTF3); // Clear External Interrupt Flag
    EIMSK |= (1 << INT3); // External Interrupt 5 enable
}
int main() {

    LCD_Init();
    cli(); // disable all interrupts
    port_init();
    sei(); // re-enable interrupts
    while (1) {
      if(button==1) {
            LCD_Command(0x01); // Clear the LCD
            LCD_String("Timing Started: ");
            while(button==1)
            {
              Timer1_Delay(100);
              time = time + 0.1;
              dtostrf(time, 5, 2, Time);
              LCD_Command(0xC0);
              LCD_String(Time);
            }
        } 
        else if(button==0) {
          LCD_Command(0x01); // Clear the LCD
          LCD_String("Timing Stopped: ");
            while(button==0)
            {
              dtostrf(time, 5, 2, Time);
              LCD_Command(0xC0);//clear and write on 2nd line
              LCD_String(Time);
            }
        }   
    }
    return 0;
}