delay.h

#ifndef DELAY_H_
#define DELAY_H_

#include <delays.h>

#define delay1MicroSecond()	   {Delay10TCYx(1); Delay1TCY(); Delay1TCY();}
#define delay5MicroSecond()		Delay10TCYx(6) 
#define delay10MicroSecond()	Delay10TCYx(12)
#define delay50MicroSecond()	Delay10TCYx(60)
#define delay100MicroSecond()	Delay100TCYx(12)
#define delay200MicroSecond()	Delay100TCYx(24)
#define delay1MiliSecond()		Delay1KTCYx(12)
#define delay2MiliSecond()		Delay1KTCYx(24)
#define delay5MiliSecond()		Delay1KTCYx(60)
#define delay10MiliSecond()		Delay10KTCYx(12)
#define delay50MiliSecond()		Delay10KTCYx(60)
#define delay100MiliSecond()	Delay10KTCYx(120)	
#define delay200MiliSecond()	Delay10KTCYx(240)
#define delay1Second()		   {Delay10KTCYx(240); Delay10KTCYx(240); Delay10KTCYx(240);\
								Delay10KTCYx(240); Delay10KTCYx(240);}
#define delay2Second()		   {delay1Second(); delay1Second();}
#define delay5Second()		   {delay2Second(); delay2Second(); delay1Second();}
#define delay10Second()		   {delay5Second(); delay5Second();}

#endif

hd44780.c

#include "hd44780.h"
#include "delay.h"

void HD44780_Clock(void);
void HD44780_WriteByte(char reg, char dat);
void HD44780_WriteData(char dat);
void HD44780_WriteCommand(char dat);

void HD44780_Clock(void)
{
	HD44780_EN_PIN=1;			// starts data read
	delay50MicroSecond();
	HD44780_EN_PIN=0;			// starts data write
}
	
void HD44780_WriteByte(char reg, char dat)
{
	if(reg == HD44780_REGISTER_DATA)
	{
		HD44780_RS_PIN=1;
	}
	
	if(reg == HD44780_REGISTER_COMMAND)
	{
		HD44780_RS_PIN=0;
	}
	
	HD44780_EN_PIN=0;
	
	HD44780_DATA_PORT = dat;
	HD44780_Clock();
}

void HD44780_WriteData(char dat)
{
	HD44780_WriteByte(HD44780_REGISTER_DATA, dat);
	delay50MicroSecond();
}

void HD44780_WriteCommand(char dat)
{
	HD44780_WriteByte(HD44780_REGISTER_COMMAND, dat);
	delay2MiliSecond();
}

void HD44780_Init(void)
{
	//Using initialize by instruction
	//After power on Wait for LCD to Initialize
	delay100MiliSecond();
	HD44780_initPinIO();
	
	HD44780_EN_PIN	 = 0;
    HD44780_RS_PIN	 = 0;
	HD44780_DATA_PORT = 0x30;
	HD44780_Clock();
	delay5MiliSecond();
	
	HD44780_DATA_PORT = 0x30;
	HD44780_Clock();
	delay200MicroSecond();
	
    HD44780_DATA_PORT = 0x30;
	HD44780_Clock();
	delay200MicroSecond();
		
	// FUNCTION SET				| 0  0  1  1  N  F  *  * |
	// BIN_OR_BIT_MASK:			{ 0  0  1  1  1  0  0  0 }
	HD44780_WriteCommand(0x38);	// N = 1; 2 lines, F = 0; 5x8 dots
	delay5MiliSecond();
	// DISPLAY OFF
	HD44780_WriteCommand(0x0C);
	delay5MiliSecond();
	// DISPLAY CLEAR
	HD44780_WriteCommand(0x01);
	delay5MiliSecond();
	// ENTRY MODE SET			| 0  0  0  0  0  1  I/D  S |
	// BIN_OR_BIT_MASK:			{ 0  0  0  0  0  1   1   0 }
	HD44780_WriteCommand(0x06);	// I/D = 1; Increment by 1, S = 0; No shift
	delay5MiliSecond();
	// HOME POSITION
	HD44780_WriteCommand(0x80);
}

void HD44780_WriteString(const rom char *s)
{
	while(*s)
	{
		HD44780_WriteData(*s);
		s++;
	}
}
	
void HD44780_GoToPoint(char row, char col)
{
	char DDRAM_address;
	
	if(row<1) row=1;				// first position user-defined as (1,1)
	if(col<=1)col=0;				// but HD44780 defines as (0,0)
	else col=col-1;

	if(row==1) DDRAM_address = 0x80+col;		// 0x80 for set DDRAM address command
	if(row==2) DDRAM_address = 0x80+0x40+col;	// 0x40 for second line DDRAM address

