102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/*
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* 8-bit driver module for Hitachi HD44780 based LCD displays.
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* The LCD is operated in it's 8 bit-mode to be connected to a single
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* PC parallel port.
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*
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* Copyright (c) 1999, 1995 Benjamin Tse <blt@Comports.com>
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*
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* The connections are:
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* printer port LCD
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* D0 (2) D0 (7)
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* D1 (3) D1 (8)
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* D2 (4) D2 (9)
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* D3 (5) D3 (10)
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* D4 (6) D4 (11)
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* D5 (7) D5 (12)
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* D6 (8) D6 (13)
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* D7 (9) D7 (14)
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* nSEL (17) -
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* nSTRB (1) RS (4)
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* nLF (14) RW (5) (LCD2 - 6) (optional - pull all LCD RW low)
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* INIT (16) EN (6)
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*
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* Created modular driver Dec 1999, Benjamin Tse <blt@Comports.com>
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*
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* Based on the code in the lcdtime package which uses the LCD
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* controller in its 8-bit mode.
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*
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* This file is released under the GNU General Public License. Refer to the
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* COPYING file distributed with this package.
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*/
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#include "hd44780-ext8bit.h"
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#include "port.h"
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#include "lcd_sem.h"
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#include <sys/perm.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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// Generally, any function that accesses the LCD control lines needs to be
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// implemented separately for each HW design. This is typically (but not
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// restricted to):
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// HD44780_senddata
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void lcdtime_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch);
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#define nRS nSTRB
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#define nRW nLF
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#define EN1 INIT
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#define METER_OFF nSEL
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#define SETUPLCD (METER_OFF | nRS)
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#define CTRL (nRW | METER_OFF | nRS)
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#define CHAR (nRW | METER_OFF)
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static unsigned int lptPort;
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static int semid;
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// initialise the driver
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int
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hd_init_ext8bit (HD44780_functions * hd44780_functions, lcd_logical_driver * driver, char *args, unsigned int port)
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{
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lptPort = port;
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semid = sem_get ();
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hd44780_functions->senddata = lcdtime_HD44780_senddata;
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if ((ioperm (port + 2, 1, 255)) == -1) {
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fprintf (stderr, "HD44780_init: failed (%s)\n", strerror (errno));
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return -1;
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}
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common_init (IF_8bit);
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return 0;
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}
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// lcdtime_HD44780_senddata
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void
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lcdtime_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch)
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{
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unsigned char dispID = 0, portControl;
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if (displayID == 1)
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dispID |= EN1;
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else //if (displayID == 0)
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dispID |= EN1;
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if (flags == RS_DATA)
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portControl = CHAR;
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else
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portControl = CTRL;
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sem_wait (semid);
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port_out (lptPort + 2, SETUPLCD);
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port_out (lptPort, ch);
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port_out (lptPort + 2, dispID | portControl);
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hd44780_functions->uPause (1);
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port_out (lptPort + 2, portControl);
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sem_signal (semid);
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}
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