//-----------------------------------------------------------------------------
// LCD.c
//-----------------------------------------------------------------------------
// Author: Baylor Electromechanical Systems
//
// Operates on an internal 2 MHz oscillator.
// 
// Target: Cygnal Educational Development Board / C8051F001
// Tool chain: KEIL C51 6.03 / KEIL EVAL C51
//
// Utilizes the C8051F001 as a serial LCD driver at 9600 bps. See accompanying
// documentation for more details. Code has been left commented to run on 
// external 18.432 MHz clock as well.
// 

//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f000.h>              // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------

//#define SYSCLK 18432000            // approximate SYSCLK frequency in Hz
#define SYSCLK 2000000             	// approximate SYSCLK frequency in Hz
#define BAUDRATE 9600				// baud rate for UART

sbit 	RS	= P0^5;
sbit	RW	= P0^6;
sbit	E	= P0^7;

static int DSP_CLR = 0x01;
static int FN_SET = 0x38;
static int LCD_OFF = 0x0B;
static int LCD_ON = 0x0F;
static int ENT_MD = 0x06;


//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void SYSCLK_Init (void);
void PORT_Init (void);
void LCD_DAT (unsigned char dat);
void LCD_CMD (unsigned char cmd);
void wait (int ms);
void LCD_Init (void);
void UART0_Init(void);
void banner (void);

//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------
bit row = 0;				// row indicator

//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------
void main (void) 
{

	unsigned char c;			// temp character
   	WDTCN = 0xde;				// disable watchdog timer
   	WDTCN = 0xad;
	SYSCLK_Init ();
	wait (1000);				// wait 1 sec for LCD to cycle on
	PORT_Init ();
	LCD_Init ();				// intialize LCD
	UART0_Init();
	wait (10);
	banner ();					// display boot up banner

	while (1)
	{
		c=_getkey();			// read in char
		switch (c)				
		  {
			case 0xfe : LCD_CMD (_getkey()); break;		// instruction
			case '\n' : break; 							// return and newline
			case '\r' :	 {	if (row) LCD_CMD (0x80);	// go to 1st line
							else LCD_CMD (0xc0);	}	// go to 2nd line
					 	break; 
			case '\0' :	LCD_DAT (0);	break;			// null byte		 
			default   : LCD_DAT (c);					// display character
	  	  }												// end switch
	}							// end while
}

//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------


//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use an 3.6864 MHz crystal
// as its clock source.
//
void SYSCLK_Init (void)
{
// 	int i;                          // delay counter
//	OSCXCN = 0x66;					// EXTERNAL Oscillator Control Register	
	
// 	for (i=0; i < 255; i++) ;       // XTLVLD blanking interval (>1ms)

//	while ( (OSCXCN & 0x80) == 0 );	// wait for xtal osc to start up

// 	OSCICN = 0x88;                  // select external oscillator as SYSCLK
                                    // source and enable missing clock
                                    // detector
		OSCICN = 0x94;				// Internal Oscillator enabled
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
void PORT_Init (void)
{
	XBR0    = 0x04;				// Enable UART
	XBR1    = 0x00;				
	XBR2    = 0x40;				// Enable crossbar and weak pull-ups
	PRT0CF |= 0xE0; 			// Output configuration for P0^5 - P0^7 
	PRT1CF  = 0xFF; 			// Output configuration for P1 
	P0      = 0x00;
	P1      = 0x00;

}

//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <baudrate> and 8-N-1.
//
void UART0_Init (void)
{
   SCON   = 0x50;                     	// SCON0: mode 1, 8-bit UART, enable RX
   SCON &= 0xFC; 						// clear interrupt pending flags
   TMOD    = 0x20;                  	// TMOD: timer 1, mode 2, 8-bit reload
   TCON = 0x40;							// Timer Control Register
   TH1    = -(SYSCLK/BAUDRATE/16);    	// set Timer1 reload value for baudrate
   TR1    = 1;                         	// start Timer1
   CKCON |= 0x10;                     	// Timer1 uses SYSCLK as time base
   PCON  |= 0x80;                      	// SMOD00 = 1
   TI    = 1;                         	// Indicate TX0 ready
}

