#include <HC11A1.h>

// LCD Screen routines for the motorola 6811 using a Hitachi HD44780
// Written by Lee Rosenberg     rosenl@rpi.edu
// Developed for use with Introl C 4.0
// October 21, 1998

void OpenXLCD(char);	// configures I/O pins for external LCD
void SetDDRamAddr(char);	// sets display data address
char BusyXLCD(void);	// returns busy status of the LCD
void WriteCmdXLCD(char);	// write a command to the lcd
void WriteDataXLCD(char);	// writes data byte to the LCD
void WriteBuffer(char *buffer);	// Writes a string to the screen


// Write Buffer 
// Write a string of bytes to the HD44780

void WriteBuffer(char *buffer)
{
	while(*buffer)		// while buffer not empty
	{
		while(BusyXLCD());	// check if screen busy
		WriteDataXLCD(*buffer);	// write character to screen
		buffer++;		// increment pointer
	}
	return;
}

// OpenXLCD
//  This configures the LCD screen.

void OpenXLCD(char lcdtype)
{	int i;
	_H11PORTC = 0;
	_H11DDRC = 0x00;
	_H11PORTA = 0x00;

// delay for 15ms.  This is customized for the HC11 and must be changed for other processors

	for(i=0; i<40,000; i++);
	
// set up interface to LCD
	_H11DDRC = 0xFF;
	_H11PORTC = 0x3F;	// Function set command (8 bit)
	
	_H11PORTA = 0x20;	// clock cmd in
	for(i=0; i<30;i++);	// delay for ~18 clock cycles
	_H11PORTA = 0x00;

// delay for at least 4.1 ms
	for(i=0;i<9000;i++);

// setup interface
	_H11PORTC=0x3F;		// Function set command(8 bit)
	_H11PORTA = 0x20;	// clock in cmd
	for(i=0;i<30;i++);
	_H11PORTA = 0x00;

// delay for at least 100us
	for(i=0;i<500;i++);
	
// set up interface
	_H11PORTC = 0x3F;	// function set command (8 bit)
	_H11PORTA = 20;
	for(i=0;i<30;i++);
	_H11PORTA = 0x00;

	WriteCmdXLCD(lcdtype);	// function set cmd 8 bit interface
	WriteCmdXLCD(0x0C);
	WriteCmdXLCD(0x01);

	return;
}


// WriteCmdXLCD
// Writes a command to the controller

void WriteCmdXLCD(char cmd)
{
	int i;
	while(BusyXLCD());
	_H11DDRC = 0xFF;
	_H11PORTC = cmd;	// write cmd to port
	_H11PORTA = 0x00;	// set control signals

	for(i=0; i<30; i++);
	_H11PORTA=0x20;
	for(i=0;i<30;i++);
	_H11PORTA=0x00;

	for(i=0;i<30;i++);
	_H11DDRC=0x00;

	return;
}


// SetDDRamAddr
// Set the address of the LCD controller

void SetDDRamAddr(char DDaddr)
{
	int i;
	while(BusyXLCD());
	_H11DDRC=0xFF;
	_H11PORTC=(DDaddr | 0x80);	// write cmd and addr to port
	_H11PORTA=0x00;
	for(i=0;i<30;i++);
	_H11PORTA=0x20;
	for(i=0;i<30;i++);
	_H11PORTA=0x00;
	for(i=0;i<30;i++);
	_H11DDRC =0x00;
	return;
}


// BusyXLCD
// This checks the busy status of the HD 44780

char BusyXLCD(void)
{
	int i;
	_H11DDRC=0x00;
	_H11PORTA=0x08;		// set control bits
	for(i=0;i<30;i++);
	_H11PORTA=0x28;
	for(i=0;i<30;i++);
	
	if(_H11PORTC & 0x80)
	{
		_H11PORTA = 0x00;
		return 1;
	}
	else
	{
		_H11PORTA = 0x00;
		return 0;
	}
}


// WriteDataXLCD
// Writes data to the controller

void WriteDataXLCD(char data)
{
	int i;
	while(BusyXLCD());
	_H11DDRC = 0xFF;
	_H11PORTC = data;
	_H11PORTA = 0x10;
	
	for(i=0;i<30;i++);
	_H11PORTA=0x30;
	for(i=0;i<30;i++);
	_H11PORTA=0x00;
	_H11DDRC= 0x00;
	return;
}