#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
//lcd connections
#define lcd_data PORTD
#define lcd_data_dir DDRD
#define lcd_ctrl PORTB
#define lcd_ctrl_dir DDRB
#define RS PB1
#define RW PB3
#define EN PB3
char column_y[2] = {0,64};
volatile uint16_t adc_result = 0;
//lcd initialzation (8 bit mode)
void lcd_init(void)
{
  lcd_ctrl_dir |= (1 << RW) | (1 << RS) | (1 << EN);
  _delay_ms(50);
  send_command(0x01);
  _delay_ms(2);
  send_command(0x38);
  _delay_ms(50);
  send_command(0x0E);
  _delay_ms(50);
}
//adc initialization
void adc_init(void)
{
  ADMUX |= (1 << REFS0);
  ADCSRA |= (1 << ADEN) | (1 << ADPS0) | (1 << ADPS1) | (1 << ADPS2) | (1 << ADIE);
  DIDR0 |= (1 << ADC0D);
  sei();
}
//start conversion
void start_conversion(void)
{
  ADCSRA |= (1 << ADSC);
}
//enable interrupt
ISR(ADC_vect)
{
  uint8_t low = ADCL;
  uint16_t tenbit = ADCH << 8 | low;
  adc_result = tenbit;
  start_conversion();
}
//send command
void send_command(unsigned char command)
{
  check_busy();
  lcd_data = command;
  lcd_ctrl &= ~((1 << RW) | (1 << RS));
  peekaboo();
  lcd_data = 0;
}
//send data
void send_data(unsigned char data)
{
  check_busy();
  lcd_data = data;
  lcd_ctrl &= ~(1 << RW);
  lcd_ctrl |= (1 << RS);
  peekaboo();
  lcd_data = 0;
}
//send byte
void send_byte(unsigned char data, int mode)
{
  if(mode == 1)
  {
    lcd_ctrl |= (1 << RS);
  }
  else
  {
    lcd_ctrl &= ~(1 << RS);
  }
  send_data(data);
  send_data(data << 4);
  _delay_ms(89);
}
//check busy
void check_busy(void)
{
  lcd_data_dir = 0;
  lcd_ctrl &= ~(1 << RS);
  lcd_ctrl |= (1 << RW);
  while(lcd_data >= 0x80)
  {
    peekaboo();
  }
  lcd_data_dir = 0xFF;
}
//peeking
void peekaboo(void)
{
  lcd_ctrl |= (1 << EN);
  asm volatile("nop");
  asm volatile("nop");
  lcd_ctrl &= ~(1 << EN);
}
//send interger
void send_integer(char lenght,int integervalue)
{
  char buffer[lenght];
  itoa(integervalue,buffer,10);
  set_cursor(0,0);
  for(int i=0;i<lenght;i++)
  {
    send_string("      ");
  }
  send_string(buffer);
}
//set cursor
void set_cursor(uint8_t x,uint8_t y)
{
  send_command(0x80 + x + column_y[y]);
}
//send string
void send_string(char *string)
{
  while(*string != '\0')
  {
    send_data(*string++);
  }
}
//send adc value
void send_adc(void)
{
  char buffer[16];
  itoa(adc_result,buffer,10);
  set_cursor(0,0);
  send_string(buffer);
}
//main function
int main(void)
{
  lcd_init();
  adc_init();
  start_conversion();
  while(1)
  {
    send_adc();
    _delay_ms(100);
  }
  return 0;
}