lcdproc/server/drivers/hd44780-4bit.c

/*
 * 4-bit driver module for Hitachi HD44780 based LCD displays.
 * The LCD is operated in it's 4 bit-mode to be connected to a single
 * 8 bit-port. 
 *
 * Copyright (c)  2000, 1999, 1995 Benjamin Tse <blt@Comports.com>
 *		  1999 Andrew McMeikan <andrewm@engineer.com>
 *		  1998 Richard Rognlie <rrognlie@gamerz.net>
 *		  1997 Matthias Prinke <m.prinke@trashcan.mcnet.de>
 *
 * The connections are:
 * printer port	  LCD
 * D0 (2)      	  D4 (11)
 * D1 (3)	  D5 (12)
 * D2 (4)	  D6 (13)
 * D3 (5)	  D7 (14)
 * D4 (6)	  RS (4)
 * D5 (7)	  RW (5) (LCD3 - 6) (optional - pull all LCD RW low)
 * D6 (8)	  EN (6)
 * D7 (9)	  EN2 (LCD2 - 6) (optional)
 *
 * Extended interface (including LCD3 above)
 * STR (1)	  EN4
 * LF (14)	  EN5
 * INIT (16)	  EN6
 * SEL (17)	  EN7
 *
 * Added support for up to 7 LCDs Jan 2000, Benjamin Tse
 * Created modular driver Dec 1999, Benjamin Tse <blt@Comports.com>
 *
 * Based on Matthias Prinke's <m.prinke@trashcan.mcnet.de> lcd4.c module
 * in lcdstat. This was in turn based on Benjamin Tse's lcdtime package
 * which uses the LCD controller in its 8-bit mode.
 *
 * This file is released under the GNU General Public License. Refer to the
 * COPYING file distributed with this package.
 */

#include "hd44780-4bit.h"
#include "port.h"

#include "../../shared/str.h"
#include <sys/perm.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

// Generally, any function that accesses the LCD control lines needs to be
// implemented separately for each HW design. This is typically just
// HD44780_senddata

void lcdstat_HD44780_senddata(unsigned char displayID, 
			      unsigned char flags, 
			      unsigned char ch);


#define RS 	0x10
#define RW 	0x20
#define EN1 	0x40
#define EN2	0x80
#define EN3	0x20

static unsigned char EnMask[] = { EN1, EN2, EN3, STRB, LF, INIT, SEL };
static int EnMaskSize = sizeof(EnMask) / sizeof(unsigned char);

static unsigned int lptPort;
static int extIF = 0;		// non-zero if extended interface

// initialisation function
int hd_init_4bit(HD44780_functions *hd44780_functions, 
		 lcd_logical_driver *driver, 
		 char *args, 
		 unsigned int port)
{
  // TODO: remove magic numbers below
  char *argv[64];
  int argc;
  int i;
  int displayID = EN1 | EN2;

  lptPort = port;

  hd44780_functions->senddata   = lcdstat_HD44780_senddata;

  // parse command-line arguments
  argc = get_args(argv, args, 64);

  for (i = 0; i < argc; ++i)
  {
    if (strcmp(argv[i], "-e") == 0 ||
	strcmp(argv[i], "--extended") == 0)
    {
      extIF = 1;
      if ((ioperm(port + 2, 1, 255)) == -1) {
	fprintf(stderr, "HD44780_init: failed (%s)\n", strerror(errno)); 
	return -1;
      }
    }
  }
      
  // powerup the lcd now
  if (extIF) 
  {
    displayID |= EN3;
    port_out(lptPort + 2, 0 ^ OUTMASK);
  }

  port_out(lptPort, displayID | 0x03);
  if (extIF) port_out(lptPort + 2, 
		      (EnMask[3] | EnMask[4] | EnMask[5] | EnMask[6]) ^ OUTMASK);
  hd44780_functions->uPause(1);
  port_out(lptPort, 0x03);
  if (extIF) port_out(lptPort + 2, 0 ^ OUTMASK);
  hd44780_functions->uPause(4100);

  port_out(lptPort, displayID | 0x03);	
  if (extIF) port_out(lptPort + 2, 
		      (EnMask[3] | EnMask[4] | EnMask[5] | EnMask[6]) ^ OUTMASK);
  hd44780_functions->uPause(1);
  port_out(lptPort, 0x03);
  if (extIF) port_out(lptPort + 2, 0 ^ OUTMASK);
  hd44780_functions->uPause(100);

  port_out(lptPort, displayID | 0x03);
  if (extIF) port_out(lptPort + 2, 
		      (EnMask[3] | EnMask[4] | EnMask[5] | EnMask[6]) ^ OUTMASK);
  hd44780_functions->uPause(1);
  port_out(lptPort, 0x03);
  if (extIF) port_out(lptPort + 2, 0 ^ OUTMASK);
  hd44780_functions->uPause(40);

  // now in 8-bit mode...  set 4-bit mode
  port_out(lptPort,displayID | 0x02);
  if (extIF) port_out(lptPort + 2, 
		      (EnMask[3] | EnMask[4] | EnMask[5] | EnMask[6]) ^ OUTMASK);
  hd44780_functions->uPause(1);
  port_out(lptPort, 0x02);
  if (extIF) port_out(lptPort + 2, 0 ^ OUTMASK);
  hd44780_functions->uPause(40);

  common_init(IF_4bit);
  return 0;
}


// lcdstat_HD44780_senddata
void lcdstat_HD44780_senddata(unsigned char displayID, 
			      unsigned char iflags, 
			      unsigned char ch)
{
  unsigned char dispID = 0, flags = 0;
  unsigned char h = (ch >> 4) & 0x0f;	// high and low nibbles
  unsigned char l = ch & 0x0f;

  if (iflags == RS_INSTR)
    flags = 0;
  else //if (iflags == RS_DATA)
    flags = RS;

  if (displayID <= 3)
  {
    if (displayID == 0)
      dispID = EnMask[0] | EnMask[1] | EnMask[2];
    else
      dispID = EnMask[displayID - 1];

    port_out(lptPort, flags | h);
    hd44780_functions->uPause(2);
    port_out(lptPort, dispID | flags | h);
    hd44780_functions->uPause(4);
    port_out(lptPort, flags | h);

    port_out(lptPort, dispID | flags | l);
    hd44780_functions->uPause(4);
    port_out(lptPort, flags | l);
  }

  if (extIF && (displayID == 0 || displayID >= 4))
  {
    if (displayID == 0) 
      dispID = EnMask[3] | EnMask[4] | EnMask[5] | EnMask[6];
    else
      dispID = EnMask[(displayID - 1) % EnMaskSize];

    port_out(lptPort, flags | h);
    hd44780_functions->uPause(2);
    port_out(lptPort + 2, dispID ^ OUTMASK);
    hd44780_functions->uPause(4);
    port_out(lptPort + 2, 0 ^ OUTMASK);

    port_out(lptPort, flags | l);
    port_out(lptPort + 2, dispID ^ OUTMASK);
    hd44780_functions->uPause(4);
    port_out(lptPort + 2, 0 ^ OUTMASK);
  }
}