lcd.c

Yet Another MP3 Player source code. It can be usefull as reference source for any project.

/*
  Copyright (C) 2001 Jesper Hansen <[e-mail]>.

  Rewritten by:	Nikolai Vorontsov <[e-mail]>

  This file is part of the yampp system.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software Foundation, 
  Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/


#include <io.h>

#include "lcd.h"
#include "mem.h"
#include "delay.h"
#include "uart.h"

#ifdef ENABLE_LCD

static u08 lcd_x, lcd_y;

/*************************************************************/
/********************** LOCAL FUNCTIONS **********************/
/*************************************************************/

static u08 LCDSetAddress(u08 adr) 
{ 
	return *(u08 *)(0x8000 + adr);		
	// dummy return to avoid optimization problems
}


static void lcd_write(u08 data, u08 rs) 
{
	// setup RS and RW pins
   	LCDSetAddress(rs + LCD_IO_WRITE);

	cbi(MCUCR, SRE);				// disable ExtRAM
	outp(0xff, DDR(LCD_DATA_PORT));	// set port as output
	outp(data, LCD_DATA_PORT);		// write byte
	lcd_e_high();					// set LCD enable high
	lcd_e_low();					// set LCD enable low
	sbi(MCUCR, SRE);				// enable ExtRAM
}


static u08 lcd_read_func(void)
{
    register u08 data;
	// setup RS and RW pins
   	LCDSetAddress(LCD_IO_FUNCTION + LCD_IO_READ);

	cbi(MCUCR, SRE);				// disable ExtRAM
	outp(0x00, DDR(LCD_DATA_PORT));	// set port as input
	lcd_e_high();					// set LCD enable high
	data = inp(PIN(LCD_DATA_PORT));	// read byte
	lcd_e_low();					// set LCD enable low
	sbi(MCUCR, SRE);				// enable ExtRAM

    return data;
}


static void lcd_waitbusy(void)		// loops while lcd is busy 
{									// no watchdog in this function
	register u08 i = 0;				// should work fast enough 
	while (lcd_read_func() & (1 << LCD_BUSY) && i != 255) i++;
}


static void lcd_newline(void)		// goto start of next line
{
    lcd_x = 0;
    if (++lcd_y >= LCD_LINES)
        lcd_y = 0;
}


static void lcd_goto(void)			// goto position (lcd_x,lcd_y)
{
	lcd_command((1 << LCD_DDRAM) + LCD_LINE_LENGTH * lcd_y + lcd_x);
}


/*************************************************************/
/********************* PUBLIC FUNCTIONS **********************/
/*************************************************************/

void lcd_command(u08 cmd)			// send commando <cmd> to LCD 
{
	lcd_waitbusy();
	lcd_write(cmd, LCD_IO_FUNCTION);
}


void lcd_data(u08 data)				// send data <data> to LCD
{
	lcd_waitbusy();
	lcd_write(data, LCD_IO_DATA);
}


void lcd_gotoxy(u08 x, u08 y)		// goto position (x,y) 
{
	lcd_x = x;  lcd_y = y;
	lcd_goto();
}


void lcd_clrscr(void)				// clear lcd
{
	lcd_x = lcd_y = 0;
	lcd_command(1 << LCD_CLR);
	delay10(200);					// 2 ms delay
}


#ifdef ENABLE_LCD_HOME_COMMAND
void lcd_home(void)					// set cursor
{									//  to home position
	lcd_x = lcd_y = 0;
	lcd_command(1 << LCD_HOME);
	delay10(200);					// 2 ms delay
}
#endif


void lcd_putchar(u08 data)			// print character to
{									//  current cursor position
	lcd_waitbusy();
	if (data == '\n')
	{
		lcd_newline();
		lcd_goto();
	}
	else
	{
		if (++lcd_x >= LCD_LINE_LENGTH)
		{
			lcd_newline();
			lcd_goto();
		}
		lcd_write(data, LCD_IO_DATA);
	}
}


void lcd_puts(u08* str)			// print string on lcd 
{								//  (no auto linefeed)
	if (str)
		while (*str)
			lcd_putchar(*str++);
}


static u16 wait[] = { 1600, 500, 7, 7 };

         
#endif

// cursor:   0 = off, 2 = on, 3 = blinking
// fnc: see LCD_FUNCTION_xxx
void lcd_init(u08 cursor, u08 fnc)
{
#ifdef ENABLE_LCD
	register u08 i;
#endif

	// configure control line pins as output
	sbi(DDR(LCD_E_PORT),  LCD_E_PIN);

	// set enable line high
	sbi(LCD_E_PORT, LCD_E_PIN);

	// done via ld option!!!
	// enable external SRAM (memory mapped lcd) and wait states
//	outp((1 << SRE) | (1 << SRW), MCUCR);

#ifdef ENABLE_LCD

	fnc |= (1 << LCD_FUNCTION);

	for (i = 0; i < 4; i++)					// reset lcd
	{
		delay10(wait[i]);					// 16ms, 5ms, 70us, 70us
		lcd_write(fnc, LCD_IO_FUNCTION);	// reset function
	}

	lcd_command(1 << LCD_ON);
	lcd_clrscr();

	lcd_command(LCD_MODE_DEFAULT);
	lcd_command((1 << LCD_ON)|(1 << LCD_ON_DISPLAY) | cursor);
#endif
}