// flex_lcd.c

#define LCD_DB4   PIN_B4
#define LCD_DB5   PIN_B5
#define LCD_DB6   PIN_B6
#define LCD_DB7   PIN_B7

#define LCD_RS    PIN_C0
#define LCD_RW    PIN_C1
#define LCD_E     PIN_C2

// If you only want a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line.

#define USE_LCD_RW 1

//========================================

#define lcd_type 2 // 0=5x7, 1=5x10, 2=2 lines
#define lcd_line_two 0x40 // LCD RAM address for the 2nd line

int8 const LCD_INIT_STRING[4] =
{
  0x20 | (lcd_type << 2), // Func set: 4-bit, 2 lines, 5x8 dots
  0xc, // Display on
  1, // Clear display
  6 // Increment cursor
};


//-------------------------------------

void lcd_send_nibble(int8 nibble)
{
  // Note: !! converts an integer expression
  // to a boolean (1 or 0).
  output_bit(LCD_DB4, !!(nibble & 1));
  output_bit(LCD_DB5, !!(nibble & 2));
  output_bit(LCD_DB6, !!(nibble & 4));
  output_bit(LCD_DB7, !!(nibble & 8));

  delay_cycles(1);
  output_high(LCD_E);
  delay_cycles(2);// 2us
  output_low(LCD_E);
}

//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine. For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.

#ifdef USE_LCD_RW
int8 lcd_read_nibble(void)
{
  int8 retval;
  // Create bit variables so that we can easily set
  // individual bits in the retval variable.
  #bit retval_0 = retval.0
  #bit retval_1 = retval.1
  #bit retval_2 = retval.2
  #bit retval_3 = retval.3

  retval = 0;

  output_high(LCD_E);
  delay_cycles(1);

  retval_0 = input(LCD_DB4);
  retval_1 = input(LCD_DB5);
  retval_2 = input(LCD_DB6);
  retval_3 = input(LCD_DB7);

  output_low(LCD_E);

  return(retval);
}
#endif

//---------------------------------------
// Read a byte from the LCD and return it.

#ifdef USE_LCD_RW
int8 lcd_read_byte(void)
{
  int8 low;
  int8 high;

  output_high(LCD_RW);
  delay_cycles(1);

  high = lcd_read_nibble();

  low = lcd_read_nibble();

  return( (high<<4) | low);
}
#endif

//----------------------------------------
// Send a byte to the LCD.

void lcd_send_byte(int8 address, int8 n)
{
  output_low(LCD_RS);

#ifdef USE_LCD_RW
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif

  if(address)
  output_high(LCD_RS);
  else
  output_low(LCD_RS);

  delay_cycles(1);

#ifdef USE_LCD_RW
output_low(LCD_RW);
delay_cycles(1);
#endif

  output_low(LCD_E);

  lcd_send_nibble(n >> 4);
  lcd_send_nibble(n & 0xf);
}

//----------------------------

void lcd_init(void)
{
  int8 i;

  output_low(LCD_RS);

#ifdef USE_LCD_RW
output_low(LCD_RW);
#endif

  output_low(LCD_E);

  delay_ms(15);//15ms

  for(i=0 ;i < 3; i++)
  {
    lcd_send_nibble(0x03);
    delay_ms(5);//5ms
  }

  lcd_send_nibble(0x02);

  for(i=0; i < sizeof(LCD_INIT_STRING); i++)
  {
    lcd_send_byte(0, LCD_INIT_STRING[i]);

    // If the R/W signal is not used, then
    // the busy bit can't be polled. One of
    // the init commands takes longer than
    // the hard-coded delay of 60 us, so in
    // that case, lets just do a 5 ms delay
    // after all four of them.
#ifndef USE_LCD_RW
delay_ms(5);
#endif
}

}

//----------------------------

void lcd_gotoxy(int8 x, int8 y)
{
  int8 address;

  if(y != 1)
  address = lcd_line_two;
  else
  address=0;

  address += x-1;
  lcd_send_byte(0, 0x80 | address);
}

//-----------------------------

void lcd_putc(char c)
{
  switch(c)
  {
    case '\f':
      lcd_send_byte(0,1);
      delay_ms(2);//2ms
      break;

    case '\n':
      lcd_gotoxy(1,2);
      break;

    case '\b':
      lcd_send_byte(0,0x10);
      break;

    default:
      lcd_send_byte(1,c);
      break;
  }
}

//------------------------------
#ifdef USE_LCD_RW
char lcd_getc(int8 x, int8 y)
{
  char value;

  lcd_gotoxy(x,y);

  // Wait until busy flag is low.
  while(bit_test(lcd_read_byte(),7));

  output_high(LCD_RS);
  value = lcd_read_byte();
  output_low(lcd_RS);

  return(value);
}
#endif

void lcd_setcursor(short visible, short blink) {
  lcd_send_byte(0, 0xC|(visible<<1)|blink);
}