/* File: LCD.C */

/****************************************************************************
*
* STK16XSW.LCD
* ============
*
* Routines for controlling LCD with 2x16 characters on I2C bus
*                 
* TQ-Systems GmbH                                                         
* ---------------                                                         
* Customer: TQ-Components
* Project : STK16XSW
* Tools   : uVision 2.05
*
* Rev: Date:     Name:            Modification:
* ----+---------+----------------+------------------------------------------
* 100  16.01.01  A. Lichte        taken over from STK16X.506                
*****************************************************************************/

/****************************************************************************
*
*                             availability summary
*
* available for Starterkit: STK16X STK16XU
* conformed for Starterkit: STK16X 
* available for Modul     : TQM164   TQM165   TQM165U  TQM166  TQM167
*                           TQM167LC TQM167U  TQM167UL
* conformed for Modul     : TQM164   TQM165   TQM165U  TQM166  TQM167
*                           TQM167LC TQM167U  TQM167UL
*****************************************************************************/

/*==========================================================================*
* pragmas:
*===========================================================================*/

/*==========================================================================*
* include files (#INCLUDE):
*===========================================================================*/

/*--------------------------------------------------------------------------*
* standard include files: 
*---------------------------------------------------------------------------*/
#include <string.h>             /* string functions                        */
#include <reg167.h>             /* special function register               */

/*--------------------------------------------------------------------------*
* project specific include files:
*---------------------------------------------------------------------------*/
#include "lcd.h"
#include "timer.h"
#include "i2cio.h"

/*==========================================================================*
* module internal definitions (#DEFINE):
*===========================================================================*/

/*==========================================================================*
* module internal type declarations (TYPEDEF):
*===========================================================================*/

/*==========================================================================*
* module internal constants (CONST):
*===========================================================================*/

/*==========================================================================*
* extern available constants (CONST):
*===========================================================================*/

/*==========================================================================*
* modul internal variables:
*===========================================================================*/

/*--------------------------------------------------------------------------*
* LCD
*---------------------------------------------------------------------------*/
sbit LCD_EN      = P3^15;
sbit LCD_EN_DIR  = DP3^15;  

BYTE lcd_pos;                 /* actual cursor position                    */
BYTE lcd_ctrl = 0xFF;         /* shadow register for lcd data/ctrl signals */

/*==========================================================================*
* globale external available variables (EXTERN):
*===========================================================================*/

/*==========================================================================*
* modul internal functions:
*===========================================================================*/

/*--------------------------------------------------------------------------*
* void LCD_RSEL(BYTE mode)
*---------------------------------------------------------------------------*
* FT: set RSEL for LCD in shadow register
* EP: mode = 0: command register;  1: data register
* RW: -
* GP: shadow register lcd_ctrl 
*---------------------------------------------------------------------------*/
void LCD_RSEL(BYTE mode)
{
  lcd_ctrl = mode ? (lcd_ctrl | 0x10) : (lcd_ctrl & 0xEF);
  /* I/O pin will be actualized by the next LCD access */
}

/*--------------------------------------------------------------------------*
* void lcd_4bit_write(BYTE data)
*---------------------------------------------------------------------------*
* FT: write data to display with 4 bit data path
* EP: data = data to be written
* RW: -
* GP: shadow register lcd_ctrl 
*---------------------------------------------------------------------------*/
void lcd_4bit_write(BYTE data)
{ int i;

  lcd_ctrl = (lcd_ctrl & 0xD0) | (0x0F & data);

  i2c_write(LCD_I2C_ADR,1,lcd_ctrl); /* write data to LCD through i2c-bus */

  /* generate strobe on LCD_EN: */
  for (i=1; i<1000; i++);

  LCD_EN=0;

  for (i=1; i<1000; i++);

  LCD_EN=1;                 

  for (i=1; i<1000; i++);

  LCD_EN=0;
}

/*--------------------------------------------------------------------------*
* BYTE lcd_read(void)
*---------------------------------------------------------------------------*
* FT: write command to display with 4 bit data width
* EP: -
* RW: data from display
* GP: shadow register lcd_ctrl 
*---------------------------------------------------------------------------*/
BYTE lcd_read(void)
{ USHORT data1, data2;

  lcd_ctrl = (lcd_ctrl & 0xC0) | 0x2F;
  i2c_write(LCD_I2C_ADR, 1, lcd_ctrl);            /* set: 8 bit interface */

  LCD_EN = 1;
  i2c_read(LCD_I2C_ADR, 1, &data1);          /* read high nibble from LCD */
  LCD_EN = 0;

  timer_delay_20us(1);                                     /* delay 20 us */

  LCD_EN = 1;
  i2c_read(LCD_I2C_ADR, 1, &data2);           /* read low nibble from LCD */
  LCD_EN = 0;

  return(((data1 << 4) & 0xF0) | (data2 & 0x0F));
}

/*--------------------------------------------------------------------------*
* BYTE lcd_write(BYTE data)
*---------------------------------------------------------------------------*
* FT: write to display splitted in two 4 bit wide accesses
* EP: data = data / command to be written
* RW: data = command which has been written
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_write(BYTE data)
{
  lcd_4bit_write(data >> 4);                         /* write high nibble */
  lcd_4bit_write(data);                               /* write low nibble */

  return (data);
}

/*==========================================================================*
* extern available functions:
*===========================================================================*/

