/*
 * Lab5_Task3_LCD.c
 *
 * Created: 2024-05-06 18:15:10
 * Author : ralli
 */ 

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

#define DATA0 PD0
#define DATA1 PD1
#define DATA2 PD2
#define DATA3 PD3
#define DATA4 PD4
#define DATA5 PD5
#define DATA6 PD6
#define DATA7 PD7

#define RS	  PB0
#define E	    PB1

const uint8_t CURSOR_POSITIONS[2][16] = {
  {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F},
  {0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F}
};


int main(void)
{

	INIT_DATAPINS();
	INIT_LCD();
	
  LCD_DISPLAY_STRING("Voltage:", 8);
  LCD_SET_CURSOR_POSITION(0,15);
  LCD_DISPLAY_STRING("V", 1);

  LCD_SET_CURSOR_POSITION(1,0);
  LCD_DISPLAY_STRING("Light:", 6);
  LCD_SET_CURSOR_POSITION(1,15);
  LCD_DISPLAY_STRING("%", 1);

  while (1);
}

void INIT_LCD(void){
	PORTB &= (0 << RS);
	LCD_DISPLAY_ON_OFF_CONTROL();
  LCD_FUNCTION_SET();
  LCD_ENTRY_MODE_SET();
	PORTB |= (1 << RS);
}

void LCD_DISPLAY_STRING(char* str, uint8_t length){
  for(int i = 0; i < length; i++){
    char character = str[i];
    LCD_DISPLAY_CHAR(character);
  }
}

void LCD_DISPLAY_CHAR(unsigned int ascii_value){
  PORTD = ascii_value;
  	LCD_ENABLE();

}

/*TELLS LCD TO USE 8 DATA-PINS FOR INFORMATION. ENABLES DISPLAY TO USE 2 LINES OF TEXT.
  FUNCTION SET
  RS:           0
  RW:           0
  
  MODE:           4-bit DATA4 LOW
               -> 8-bit DATA4 HIGH
  
  LINENUMBER:     1-line DATA3 LOW
               -> 2-line DATA3 HIGH

  DOTS:        -> 5x8  DOTS LETTERS DATA2 LOW
                  5x11 DOTS LETTERS DATA2 HIGH
*/
void LCD_FUNCTION_SET(void){
  // 0011 1000 8-bit mode, 2 line, 5x8 format
	PORTD = 0;
  PORTD |= (0 << DATA7) | (0 << DATA6) | (1 << DATA5) | (1 << DATA4) | (1 << DATA3) | (0 << DATA2) | (0 << DATA1) | (0 << DATA0);
}

void INIT_DATAPINS(void){
	DDRD =  0b11111111;
	DDRB = (1 << E) | (1 << RS);
}

/* CLEARS ENTIRE DISPLAY, AND SENDS CURSOR TO STARTING POSITION
  CLEAR DISPLAY
  RS:           0
  RW:           0
*/
void LCD_CLEAR_DISPLAY(void){
	// 0000 0001  CLEAR DISPLAY
	PORTD = 0;
	PORTD |= (0 << DATA7) | (0 << DATA6) | (0 << DATA5) | (0 << DATA4) | (0 << DATA3) | (0 << DATA2) | (0 << DATA1) | (1 << DATA0);
	LCD_ENABLE();
}

/* SENDS CURSOR TO STARTING POSITION
  CLEAR DISPLAY
  RS:           0
  RW:           0
*/
void LCD_RETURN_HOME(void){
	// 0000 0010  RETURN HOME
	PORTD = 0;
	PORTD |= (0 << DATA7) | (0 << DATA6) | (0 << DATA5) | (0 << DATA4) | (0 << DATA3) | (0 << DATA2) | (1 << DATA1) | (0 << DATA0);
	LCD_ENABLE();
}

/* TELLS THE LCD TO READ DATAPINS, RW & RS PINS, AND DO OPERATION. THE ENABLE-PIN IS HIGH FOR A SHORT WHILE, THEN GOES LOW AGAIN. 
   AFTER SETTING UP THE DATAPINS, THE ENABLE NEEDS TO BE TOGGLED FOR THE CHARACTER TO DISPLAY.
  E:           1
*/
void LCD_ENABLE(void){
		_delay_us(1);
		PORTB ^= (1 << E);
		_delay_us(1);
		PORTB ^= (1 << E);
}

void LCD_SET_CURSOR_POSITION(int row, int column){
  LCD_SET_DDRAM_ADDRESS(CURSOR_POSITIONS[row][column]);
  //Serial.println(CURSOR_POSITIONS[row][column]);
}

void LCD_SET_DDRAM_ADDRESS(unsigned char address){
  PORTB &= (0 << RS);
	PORTD = 128;
	PORTD |= address;
  LCD_ENABLE();
  PORTB |= (1 << RS);

  
}

/*SETTINGS FOR DISPLAY ON/OFF, CURSOR ON/OFF, BLINKING CURSOR ON/OFF
  FUNCTION SET
  RS:           0
  RW:           0
  
  DISPLAY ON/OFF:     DISPLAY OFF DATA2 LOW 
                    ->DISPLAY ON  DATA2 HIGH
  
  CURSOR ON/OFF:       CURSOR OFF DATA1 LOW
                    -> CURSOR ON  DATA1 HIGH

  BLINKING ON/OFF:  -> BLINKING CURSOR OFF DATA0 LOW
                       BLINKING CURSOR ON  DATA0 HIGH
*/
void LCD_DISPLAY_ON_OFF_CONTROL(void){
	// 0000 1111  DISPLAY ON, CURSOR ON, BLINK ON
	PORTD = 0;
	PORTD |= (0 << DATA7) | (0 << DATA6) | (0 << DATA5) | (0 << DATA4) | (1 << DATA3) | (1 << DATA2) | (1 << DATA1) | (1 << DATA0);
	LCD_ENABLE();
}

/*SETTINGS FOR WHICH WAY THE CURSOR MOVES, CONTROLS TO SHIFT ENTIRE DISPLAY LEFT/RIGHT
  FUNCTION SET
  RS:           0
  RW:           0
  
  INCREMENT/DECREMENT:    CURSOR TO LEFT  DATA1 LOW 
                        ->CURSOR TO RIGHT DATA1 HIGH
  

  IF INCREMENT IS HIGH = SHIFT LEFT, INCREMENT IS LOW = SHIFT RIGHT
  SHIFT LEFT/RIGHT:       SHIFT DATA0 HIGH


  BLINKING ON/OFF:     -> BLINKING CURSOR OFF DATA0 LOW
                          BLINKING CURSOR ON  DATA0 HIGH
*/
void LCD_ENTRY_MODE_SET(void){
  // 0000 0000 Left->Right
  PORTD = 0;
	PORTD |= (0 << DATA7) | (0 << DATA6) | (0 << DATA5) | (0 << DATA4) | (0 << DATA3) | (1 << DATA2) | (1 << DATA1) | (0 << DATA0);
}