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;


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

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


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

int initLCD (int cols, int rows)
{
  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 ;
  }

  wiringPiSetupSys () ;
  pcf8574Setup (AF_BASE, 0x27) ;

  setBacklight (1) ;

  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) ;
  return 0 ;
}

#endif