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

#define HD44780_CLEAR 0x01
#define HD44780_HOME 0x02
#define HD44780_ENTRY_MODE 0x04
#define HD44780_EM_SHIFT_CURSOR 0
#define HD44780_EM_SHIFT_DISPLAY 1
#define HD44780_EM_DECREMENT 0
#define HD44780_EM_INCREMENT 2
#define HD44780_DISPLAY_ONOFF 0x08
#define HD44780_DISPLAY_OFF 0
#define HD44780_DISPLAY_ON 4
#define HD44780_CURSOR_OFF 0
#define HD44780_CURSOR_ON 2
#define HD44780_CURSOR_NOBLINK 0
#define HD44780_CURSOR_BLINK 1
#define HD44780_DISPLAY_CURSOR_SHIFT 0x10
#define HD44780_SHIFT_CURSOR 0
#define HD44780_SHIFT_DISPLAY 8
#define HD44780_SHIFT_LEFT 0
#define HD44780_SHIFT_RIGHT 4
#define HD44780_FUNCTION_SET 0x20
#define HD44780_FONT5x7 0
#define HD44780_FONT5x10 4
#define HD44780_ONE_LINE 0
#define HD44780_TWO_LINE 8
#define HD44780_4_BIT 0
#define HD44780_8_BIT 16
#define HD44780_CGRAM_SET 0x40
#define HD44780_DDRAM_SET 0x80

#define PORT(x) XPORT(x)
#define XPORT(x) (PORT##x)
#define PIN(x) XPIN(x)
#define XPIN(x) (PIN##x)
#define DDR(x) XDDR(x)
#define XDDR(x) (DDR##x)

#define LCD_DATA_PORT D
#define LCD_RS_PORT D
#define LCD_RW_PORT D
#define LCD_E_PORT D
#define LCD_D4_PIN 4
#define LCD_D5_PIN 5
#define LCD_D6_PIN 6
#define LCD_D7_PIN 7
#define LCD_RS_PIN 1
#define LCD_RW_PIN 2
#define LCD_E_PIN 3

void LCD_init(void);
void LCD_clear(void);
void LCD_goto(uint8_t x, uint8_t y);
void LCD_write_text(char * text);

int main(void) {
 DDRC |= (1<<PC0);
 PORTC |= (1<<PC0);
 
 LCD_init();
 LCD_clear();
 LCD_goto(1,0);
 LCD_write_text("TEST!TEST!TEST!");
 
 while(1);
  
 return 0;
}

uint8_t LCD_in_bits(void)
{
    uint8_t tmp = 0;
    if(((PIN(LCD_DATA_PORT) >> LCD_D4_PIN) & 0x01) != 0)
        tmp |= (1 << 0);
    if(((PIN(LCD_DATA_PORT) >> LCD_D5_PIN) & 0x01) != 0)
        tmp |= (1 << 1);
    if(((PIN(LCD_DATA_PORT) >> LCD_D6_PIN) & 0x01) != 0)
        tmp |= (1 << 2);
    if(((PIN(LCD_DATA_PORT) >> LCD_D7_PIN) & 0x01) != 0)
        tmp |= (1 << 3);
    return tmp;
}

uint8_t LCD_read(void)
{
    uint8_t tmp = 0;
    DDR(LCD_DATA_PORT) &=
        ~((1<<LCD_D4_PIN)|(1<<LCD_D5_PIN)|(1<<LCD_D6_PIN)|(1<<LCD_D7_PIN));
    PORT(LCD_RW_PORT) |= (1<<LCD_RW_PIN);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    tmp |= (LCD_in_bits() << 4);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    tmp |= LCD_in_bits();
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    return tmp;
}

uint8_t LCD_ReadStatus(void)
{
    PORT(LCD_RS_PORT) &= ~(1<<LCD_RS_PIN);
    return LCD_read();
}

void LCD_out_bits(uint8_t bits_to_write)
{
    if(bits_to_write & 0x01)
        PORT(LCD_DATA_PORT) |= (1<<LCD_D4_PIN);
    else
        PORT(LCD_DATA_PORT) &= ~(1<<LCD_D4_PIN);
    if(bits_to_write & 0x02)
        PORT(LCD_DATA_PORT) |= (1<<LCD_D5_PIN);
    else
        PORT(LCD_DATA_PORT) &= ~(1<<LCD_D5_PIN);
    if(bits_to_write & 0x04)
        PORT(LCD_DATA_PORT) |= (1<<LCD_D6_PIN);
    else
        PORT(LCD_DATA_PORT) &= ~(1<<LCD_D6_PIN);
    if(bits_to_write & 0x08)
        PORT(LCD_DATA_PORT) |= (1<<LCD_D7_PIN);
    else
        PORT(LCD_DATA_PORT) &= ~(1<<LCD_D7_PIN);
}

