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

uint8_t column[2] = {0,64};

#define F_CPU 16000000UL
//lcd connections
#define rs PC0
#define en PC1
#define D4 PC2
#define D5 PC3
#define D6 PC4
#define D7 PC5
//lcd functions
void lcd_init(void)
{
  DDRC |= (1 << rs) | (1 << en) | (1 << D4) | (1 << D5) | (1 << D6) | (1 << D7);
  _delay_ms(20);
  send_command(0x33);
  send_command(0x32);
  send_command(0x28);
  send_command(0x0C);
  send_command(0x06);
  send_command(0x01);
  _delay_ms(2);
}

void send_command(unsigned char command)
{
  PORTC = (PORTC & 0x03) | ((command & 0xF0) >> 2);
  PORTC &= ~(1 << rs);
  PORTC |= (1 << en);
  _delay_ms(1);
  PORTC &= ~(1 << en);
  _delay_ms(200);
  PORTC = (PORTC & 0x03) | ((command & 0x0F) << 2);
  PORTC |= (1 << en);
  _delay_ms(1);
  PORTC &= ~(1 << en);
  _delay_ms(2);
}

void send_data(unsigned char data)
{
  PORTC = (PORTC & 0x03) | ((data & 0xF0) >> 2);
  PORTC |= (1 << rs);
  PORTC |= (1 << en);
  _delay_ms(1);
  PORTC &= ~(1 << en);
  _delay_ms(200);
  PORTC = (PORTC & 0x03) | ((data & 0x0F) << 2);
  PORTC |= (1 << en);
  _delay_ms(1);
  PORTC &= ~(1 << en);
  _delay_ms(2);
}

void send_string(char *string)
{
  while(*string != '\0')
  {
    send_data(*string++);
  }
}

void set_cursor(uint8_t x,uint8_t y)
{
  send_command(0x80 + x + column[y]);
}
//chip functions
void reset(void)
{
  DDRD |= (1 << PD4);
  PORTD &= ~(1 << PD4);
  _delay_us(480);
  DDRD &= ~(1 << PD4);
  _delay_us(60);
  while(PIND & (1 << PD4));
  _delay_us(420);
}

void writebit(uint8_t data)
{
  DDRD |= (1 << PD4);
  PORTD &= ~(1 << PD4);
  _delay_us(1);
  if(data) PORTD |= (1 << PD4);
  _delay_us(60);
  DDRD &= ~(1 << PD4);
}

void writebyte(uint8_t byte)
{
  for(uint8_t i=0;i<8;i++)
  {
    writebit(byte & 0x01);
    byte >>= 1;
  }
}

uint8_t readbit(void)
{
  DDRD |= (1 << PD4);
  PORTD &= ~(1 << PD4);
  _delay_us(1);
  DDRD &= ~(1 << PD4);
  _delay_us(10);
  uint8_t bite = (PIND & (1 << PD4)) ? 1 : 0;
  _delay_us(50);
  return bite;
}

uint8_t readbyte(void)
{
  uint8_t bute;
  for(uint8_t i=0;i<8;i++)
  {
    bute |= (readbit() << i);
  }
  return bute;
}

float get_temp(void)
{
  uint8_t temp_msb,temp_lsb;
  uint8_t raw_temp;
  float temp_c;

  reset();
  writebyte(0xCC);
  writebyte(0x44);
  _delay_ms(750);

  reset();
  writebyte(0xCC);
  writebyte(0xBE);

  temp_lsb = readbyte();
  temp_msb = readbyte();
  raw_temp = temp_lsb << 8 | temp_msb;
  temp_c = raw_temp / 16.0;

  return temp_c;
}

int main(void)
{
  lcd_init();
  char buffer[16];

  while(1)
  {
    float temp = get_temp();
    set_cursor(0,0);
    send_string("temp = ");
    dtostrf(temp,5,1,buffer);
    send_string(buffer);
    send_string(" C");
    _delay_ms(1000);
  }
  return 0;
}