	HD44780_WriteCommand(DDRAM_address);
}

hd44780.h

#ifndef HD44780_H
#define HD44780_H

#include <p18cxxx.h>
#include "delay.h"

#define HD44780_REGISTER_COMMAND	0x10
#define HD44780_REGISTER_DATA		0x01

#define HD44780_initPinIO()		   {TRISBbits.RB4=0; TRISBbits.RB5=0; TRISD=0x00;}
#define HD44780_EN_PIN				LATBbits.LATB5
#define HD44780_RS_PIN				LATBbits.LATB4
#define HD44780_DATA_PORT			LATD

void HD44780_Init(void); 
void HD44780_WriteString(const rom char *s);
void HD44780_GoToPoint(char row, char col);

#endif

main.c

        #pragma config PLLDIV   = 5         // (20 MHz crystal on PICDEM FS USB board)
        #pragma config CPUDIV   = OSC1_PLL2  
        #pragma config USBDIV   = 2         // Clock source from 96MHz PLL/2
        #pragma config FOSC     = HSPLL_HS
        #pragma config FCMEN    = OFF
        #pragma config IESO     = OFF
        #pragma config PWRT     = OFF
        #pragma config BOR      = ON
        #pragma config BORV     = 3
        #pragma config VREGEN   = ON      //USB Voltage Regulator
        #pragma config WDT      = OFF
        #pragma config WDTPS    = 32768
        #pragma config MCLRE    = ON
        #pragma config LPT1OSC  = OFF
        #pragma config PBADEN   = OFF
//      #pragma config CCP2MX   = ON
        #pragma config STVREN   = ON
        #pragma config LVP      = OFF
//      #pragma config ICPRT    = OFF       // Dedicated In-Circuit Debug/Programming
        #pragma config XINST    = OFF       // Extended Instruction Set
        #pragma config CP0      = OFF
        #pragma config CP1      = OFF
//      #pragma config CP2      = OFF
//      #pragma config CP3      = OFF
        #pragma config CPB      = OFF
//      #pragma config CPD      = OFF
        #pragma config WRT0     = OFF
        #pragma config WRT1     = OFF
//      #pragma config WRT2     = OFF
//      #pragma config WRT3     = OFF
        #pragma config WRTB     = OFF       // Boot Block Write Protection
        #pragma config WRTC     = OFF
//      #pragma config WRTD     = OFF
        #pragma config EBTR0    = OFF
        #pragma config EBTR1    = OFF
//      #pragma config EBTR2    = OFF
//      #pragma config EBTR3    = OFF
        #pragma config EBTRB    = OFF

#include <p18f4553.h>
#include "hd44780.h"
#include "delay.h"

#define mInitAllLEDs()     {TRISBbits.TRISB6=0; TRISBbits.TRISB7=0;}
#define mLED_1              LATBbits.LATB6
#define mLED_2              LATBbits.LATB7


void main()
{
	mInitAllLEDs();
	delay1Second();
	mLED_1 = 1;
	mLED_2 = 1;
	HD44780_Init();
	mLED_1 = 0;
	mLED_2 = 0;

	HD44780_GoToPoint(1,1);
	HD44780_WriteString("A");
	HD44780_GoToPoint(1,9);
	HD44780_WriteString("B");
	HD44780_GoToPoint(2,1);
	HD44780_WriteString("C");
	HD44780_GoToPoint(2,9);
	HD44780_WriteString("D");

	while(1)
	{
		delay1Second();
		mLED_1 = 1;
		mLED_2 = 0;
		delay1Second();
		mLED_1 = 0;
		mLED_2 = 1;
	}
}