pyrorf/lcd.c

#include "lcd.h"
#include "i2c.h"
#include <util/delay.h>
#include <avr/pgmspace.h>

#define ENPIN 0
#define RWPIN 1
#define RSPIN 2
#define BLPIN 3

#define DATASHIFT 4


uint8_t _numlines;
uint8_t _cols;
uint8_t _En = (1<<ENPIN);
uint8_t _Rs = (1<<RSPIN);
uint8_t _Rw = (1<<RWPIN);
uint8_t _Bl = (1<<BLPIN);

uint8_t _BackliteOn = true;

uint8_t _displaymode;
uint8_t _displaycontrol;

void i2csend(uint8_t data){
	i2c_start();
	i2c_write(LCD_ADDRESS << 1);
	i2c_write(data);
	i2c_stop();
}

void pulseEnable (uint8_t data)
{
   i2csend (data | _En);   // En HIGH
   i2csend (data & ~_En);  // En LOW
}

void write4bits ( uint8_t value, uint8_t mode ) 
{
   uint8_t data = value << DATASHIFT;
   
   // Is it a command or data
   // -----------------------
   if ( mode == LCD_DATA )
   	   data |= _Rs;
   
   
   if (_BackliteOn)
       data |= _Bl;
   pulseEnable ( data );
}


void send(uint8_t value, uint8_t mode) 
{
   // No need to use the delay routines since the time taken to write takes
   // longer that what is needed both for toggling and enable pin an to execute
   // the command.
   
   if ( mode == FOUR_BITS )
   {
      write4bits( (value & 0x0F), COMMAND );
   }
   else 
   {
      write4bits( (value >> 4), mode );
      write4bits( (value & 0x0F), mode);
   }
}

void command(uint8_t value) 
{
   send(value, COMMAND);
}

void lcd_init(uint8_t cols, uint8_t lines)
{	
		i2c_init();
		_cols=cols;
		_numlines=lines;
		_delay_ms(100);
		
	  // this is according to the hitachi HD44780 datasheet
      // figure 24, pg 46
      
      // we start in 8bit mode, try to set 4 bit mode
      // Special case of "Function Set"
      send(0x03, FOUR_BITS);
      _delay_us(4500); // wait min 4.1ms
      
      // second try
      send ( 0x03, FOUR_BITS );
      _delay_us(150); // wait min 100us
      
      // third go!
      send( 0x03, FOUR_BITS );
      _delay_us(150); // wait min of 100us
      
      // finally, set to 4-bit interface
      send ( 0x02, FOUR_BITS );
      _delay_us(150); // wait min of 100us


	command(LCD_FUNCTIONSET | LCD_2LINE);
}

void lcd_clear()
{
   command(LCD_CLEARDISPLAY);             // clear display, set cursor position to zero
   _delay_us(HOME_CLEAR_EXEC);    // this command is time consuming
}

void lcd_home()
{
   command(LCD_RETURNHOME);             // set cursor position to zero
   _delay_us(HOME_CLEAR_EXEC);  // This command is time consuming
}

void lcd_setCursor(uint8_t col, uint8_t row)
{
   const uint8_t row_offsetsDef[]   = { 0x00, 0x40, 0x14, 0x54 }; // For regular LCDs
   const uint8_t row_offsetsLarge[] = { 0x00, 0x40, 0x10, 0x50 }; // For 16x4 LCDs
   
   if ( row >= _numlines ) 
   {
      row = _numlines-1;    // rows start at 0
   }
   
   // 16x4 LCDs have special memory map layout
   // ----------------------------------------
   if ( _cols == 16 && _numlines == 4 )
   {
      command(LCD_SETDDRAMADDR | (col + row_offsetsLarge[row]));
   }
   else 
   {
      command(LCD_SETDDRAMADDR | (col + row_offsetsDef[row]));
   }  
}

// Turn the display on/off

void lcd_noDisplay() 
{
   _displaycontrol &= ~LCD_DISPLAYON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}

void lcd_display() 
{
   _displaycontrol |= LCD_DISPLAYON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns the underline cursor on/off
void lcd_noCursor() 
{
   _displaycontrol &= ~LCD_CURSORON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void lcd_cursor() 
{
   _displaycontrol |= LCD_CURSORON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns on/off the blinking cursor
void lcd_noBlink() 
{
   _displaycontrol &= ~LCD_BLINKON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}

void lcd_blink() 
{
   _displaycontrol |= LCD_BLINKON;
   command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// These commands scroll the display without changing the RAM
void lcd_scrollDisplayLeft(void) 
{
   command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}

void lcd_scrollDisplayRight(void) 
{
   command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}


// This method moves the cursor one space to the right
void lcd_moveCursorRight(void)
{
   command(LCD_CURSORSHIFT | LCD_CURSORMOVE | LCD_MOVERIGHT);
}

// This method moves the cursor one space to the left
void lcd_moveCursorLeft(void)
{
   command(LCD_CURSORSHIFT | LCD_CURSORMOVE | LCD_MOVELEFT);
}


// This is for text that flows Left to Right
void lcd_leftToRight(void) 
{
   _displaymode |= LCD_ENTRYLEFT;
   command(LCD_ENTRYMODESET | _displaymode);
}

// This is for text that flows Right to Left
void lcd_rightToLeft(void) 
{
   _displaymode &= ~LCD_ENTRYLEFT;
   command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'right justify' text from the cursor
void lcd_autoscroll(void) 
{
   _displaymode |= LCD_ENTRYSHIFTINCREMENT;
   command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'left justify' text from the cursor
void lcd_noAutoscroll(void) 
{
   _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
   command(LCD_ENTRYMODESET | _displaymode);
}


void lcd_createChar(uint8_t location, const char *charmap)
{
   location &= 0x7;   // we only have 8 memory locations 0-7
   
   command(LCD_SETCGRAMADDR | (location << 3));
   _delay_us(30);
   
   for (uint8_t i = 0; i < 8; i++)
   {
      lcd_write(pgm_read_byte_near(charmap++));
      _delay_us(40);
   }
}

void lcd_write(uint8_t value)
{
   send(value, LCD_DATA);
}