/* File: LCD.C */

/****************************************************************************
*
* STK16XSW.LCD
* ============
*
* Routines for controlling LCD with 2x16 characters
*                 
* 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
*      04.05.01  A. Lichte        display  read back status
*****************************************************************************/

/****************************************************************************
*
*                            availability summary
*
* available for Starterkit: STK16XU
* conformed for Starterkit: STK16XU 
* available for Modul     : TQM167UL TQM167U  TQM167UE
*                           
* conformed for Modul     : TQM167UL TQM167U  TQM167UE
*****************************************************************************/

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

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

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

/*--------------------------------------------------------------------------*
* project specific include files:
*---------------------------------------------------------------------------*/
#include "lcd_u.h"
#include "timer.h"
#include "stkreg_u.h"

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

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

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

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

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

/*--------------------------------------------------------------------------*
* LCD
*---------------------------------------------------------------------------*/

BYTE lcd_pos;                 /* actual cursor position                    */
BYTE lcd_rsel_sreg;           /* 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_rsel_sreg
*---------------------------------------------------------------------------*/
void LCD_RSEL(BYTE mode)
{
  if (mode) stkreg_sethigh(LCD_RS, LCD_RS);
  else stkreg_sethigh(LCD_RS, 0);
  lcd_rsel_sreg = mode;
}

/*--------------------------------------------------------------------------*
* BYTE LCD_GET_RSEL(void)
*---------------------------------------------------------------------------*
* FT: set RSEL for LCD in shadow register
* EP: mode = 0: command register;  1: data register
* RW: -
* GP: shadow register lcd_rsel_sreg
*---------------------------------------------------------------------------*/
BYTE LCD_GET_RSEL(void)
{
  return lcd_rsel_sreg;
}



/*--------------------------------------------------------------------------*
* BYTE lcd_read(void)
*---------------------------------------------------------------------------*
* FT: read command from display
* EP: -
* RW: data from display
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_read(void)
{
  BYTE val;
  int i;
  stkreg_sethigh(LCD_EN|LCD_R_W, LCD_R_W);  // EN => LOW / R/W# =>HIGH
  for (i=1; i<10; i++);
  /* generate strobe on LCD_EN: */
  stkreg_sethigh(LCD_EN, LCD_EN);     // EN => HIGH
  for (i=1; i<10; i++);
  val=stkreg_readlow();               // Read Data
  stkreg_sethigh(LCD_EN, 0);          // EN => LOW
  return (val);
}


/*--------------------------------------------------------------------------*
* BYTE lcd_cmd_walid(void)
*---------------------------------------------------------------------------*
* FT: Wait until LCD is redy to accept a new command
* EP: -
* RW: 0: Ready for new command; 1: Timeout 
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_cmd_walid(void)
{
  UINT ui;
  BYTE mode;
  mode = LCD_GET_RSEL();
  LCD_RSEL(0);	       	                       /* select command register */
  ui=0;
  while (ui<0x01FF)
  {
    if (!(lcd_read()&0x80)) { LCD_RSEL(mode); return 0; }  // LCD Ready
    ui++;
  }
  LCD_RSEL(mode);
  return 1; // Timeout
}


/*--------------------------------------------------------------------------*
* BYTE lcd_write(BYTE data)
*---------------------------------------------------------------------------*
* FT: write to display 
* EP: data = data / command to be written
* RW: 0: Byte written successfully; 1: Timeout 
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_write(BYTE data)
{
  int i;
  if (lcd_cmd_walid()) return 1;      // Wait until LCD accept command; 
                                      // stopp when Timeout
  stkreg_writelow(data);              // Write Data to Latch; do not write 
                                      // to Display, if R/W# is high
  for (i=1; i<10; i++);
  stkreg_sethigh(LCD_EN|LCD_R_W, 0);  // EN => LOW / R/W# =>LOW
  for (i=1; i<10; i++);
  /* generate strobe on LCD_EN: */
  stkreg_sethigh(LCD_EN, LCD_EN);     // EN => HIGH
  for (i=1; i<10; i++);
  stkreg_sethigh(LCD_EN, 0);          // EN => LOW / Write Data to Display
  return (0);
}

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

/*--------------------------------------------------------------------------*
* BYTE lcd_init(void)
*---------------------------------------------------------------------------*
* FT: initialization LCD
* EP: -
* RW: 0: Initialisation successfully; >0 : Timeout on Initialisation Step (RW)
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE lcd_init(void)
{
  BYTE rval;
  rval = 1;
  // port configuration: 
  stkreg_sethigh(LCD_EN, LCD_EN);
  LCD_RSEL(0);	                    // select command register 

  // commands to initialize send: 
     
  // 1st LCD initializations step: 
  lcd_write(0x3C);                  // First Function Set: 8 Bit, 2 lines, 5x10 dots 
  if (lcd_write(0x3C)) return rval; // Retry Function Set: 8 Bit, 2 lines, 5x10 dots 
  rval ++;                          // Der retry ist notwendig, weil das LCD ein Teil 
                                    // vom Kommando 黚ersieht, ist es auf 4 Bit 
                                    // initialisiert. Der erste Versuch stellt
                                    // auf jedem Fall auf 8 Bit um.

  // 2nd LCD initializations step:  
  if (lcd_write(0x08)) return rval;  // display off                      
  rval ++;

  // 3rd LCD initializations step                                        
  if (lcd_write(0x01)) return rval; // display clear                     
  rval ++;

  // 4th LCD initializations step: 
  if (lcd_write(0x06)) return rval; // entry mode set; auto cursor left  
  rval ++;

  // 5th LCD initializations step: 
  if (lcd_write(0x0C)) return rval; // display on                        

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

/*--------------------------------------------------------------------------*
* BYTE lcd_clr(void)
*---------------------------------------------------------------------------*
* FT: clear LCD
* EP: -
* RW: Success; 1: Timeout 
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE lcd_clr(void)
{
  LCD_RSEL(0);                                  /* select command register */
  lcd_pos = 0;                                 /* set cursor position to 0 */
  return lcd_write(0x01);                                        /* clear display */
}

/*--------------------------------------------------------------------------*
* BYTE 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: Success; 1: Timeout
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE lcd_setpos(BYTE new_pos)
{
  lcd_pos = new_pos;                          /* save new cursor position */
  LCD_RSEL(0);                                 /* select command register */
  return lcd_write(lcd_pos | 0x80);         /* set cursor to new position */
}

/*--------------------------------------------------------------------------*
* BYTE lcd_home(void)
*---------------------------------------------------------------------------*
* FT: set cursor on upper left corner on display
* EP: -
* RW: Success; 1: Timeout
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE lcd_home(void)
{
  lcd_pos = 0;                                /* set cursor position to 0 */
  LCD_RSEL(0);                                 /* select command register */
  return lcd_write(lcd_pos | 0x80);              /* set cursor on display */
}

/*--------------------------------------------------------------------------*
* BYTE 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: Success; 1: Timeout
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE 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 */
  return lcd_write(lcd_pos | 0x80);          /* set cursor to new position */
}

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

/*--------------------------------------------------------------------------*
* BYTE lcd_right(void)
*---------------------------------------------------------------------------*
* FT: move cursor one step right
* EP: -
* RW: Success; 1: Timeout
* GP: lcd_pos = cursor position
*---------------------------------------------------------------------------*/
BYTE 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 */
  return 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: Success; 1: Timeout
* GP: -
*---------------------------------------------------------------------------*/
BYTE lcd_charout(BYTE c)
{
  BYTE errflag;
  errflag = 0;
  switch (c)
  {
    case LF : errflag |= lcd_newline(); break;
    case '