C18 Questions

  #pragma code low_vector=0x08  // was 8x18
  void low_interrupt (void)
  {
    _asm GOTO interrupt _endasm
  }
  #pragma code
  #pragma interruptlow interrupt

#include <p18cxxx.h>
#include <stdio.h>
#include <delays.h>
#include "LCD.h"

//#pragma config OSC = INTIO67  //Internal oscillator
//#pragma config FCMEN = OFF //these are the 4 I commented out
#pragma config IESO = OFF
#pragma config PWRT = ON
//#pragma config BOREN = OFF
#pragma config WDT = OFF
#pragma config MCLRE = OFF     //MCLR is disabled
//#pragma config PBADEN = OFF
#pragma config LVP = OFF

void delay1s() {
	Delay10KTCYx(200);
}

//User defined putc for user defined output stream
void _user_putc(unsigned char c) {
	send_data(c); //Send character to LCD
}

void main() {
	OSCCON = 0b01110010; //8 MHz
	TRISC = 0x00; //PORTC is all output
	stdout = _H_USER; //Set to user-defined output stream via _user_putc

	lcd_init(); //Initialize the LCD
	send_cmd(0x0C); //Turn off cursor

	set_cursor(1, 1); //Set cursor to row 1, column 1
	printf("Hello!"); //Print "Hello!" to the LCD

	set_cursor(2, 1); //Set cursor to row 2, column 1
	printf("HD44780");

	while(1) {
		delay250ms(); //Scroll the display 1 character right every 250 ms
		sc_r();
	}
}

/*
 * PIC 16F886 HD44780 LCD Driver
 * Author:    solarwind
 * Date:      2009-01-31
 * Email:     x.solarwind.x@gmail.com
 * Compiler:  Microchip C18 (v3.22)
 * 
 * Pin Configuration:
 * 		The LCD's data 4 - 7 pins should be connected to bits 4 - 7,
 * 		respectively, of any port you wish to use on your PIC.
 * 
 * 		The E, R/W and RS pins can be connected to any unused port at
 * 		any pin.
 * 
 * 		My configuration is as follows:
 * 		LCD        PIC
 * 		16 BK-
 * 		15 BK+
 * 		14 D7   -> RC7
 * 		13 D6   -> RC6
 * 		12 D5   -> RC5
 * 		11 D4   -> RC4
 * 		10 D3
 * 		9  D2
 * 		8  D1
 * 		7  D0
 * 		6  E    -> RC0
 * 		5  R/W  -> RC1
 * 		4  RS   -> RC2
 * 		3  VO
 * 		2  VDD
 * 		1  VSS
 * 
 * Note:
 * 		This driver is designed to work with almost any PIC 18. Be sure to
 * 		correctly initialize your PIC, correctly connect your LCD and
 * 		define your connections below.
 * 
 * Note:
 * 		DDRAM Addresses are as follows on 16 x 4 displays:
 * 
 * 		Line 1:  0x00 -> 0x0F
 * 		Line 2:  0x40 -> 0x4F
 * 		Line 3:  0x10 -> 0x1F
 * 		Line 4:  0x50 -> 0x5F
 * 
 */

#ifndef LCD_H_
#define LCD_H_

#include "main.h"

//Define your LCD's data PORT here:
#define LCD_PORT PORTC

//Define your LCD's control pins here:
#define LCD_E  PORTCbits.RC0 //Enable
#define LCD_RW PORTCbits.RC1 //Read/write
#define LCD_RS PORTCbits.RC2 //Register select

void strobe(void);                      //Strobes the enable pin of the LCD
void send_nibble(byte b);               //Send high nibble of byte b to LCD
void send_byte(byte b);                 //Send entire byte b to LCD via 4 bit interface
void send_cmd(byte b);                  //Send command to LCD
void send_data(byte b);                 //Send data to LCD
void set_cursor(byte row, byte col);    //Set cursor position at (row, col)
void cursor_on(void);                   //Turn on cursor
void cursor_off(void);                  //Turn off cursor
void cls(void);                         //Clear screen
void sc_r(void);                        //Scroll all lines one character right
void sc_l(void);                        //Scroll all lines one character left
void home(void);                        //Send cursor to top-left position
byte b2hc(byte data);                   //Convert lower nibble of byte data to an ascii character
void lcd_init(void);                    //Initialize LCD