/*--------------------------------------------------------------------------*
* void lcd_init(void)
*---------------------------------------------------------------------------*
* FT: initialization LCD
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_init(void)
{
  /* port configuration: */
  LCD_EN = 0; 
  LCD_EN_DIR = 1;                             /* set LCD enable as output */
  LCD_EN = 1;

  LCD_RSEL(0);	       	                       /* select command register */

  /* commands to initialize send: */
     
  /* 1st LCD initializations step: */
  timer_delay_20us(750);             /* delay 15 ms                       */
  lcd_4bit_write(0x03);              /* configure LCD for 8 Bit interface */

  /* 2nd LCD initializations step: */
  timer_delay_20us(250);             /* delay 5 ms                        */
  lcd_4bit_write(0x03);              /* configure LCD for 8 Bit interface */

  /* 3rd LCD initializations step: */
  timer_delay_20us(250);             /* delay 5 ms                        */
  lcd_4bit_write(0x02);              /* configure LCD for 4 Bit interface */

  /* from this step on always two 8 bit cycles are required */

  /* 4th LCD initializations step: */
  timer_delay_20us(50);              /* delay 1 ms                        */
  lcd_write(0x2C);                   /* configure LCD for 2 lines         */
                                     /* and 5x10 dots                     */

  /* 5th LCD initializations step: */ 
  timer_delay_20us(50);              /* delay 1 ms                        */
  lcd_write(0x08);    	             /* display off                       */

  /* 6th LCD initializations step                                         */
  timer_delay_20us(50);              /* delay 1 ms                        */
  lcd_write(0x01);                   /* display clear                     */

  /* 7th LCD initializations step: */
  timer_delay_20us(50);              /* delay 1 ms                        */
  lcd_write(0x06);                   /* entry mode set; auto cursor left  */

  /* 8th LCD initializations step: */
  timer_delay_20us(50);              /* delay 1 ms                        */
  lcd_write(0x0C);                   /* display on                        */

  lcd_pos = 0;                       /* set cursor position to 0          */
}

/*--------------------------------------------------------------------------*
* void lcd_clr(void)
*---------------------------------------------------------------------------*
* FT: clear LCD
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_clr(void)
{
  LCD_RSEL(0);                                  /* select command register */
  lcd_write(0x01);                                        /* clear display */
  timer_delay_20us(100);                                     /* delay 2 ms */
  lcd_pos = 0;                                 /* set cursor position to 0 */
}

/*--------------------------------------------------------------------------*
* void lcd_setpos(BYTE new_pos)
*---------------------------------------------------------------------------*
* FT: set cursor to any position on the display
* EP: new_pos: position on display
*              +----------------------------------------------------+
*              | 0: upper left corner         15: upper right corner|
*              |64: lower left corner         79: lower right corner|
*              +----------------------------------------------------+
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_setpos(BYTE new_pos)
{
  lcd_pos = new_pos;                          /* save new cursor position */
  LCD_RSEL(0);                                 /* select command register */
  lcd_write(lcd_pos | 0x80);                /* set cursor to new position */
}

/*--------------------------------------------------------------------------*
* void lcd_home(void)
*---------------------------------------------------------------------------*
* FT: set cursor on upper left corner on display
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_home(void)
{
  lcd_pos = 0;                                /* set cursor position to 0 */
  LCD_RSEL(0);                                 /* select command register */
  lcd_write(lcd_pos | 0x80);                     /* set cursor on display */
}

/*--------------------------------------------------------------------------*
* void lcd_newline(void)
*---------------------------------------------------------------------------*
* FT: change to next line on display
*     previous line = 1: change to line 2
*     previous line = 2: change to line 1
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_newline(void)
{
  lcd_pos = (lcd_pos ^ 0x40) & 0x40;    /* calculate new cursor position   */
                                        /* => new cursor position: 0 or 64 */
  LCD_RSEL(0);                                  /* select command register */
  lcd_write(lcd_pos | 0x80);                 /* set cursor to new position */
}

/*--------------------------------------------------------------------------*
* void lcd_left(void)
*---------------------------------------------------------------------------*
* FT: move cursor one step left
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_left(void)
{
  lcd_pos = (lcd_pos - 1) & 0x4F;        /* calculate new cursor position */
  LCD_RSEL(0);                                 /* select command register */
  lcd_write(lcd_pos | 0x80);                /* set cursor to new position */
}

/*--------------------------------------------------------------------------*
* void lcd_right(void)
*---------------------------------------------------------------------------*
* FT: move cursor one step right
* EP: -
* RW: -
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
void lcd_right(void)
{
  lcd_pos = (lcd_pos + 1);               /* calculate new cursor position */
  if (lcd_pos & 0x10) 
  {
    lcd_newline();                               /* new line if necessary */
  }
  LCD_RSEL(0);                                 /* select command register */
  lcd_write(lcd_pos | 0x80);                /* set cursor to new position */
}

/*--------------------------------------------------------------------------*
* BYTE lcd_charout(BYTE c)
*---------------------------------------------------------------------------*
* FT: write character c to display at actual cursor position
*     and move cursor one step right
* EP: c = character to be written
* RW: character which has been written
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_charout(BYTE c)
{
  switch (c)
  {
    case LF : lcd_newline(); break;
    case '