void LCD_write(uint8_t data_to_write)
{
    DDR(LCD_DATA_PORT) |=
        ((1<<LCD_D4_PIN)|(1<<LCD_D5_PIN)|(1<<LCD_D6_PIN)|(1<<LCD_D7_PIN));
    PORT(LCD_RW_PORT) &= ~(1<<LCD_RW_PIN);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    LCD_out_bits(data_to_write >> 4);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    LCD_out_bits(data_to_write);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
    while(LCD_ReadStatus() & 0x80);
}

void LCD_just_write(uint8_t data_to_write)
{
    DDR(LCD_DATA_PORT) |=
        ((1<<LCD_D4_PIN)|(1<<LCD_D5_PIN)|(1<<LCD_D6_PIN)|(
             1<<LCD_D7_PIN));
    PORT(LCD_RW_PORT) &= ~(1<<LCD_RW_PIN);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    LCD_out_bits(data_to_write >> 4);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    LCD_out_bits(data_to_write);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
}

void LCD_just_write_command(uint8_t commandToWrite)
{
    PORT(LCD_RS_PORT) &= ~(1<<LCD_RS_PIN);
    LCD_just_write(commandToWrite);
}
void LCD_just_write_data(uint8_t data_to_write)
{
    PORT(LCD_RS_PORT) |= (1<<LCD_RS_PIN);
    LCD_just_write(data_to_write);
}
uint8_t LCD_NotBusy(void)
{
    if(LCD_ReadStatus() != 0x80)
        return 1;
    else
        return 0;
}

void LCD_write_command(uint8_t commandToWrite)
{
    PORT(LCD_RS_PORT) &= ~(1<<LCD_RS_PIN);
    LCD_write(commandToWrite);
}

void LCD_write_data(uint8_t data_to_write)
{
    PORT(LCD_RS_PORT) |= (1<<LCD_RS_PIN);
    LCD_write(data_to_write);
}

uint8_t LCD_read_data(void)
{
    PORT(LCD_RS_PORT) |= (1<<LCD_RS_PIN);
    return LCD_read();
}

void LCD_write_text(char * text)
{
    while(*text != '\0' && *text != 0)
        LCD_write_data(*text++);
}

void LCD_goto(uint8_t x, uint8_t y)
{
    LCD_write_command(HD44780_DDRAM_SET | (x + (0x40 * y)));
}

void LCD_clear(void)
{
    LCD_write_command(HD44780_CLEAR);
    _delay_ms(2);
}

void LCD_home(void)
{
    LCD_write_command(HD44780_HOME);
    _delay_ms(2);
}

void LCD_init(void)
{
    uint8_t i;
    DDR(LCD_DATA_PORT) |=
        ((1<<LCD_D4_PIN)|(1<<LCD_D5_PIN)|(1<<LCD_D6_PIN)|(1<<LCD_D7_PIN));
    DDR(LCD_RS_PORT) |= (1<<LCD_RS_PIN);
    DDR(LCD_RW_PORT) |= (1<<LCD_RW_PIN);
    DDR(LCD_E_PORT) |= (1<<LCD_E_PIN);
    _delay_ms(15);
    PORT(LCD_RS_PORT) &= ~(1<<LCD_RS_PIN);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    PORT(LCD_RW_PORT) &= ~(1<<LCD_RW_PIN);
    for(i = 0; i < 3; i++)
    {
        PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
        LCD_out_bits(0x03);
        PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
        _delay_ms(5);
    }

    PORT(LCD_E_PORT) |= (1<<LCD_E_PIN);
    LCD_out_bits(0x02);
    PORT(LCD_E_PORT) &= ~(1<<LCD_E_PIN);
    _delay_ms(1);
    LCD_write_command(HD44780_FUNCTION_SET | HD44780_FONT5x7 | HD44780_TWO_LINE |
                      HD44780_4_BIT);
    LCD_write_command(HD44780_DISPLAY_ONOFF | HD44780_DISPLAY_OFF);
    LCD_write_command(HD44780_CLEAR);
    LCD_write_command(HD44780_ENTRY_MODE | HD44780_EM_SHIFT_CURSOR |
                      HD44780_EM_INCREMENT);
    LCD_write_command(HD44780_DISPLAY_ONOFF | HD44780_DISPLAY_ON | HD44780_CURSOR_OFF |
                      HD44780_CURSOR_NOBLINK);
}