//-----------------------------------------------------------------------------
// LCD_Init
//-----------------------------------------------------------------------------
void LCD_Init (void)
{
	E = 1;				wait (50);
	LCD_CMD (0x30);		wait (50);
	LCD_CMD (0x30);		wait (50);
	LCD_CMD (0x30);		wait (50);
	LCD_CMD (FN_SET);	wait (2);
	LCD_CMD (LCD_OFF);	wait (2);
	LCD_CMD (DSP_CLR);	wait (2);
	LCD_CMD (ENT_MD);	wait (2);
	LCD_CMD (LCD_ON);	wait (2);

}

//-----------------------------------------------------------------------------
// Local Functions
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// LCD_DAT
//-----------------------------------------------------------------------------
void LCD_DAT (unsigned char dat)
{

	P1 = 0x00;
	RS = 1;
	E = 1; P1 = dat;
	E = 0;
	E = 1; P1 = 0x00;

}

//-----------------------------------------------------------------------------
// LCD_CMD
//-----------------------------------------------------------------------------
void LCD_CMD (unsigned char cmd)
{
	if ((cmd == 0x01) || (cmd == 0x02))	// clear and home indicate row 0
		row = 0;
	else
		if ((cmd >= 0x80) && (cmd <= 0x8f))	
		  	row = 0;					// first row addresses indicate row 0
		else 
			if ((cmd >= 0xc0) && (cmd <= 0xcf))
				row = 1;   				// second row addresses indicate row 1

	P1 = 0x00;
	RS = 0;
	E = 1; P1 = cmd;
	E = 0;
	E = 1; P1 = 0x00;

}

//-----------------------------------------------------------------------------
// Wait
//-----------------------------------------------------------------------------
//
// This is an approximate X ms delay routine.
//
void wait (int ms)
{
	int i;
	int j;
	for (j = 1; j <= 50; j++) for (i = 1; i <= ms; i++);		

}



//-----------------------------------------------------------------------------
// Banner
//-----------------------------------------------------------------------------
//
// This routine displays a scrolling banner on the LCD. This function is 
// called at boot up.
//
void banner (void)
{
	LCD_CMD (DSP_CLR);				// clear LCD display
	wait (10);	
	LCD_CMD (0x85);	wait (1);   LCD_DAT ('C');  wait (150);
	LCD_DAT ('Y');	wait (150);	LCD_CMD (0x85);	wait (1);
	LCD_DAT (' ');	wait (1);	LCD_CMD (0x87);	wait (1);
	LCD_DAT ('G');	wait (150);	LCD_CMD (0x86);	wait (1);
	LCD_DAT (' ');	wait (1);	LCD_CMD (0x88);	wait (1);
	LCD_DAT ('N');	wait (150);	LCD_CMD (0x87);	wait (1);
	LCD_DAT (' ');	wait (1);	LCD_CMD (0x89);	wait (1);
	LCD_DAT ('A');	wait (150);	LCD_CMD (0x88);	wait (1);
	LCD_DAT (' ');	wait (1);	LCD_CMD (0x8a);	wait (1);
	LCD_DAT ('L');	wait (150);	LCD_CMD (0x89);	wait (1);
	LCD_DAT (' ');	wait (1);	LCD_CMD (0x8b);	wait (1);
	wait (150);	LCD_CMD (0x8a);	wait (1);	LCD_DAT (' ');
	wait (200);	LCD_CMD (0x85);	wait (1);	LCD_DAT ('C');	
	wait (1);	LCD_DAT ('Y');	wait (1);	LCD_DAT ('G');	
	wait (1);	LCD_DAT ('N');	wait (1);	LCD_DAT ('A');	
	wait (1);	LCD_DAT ('L');
	wait (3000); 					// wait 3 seconds at end
	LCD_CMD (DSP_CLR);				// clear LCD display
	wait (10);					
}