/***********************************************************************************
Filename: lcd.c
DESCRIPTION   LCD Module utility functions.
		Written for KS0066u compatible LCD Module.
		(8 characters by 2 lines)

Copyright   : 2006 Renesas Technology Europe Ltd.
Copyright   : 2006 Renesas Technology Corporation.
All Rights Reserved

***********************************************************************************/

/***********************************************************************************
Revision History
DD.MM.YYYY OSO-UID Description
26.07.2006 RTE-MBA First Release
***********************************************************************************/

/**********************************************************************************
System Includes
***********************************************************************************/
#include <machine.h>

/**********************************************************************************
User Includes
***********************************************************************************/
/* iodefine.h provides a structure to access all of the device registers. */
#include "iodefine.h"
/* rsk1664def.h provides common defines for widely used items. */
#include "rskrx210def.h"
#include "lcd.h"

/*****************************************************************************
Name:			InitDisplay 
Parameters:		none				
Returns:		none
Description:	Intializes the LCD display. 
*****************************************************************************/
void InitialiseDisplay( void )
{
	/* Power Up Delay for LCD Module */
	EN_PIN = SET_BIT_HIGH;
	DisplayDelay(7000);
	EN_PIN = SET_BIT_LOW;
  
	/* Display initialises in 8 bit mode - so send one write (seen as 8 bit)
		to set to 4 bit mode. */

	/* Function Set */
	LCD_nibble_write(CTRL_WR,0x03);
	LCD_nibble_write(CTRL_WR,0x03);
	DisplayDelay(39);
 
	/* Configure display */
	LCD_nibble_write(CTRL_WR,0x03);
	LCD_nibble_write(CTRL_WR,0x02);
	LCD_nibble_write(CTRL_WR,(LCD_DISPLAY_ON | LCD_TWO_LINE ));
	LCD_nibble_write(CTRL_WR,(LCD_DISPLAY_ON | LCD_TWO_LINE ));
	DisplayDelay(39);

	/* Display ON/OFF control */
	LCD_write(CTRL_WR,LCD_CURSOR_OFF);
	DisplayDelay(39);

	/* Display Clear */
	LCD_write(CTRL_WR,LCD_CLEAR);
	DisplayDelay(1530);

	/* Entry Mode Set */
	LCD_write(CTRL_WR,0x06);
	LCD_write(CTRL_WR,LCD_HOME_L1);
}
/**********************************************************************************
End of function InitialiseDisplay
***********************************************************************************/   

/*****************************************************************************
Name:		DisplayString   
Parameters:	position  Line number of display
			string	Pointer to data to be written to display.
					Last character should be null.
Returns:	none

Description:	This function controls LCD writes to line 1 or 2 of the LCD.
				You need to use the defines LCD_LINE1 and LCD_LINE2 in order
				to specify the starting position.
				For example, to start at the 2nd position on line 1...
				DisplayString(LCD_LINE1 + 1, "Hello")
*****************************************************************************/
void DisplayString(unsigned char position, char * string)
{
	static unsigned char next_pos = 0xFF;

	/* Set line position if needed. We don't want to if we don't need 
		to because LCD control operations take longer than LCD data
		operations. */
	if( next_pos != position)
	{
		if(position < LCD_LINE2)
		{
			/* Display on Line 1 */
			LCD_write(CTRL_WR, (unsigned char)(LCD_HOME_L1 + position) );
		}
		else
		{
			/* Display on Line 2 */
			LCD_write(CTRL_WR, (unsigned char)(LCD_HOME_L2 + position - LCD_LINE2) );
		}
		/* set position index to known value */
		next_pos = position;	
	}

	do
	{
		LCD_write(DATA_WR,*string++);
		/* increment position index */
		next_pos++;	   
	}
	while(*string);
}
/**********************************************************************************
End of function DisplayString
***********************************************************************************/   

/*****************************************************************************
Name:		LCD_write
Parameters:	value - the value to write
			data_or_ctrl - To write value as DATA or CONTROL
							1 = DATA
							0 = CONTROL
Returns:	none

Description:	Writes data to display. Sends command to display.  
*****************************************************************************/
void LCD_write(unsigned char data_or_ctrl, unsigned char value)
{
	/* Write upper nibble first */
	LCD_nibble_write(data_or_ctrl, (value & 0xF0) >> 4);

	/* Write lower nibble second */
	LCD_nibble_write(data_or_ctrl, (value & 0x0F));
}
/**********************************************************************************
End of function LCD_write
***********************************************************************************/   

/*****************************************************************************
Name:		LCD_nibble_write
Parameters:	value - the value to write
			data_or_ctrl - To write value as DATA or CONTROL
							1 = DATA
							0 = CONTROL
Returns:	none

Description:	Writes data to display. Sends command to display.  
*****************************************************************************/
void LCD_nibble_write(unsigned char data_or_ctrl, unsigned char value)
{
	unsigned char ucStore;
	if (data_or_ctrl == DATA_WR)
	{
		RS_PIN = SET_BIT_HIGH;
	}
	else
	{
		RS_PIN = SET_BIT_LOW;
	}
	/* There must be 40ns between RS write and EN write */
	DisplayDelay(1);
	/* EN enable chip (HIGH) */
	EN_PIN = SET_BIT_HIGH;
	/* Tiny delay */		
	DisplayDelay(1);
	/* Clear port bits used */  
	/* Set upper lower 4 bits of nibble on port pins. */
	ucStore = DATA_PORT;
	ucStore &= ~DATA_PORT_MASK;
	/* OR in data */  
	ucStore |= ((value << DATA_PORT_SHIFT) & DATA_PORT_MASK );
	/* Write lower 4 bits of nibble */
	DATA_PORT = ucStore;

	/* write delay while En High */
	DisplayDelay(20);
	/* Latch data by dropping EN */		 
	EN_PIN = SET_BIT_LOW;
	/* Data hold delay */	   
	DisplayDelay(20);		 

	if(data_or_ctrl == CTRL_WR)
	{
		/* Extra delay needed for control writes */
		DisplayDelay(40);	   
	}	   
}
/**********************************************************************************
End of function LCD_nibble_write
***********************************************************************************/   

/*****************************************************************************
Name:		DisplayDelay 
Parameters:	units - Approximately in microseconds				   
Returns:	none 

Description:   Delay routine for LCD display.
*****************************************************************************/
void DisplayDelay(unsigned long int units)
{
	unsigned long counter = units * DELAY_TIMING;
	while(counter--)
	{
		nop();		// ~ 10ns
	}
}
/**********************************************************************************
End of function DisplayDelay
***********************************************************************************/