lib/lcd-pcf8574.c

/*
 * lcd-pcf8574.c:
 *	Text-based LCD driver library code
 *	This is designed to drive the HD44780U LCD display connected via
 *	a "LCM1602 IIC  A0 A1 A2" board with a PCF8574 I2C controller.
 *
 * Copyright (c) 2012-2013 Gordon Henderson.
 * Copyright (c) 2014 Michiel Broek.
 ***********************************************************************
 *
 *    mbsePi is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    mbsePi 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 Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
 ***********************************************************************
 */

#include "../config.h"
#include "mbselib.h"

#ifdef HAVE_WIRINGPI_H

int			lcdHandle;
unsigned char		lcdbuf[MAX_LCDS][20][4];

struct lcdDataStruct
{
    int bits, rows, cols ;
    int rsPin, strbPin ;
    int dataPins [8] ;
    int cx, cy ;
};
extern struct lcdDataStruct	*lcds [MAX_LCDS];


/*
 * Some LCD functions are extended shadow copies of the wiringPi functions.
 * The difference is that the lcdbuf will be updated with the contents on
 * the hardware display. This copy can then be used for a remote display
 */


/*
 * setBacklight:
 *********************************************************************************
 */

void setBacklight (int value)
{
  pinMode (AF_BACKLIGHT, OUTPUT) ;
  digitalWrite (AF_BACKLIGHT, (value & 1)) ;
}


/*
 * initLCD:
 *********************************************************************************
 */

int initLCD (int cols, int rows)
{
    int	x, y;

    if (!((rows == 1) || (rows == 2) || (rows == 4))) {
    	fprintf (stderr, "rows must be 1, 2 or 4\n") ;
    	return EXIT_FAILURE ;
    }

    if (!((cols == 16) || (cols == 20))) {
    	fprintf (stderr, "cols must be 16 or 20\n") ;
    	return EXIT_FAILURE ;
    }

    pcf8574Setup(AF_BASE, 0x27) ;
    pinMode (AF_RW, OUTPUT) ;
    digitalWrite (AF_RW, LOW) ;        // Not used with wiringPi - always in write mode

    /*
     * The other control pins are initialised with lcdInit ()
     */
    lcdHandle = lcdInit (rows, cols, 4, AF_RS, AF_E, AF_DB4, AF_DB5, AF_DB6, AF_DB7, 0, 0, 0, 0) ;
    if (lcdHandle < 0) {
    	fprintf (stderr, "lcdInit failed\n") ;
    	return -1 ;
    }

    lcdClear (lcdHandle) ;
    for (x = 0; x < 20; x++)
	for (y = 0; y < 4; y++)
	    lcdbuf[lcdHandle][x][y] = ' ';

    setBacklight (1) ;

    return 0 ;
}


void mb_lcdPutchar(const int fd, unsigned char data)
{
    struct lcdDataStruct *lcd = lcds[fd];

    /*
     * Write to our buffer first, then to the wiringPi driver.
     * Writing to wiringPi updates the cursor position.
     */
    lcdbuf[fd][lcd->cx][lcd->cy] = data;
    lcdPutchar(fd, data);
}


void mb_lcdPuts(const int fd, const char *string)
{
    while (*string)
	mb_lcdPutchar (fd, *string++);
}


void mb_lcdClear(const int fd)
{
    int	x, y;

    lcdClear(fd);
    for (x = 0; x < 20; x++)
	for (y = 0; y < 4; y++)
	    lcdbuf[fd][x][y] = ' ';
}


#endif