Jason,

Here is some working 'C' code for setting up an HD44780 based LCD.  
Compare to yours the general idea. Note I always send the character 
position as the first byte of a display array. This is just my way of 
doing things, but that is why RS is changed in the data send function.

const char initLCD[]={0x33,0x32,0x28,0x01,0x02,0x0D,0};//spot the fact 
you use 0x3C when 0x03 has to be sent twice to switch to 4 bit mode.

/Library file for LCD and VFD displays that are HD44780 compliant
//
//Copyright C D Barnard 12/01/2003
//V1.01
//12/3/2003 amended  init wait time from 40uS to 1mS to cover all 
LCD's
//12/11/2008 added decimal point to disp_num for incubator project

#define TOP
#include <pic.h>

#include "incubator_lcd.h"

#include <delays.h>  //compiler provided library

#ifndef LCDPORT
  #define LCDPORT PORTB
#endif

#ifndef ENPORT
	#define ENPORT PORTB
#endif

#ifndef RSPORT
	#define RSPORT PORTB
#endif


//****************************************************************
// #define TOP = top nibble of port, not defined bottom nibble

void disp_init(unsigned char *tmpPtr)
{
   


   unsigned char currentCH;
     
   rs=0;
   Wait(20);			//Delay 20mS to enable LCD to initialise
  #ifdef TOP
  while(*tmpPtr)
 	{
    	currentCH=*tmpPtr;
    	LCDPORT&=0x0F;
    	LCDPORT|=(currentCH&0xF0);

    	sendit(rs);

//swap nibble

    	currentCH<<=4;
    	LCDPORT&=0x0F;
    	LCDPORT|=currentCH;

    	sendit(rs);
    	
    	Wait(1);

  	tmpPtr++;// increment pointer to next character in array
 	} 
  #else
  while(*tmpPtr)
	{
    	currentCH=*tmpPtr;
    	LCDPORT&=0xF0;
    	LCDPORT|=(currentCH&0x0F);

    	sendit(rs);
    	currentCH>>=4;
    	LCDPORT|=currentCH;

    	sendit(rs);
   
    	Wait(1);

  	 tmpPtr++;
 	} 
 #endif
}
//#endif

//#ifdef _display
void display(unsigned char *tmpPtr)
{
	
  unsigned char currentCH;
  
  rs=0;					//RS in Command mode for position byte
  
  #ifdef TOP
  while(*tmpPtr)		//LCD Data on bits D4-D7 of PORT
    {
    	currentCH=*tmpPtr;
    	LCDPORT&=0x0F;				
    	LCDPORT|=(currentCH&0xF0);	//Mask off upper nibble
    	sendit(rs);
    	currentCH<<=4;				//Now select lower nibble
    	LCDPORT&=0x0F;
    	LCDPORT|=currentCH;
    	sendit(rs);
    	t40();
  	rs=1;						//make sure RS is in data mode
    	tmpPtr++;					//get next character
        //#asmline clrwdt
    }
  #else				
  while(*tmpPtr)	//LCD Data on bits D0->D3 of PORT
    {
    	currentCH=*tmpPtr;
    	LCDPORT&=0xF0;
    	LCDPORT|=(currentCH&0x0F);
    	sendit(rs);
    	currentCH>>=4;
    	LCDPORT|=currentCH;
    	sendit(rs);
    	t40();
  	tmpPtr++;
 	} 
 #endif
 }

Colin
--
cdb, colin@btech-online.co.uk on 3/05/2010
 
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