/*
SUMMARY OF IMPORTANT LCD1602 COMMANDS
GIVEN 2 LINE MODE - 0X38 .THE WORD DISPLAY BEGINS FROM THE CURSOR POSITION 
THE ROW 1 ADDRESS IN DDRAM IS FROM 0X80 TO 0X8F FOR 16 COLS
THE ROW 2 ADDRESS IN DDRAM IS FROM 0XC0 TO 0XCF FOR 16 COLS

FEED THE ABOVE DDRAM POS ADDRESS AND WORD DISPLAY WILL START
FROM THE ADDRESS

THE 1 LINE MODE - 0X30 ONLY ROW 1 DDRAM ADDRESS MATTERS

TO SIMPLY SHIFT THE DISPLAY RIGHT FROM BEGINNING ONE TIME - 0X1C 
TO SIMPLY SHIFT THE DISPLAY LEFT ONE TIME - 0X18

TO SIMPLY SHIFT THE CURSOR RIGHT FROM BEGINNING ONE TIME - 0X14 
TO SIMPLY SHIFT THE CURSOR LEFT ONE TIME - 0X10

DISPLAY CONFIGURE COMMANDS
0X01- CLEAR THE DISPLAY
0X0C - DISPLAY ON, CURSOR OFF, BLINK OFF
0X0E - DISPLAY AND CURSOR ON, BLINK OFF
0X0F- DISPLAY, CURSOR AND BLINK IS ON

TO SHIFT CURSOR AND/OR DISPLAY USING ENTRY MODE INCREMENT OR DECREMENT

0X06- ONLY CURSOR GOES RIGHT
0X07 - BOTH CURSOR AND DISPLAY GO RIGHT
0X04 - ONLY CURSOR MOVES LEFT 
*/


#define E 0
#define RS 1

volatile uint8_t *porta = (volatile uint8_t *)0x22;
volatile uint8_t *portb = (volatile uint8_t *)0x25;

void my_delay(long t)
{
  for(volatile long i = 0; i< t*1000; i++);
}

void pulse_enable(void)
{
  *portb |= (1 << E);
    my_delay(1);
  *portb &= ~(1 << E);
}

void command(uint8_t c)
{
    *portb &= ~(1 << RS); /*RS = 0 FOR COMMAND*/
    *porta = c;
    pulse_enable();
    my_delay(2);
}

void data(uint8_t d)
{
  *portb |= (1 << RS); /*RS = 1 FOR DATA*/
  *porta = d;
  pulse_enable();
  my_delay(2);
}

void lcd_init_1()
{
  command(0x30);  // Function set: 8-bit, 1-line
  command(0x0E);  // Display ON, cursor ON
  command(0x01);  // Clear display
  command(0x06);  // Entry mode set: increment
}

void lcd_init_2()
{
  command(0x38);  // Function set: 8-bit, 2-line
  command(0x0E);  // Display ON, cursor ON
  command(0x01);  // Clear display
  command(0x06);  // Entry mode set: increment
}


uint8_t w1[8] = "Welcome";
uint8_t w2[11] = "To ETALVIS";

uint8_t r1[16] = {0x8f,0x8e,0x8d,0x8c,0x8b,0x8a,0x89,0x88,0x87,0x86,0x85,0x84,0x83,0x82,0x81,0x80};
/*move left in row 2*/
uint8_t r2[16] = {0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,0xcf};


void setup() {
  volatile uint8_t *ddra = (volatile uint8_t *)0x21;
volatile  uint8_t *ddrb = (volatile uint8_t *)0x24;
*ddra = 0xff;
*ddrb = 0x03;

}

void p1(uint8_t *x) /*by default left justified*/
{
  int i = 0;
  int j = 7;
  lcd_init_1();
    while(x[i] != '\0')
    {
      data(x[i]);
      i++;
      my_delay(20);
    }
      while(1);
}

/*method 1 manually shift the cursor to right side by 8 positions
and here cursor addr starts at the default position of the screen
and then start sending the data*/
void left_justified_1(uint8_t *w)
{
  int j = 0;
  lcd_init_1();
  /*right justified hence we shift the cursor to the right*/
    for(int i = 0; i<8; i++)
        command(0x14);
    while( w[j] != '\0')
    {
      data(w[j]);
      j++;
      my_delay(20);
    }
      while(1);
}

/*method 2 the cursor position starts at the 8th cell of row 1
no need to shift it to the right*/
void left_justified_2(uint8_t *w)
{
  int j = 0;
  lcd_init_1();
  