#endif /*LCD_H_*/

#include "LCD.h"
#include "delay.h"

void strobe() {
	LCD_E = 1;
	Nop();
	LCD_E = 0;
	Nop();
}

void send_nibble(byte b) {
	LCD_PORT = (LCD_PORT & 0x0F) | (b & 0xF0);
	strobe();
}

void send_byte(byte b) {
	send_nibble(b); //Send high nibble
	send_nibble(b << 4); //Send low nibble
}

void send_cmd(byte b) {
	LCD_RS = 0; //Command mode
	send_byte(b);
	delay5ms();
}

void send_data(byte b) {
	LCD_RS = 1; //Data mode
	send_byte(b);
	delay100us();
}

void set_cursor(byte row, byte col) {
	byte command = 0x80;
	switch(row) {
	case 1:
		command += col - 1;
		break;
	case 2:
		command += 0x40 + col - 1;
		break;
	case 3:
		command += 0x10 + col - 1;
		break;
	case 4:
		command += 0x50 + col - 1;
		break;
	default:
		command += col - 1;
		break;
	}
	send_cmd(command);
}

void cursor_on() {
	send_cmd(0x0E);
}

void cursor_off() {
	send_cmd(0x0C);
}

void cls() {
	send_cmd(0x01);
}

void sc_r() {
	send_cmd(0x1E);
}

void sc_l() {
	send_cmd(0x18);
}

void home() {
	send_cmd(0x02);
}

byte b2hc(byte data) {	
	switch(data & 0x0F) {
	case 0:
		return '0';
	case 1:
		return '1';
	case 2:
		return '2';
	case 3:
		return '3';
	case 4:
		return '4';
	case 5:
		return '5';
	case 6:
		return '6';
	case 7:
		return '7';
	case 8:
		return '8';
	case 9:
		return '9';
	case 10:
		return 'A';
	case 11:
		return 'B';
	case 12:
		return 'C';
	case 13:
		return 'D';
	case 14:
		return 'E';
	case 15:
		return 'F';
	}
	return 0;
}


void lcd_init() {
	delay100us(); //Delay for LCD to start itself up
	
	LCD_E = 0;
	LCD_RW = 0;
	LCD_RS = 0;
	
	//Start initializing the LCD
	send_nibble(0x30);
	delay5ms();
	send_nibble(0x30);
	delay5ms();	
	send_nibble(0x30);
	delay100us();
	send_nibble(0x20); //4 bit interface
	delay100us();
	
	send_cmd(0b00101000); //Function set: 4 bit interface
	send_cmd(0b00001110); //Display on/off: display on, cursor on, blink off
	send_cmd(0b00000110); //Entry mode: increment, no shift
	send_cmd(0b00000010); //Cursor home
	send_cmd(0b00000001); //Clear DDRAM/LCD
	delay5ms();	
}

#ifndef DELAY_H_
#define DELAY_H_

#include <delays.h>

//Required for LCD
void delay5ms(void);
void delay100us(void);

//Useful for user
void delay1s(void);
void delay250ms(void);
void delay100ms(void);

#endif /*_DELAY_H_*/

#include "delay.h"

//Required for LCD
void delay5ms() {
	Delay10KTCYx(4);
}

void delay100us() {
	Delay100TCYx(8);
}


//Useful for user
void delay1s() {
	Delay10KTCYx(200);
	Delay10KTCYx(200);
	Delay10KTCYx(200);
	Delay10KTCYx(200);
}

void delay250ms() {
	Delay10KTCYx(200);
}

void delay100ms() {
	Delay10KTCYx(80);
}

void strobe(void);                      //Strobes the enable pin of the LCD
//63 (below)
void send_nibble(byte b);               //Send high nibble of byte b to LCD
void send_byte(byte b);                 //Send entire byte b to LCD via 4 bit interface
void send_cmd(byte b);                  //Send command to LCDio
void send_data(byte b);                 //Send data to LCD
void set_cursor(byte row, byte col);    //Set cursor position at (row, col)
void cursor_on(void);                   //Turn on cursor
void cursor_off(void);                  //Turn off cursor
void cls(void);                         //Clear screen
void sc_r(void);                        //Scroll all lines one character right
void sc_l(void);                        //Scroll all lines one character left
void home(void);                        //Send cursor to top-left position
byte b2hc(byte data);                   //Convert lower nibble of byte data to an ascii character
void lcd_init(void);                    //Initialize LCD