  /*start the cursor to the right by 8 positions
  and then send the data to accomodate 7 letter word welcome*/
  command(0x88);

      while( w[j] != '\0')
    {
      data(w[j]);
      j++;
      my_delay(20);
    }
      while(1);
}

void p2(uint8_t *w)
{
  left_justified_2(w);
}

/*method 2 to increment addr of the cursor to middle 
by command of cursor addr to start data display from
the middle*/
void to_middle_2(uint8_t *w)
{
    /*command to start cursor at the 4th cell*/
    lcd_init_1();
    command(0x84);
    int i = 0;
      while( w[i] != '\0')
      {
          data(w[i]);
            i++;
            my_delay(20);
      }
        while(1);

}

void p3(uint8_t *w)
{
    to_middle_2(w);
}

/*displaying the data in row 2 general scheme is 
row 1 base address is 0x80 and row 2 base address is 0xc0
so if command(0xc0) then the cursors starts at col 0 of row 2
  but the LCD must be configured in 2 lines mode*/

void show_left_row2(uint8_t *w)
{
    lcd_init_2();
    command(0xc0);
    int i = 0;
      while( w[i] != '\0')
      {
          data(w[i]);
          i++;
          my_delay(20);
      }
        while(1);
}

void p4(uint8_t *w)
{
    show_left_row2(w);
}

void show_right_row2(uint8_t *w)
{
    lcd_init_2();
      command(0xc8);
    int i = 0;
      while(w[i] != '\0')
      {
        data(w[i]);
        i++;
          my_delay(20);
      }
        while(1);
}

void p5(uint8_t *w)
{
    show_right_row2(w);
}

void to_middle_row2(uint8_t *w)
{
    lcd_init_2();
      command(0xc4); /*start the cursor at col 4 of row 2*/
    int i = 0;
      while( w[i] != '\0')
      {
        data(w[i]);
        i++;
          my_delay(20);
      }
        while(1);
}

void p6(uint8_t *w)
{
  to_middle_row2(w);
}

void two_words(uint8_t *w1, uint8_t *w2) /*each string has extra \0 to stop overlap
in the display*/
{
  lcd_init_2();
  command(0x84); /*start word 1 at col 4 on row 1*/
  int i = 0;
    while(w1[i] != '\0')
    {
      data(w1[i]);
      i++;
    }
        my_delay(100);
    command(0xc4);/*start word 2 at col4 on the row 2*/
    int j = 0;
      while(w2[j] != '\0')
      {
        data(w2[j]);
        j++;
      }
        while(1);
}

void p7(uint8_t *w1, uint8_t *w2)
{
    two_words(w1,w2);
}

void display_word(uint8_t *w,uint8_t x)
{
    lcd_init_2();
    command(x);
    int j = 0;
      while( w[j] != '\0')
      {
        data(w[j]);
          j++;
      }
}

void go_left(uint8_t *w, uint8_t *right)
{
    for(int i = 0; i<16; i++)
    {
        display_word(w,right[i]);
          my_delay(100);
    }
}

void p8(uint8_t *w, uint8_t *dir)
{
    go_left(w,dir);
}

void go_right(uint8_t *w, uint8_t *right, int limit)
{
    for(int i = 0; i<limit; i++)
    {
        display_word(w,right[i]);
          my_delay(100);
    }
}

void p9(uint8_t *w, uint8_t *right, int limit)
{
    go_right(w,right,limit);
}

void two_words_middle(uint8_t *w1, uint8_t *w2, uint8_t *c1, uint8_t *c2, int limit1, int limit2)
{
     for(int i = 0; i<limit1; i++)
    {
        display_word(w1,c1[i]);
          my_delay(100);
    }
        my_delay(100);
    for(int i = 0; i<limit2; i++)
    {
        display_word(w2,c2[i]);
          my_delay(100);
    }      
}

void two_words_middle_1(uint8_t *w1, uint8_t *w2, uint8_t *c1, uint8_t *c2, int limit1, int limit2)
{
     for(int i = 0; i<limit1; i++)
    {
        display_word(w1,c1[i]);
          my_delay(100);
    }
        display_word(w1,0x84);
        my_delay(1000);
    for(int i = 0; i<limit2; i++)
    {
        display_word(w2,c2[i]);
          my_delay(100);
    }      

    display_word(w2,0xcd);

    my_delay(10);

  while(1) {
    display_word(w1,0x84);
      my_delay(100);
    display_word(w2,0xc4);
      my_delay(100);   
  }

}

void p10(uint8_t *w1, uint8_t *w2, uint8_t *c1, uint8_t *c2, int l1, int l2)
{
  two_words_middle_1(w1,w2,c1,c2,l1,l2);
}

void loop() {
 
 p10(w1,w2,r1,r2,12,3);

}