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lcdproc/server/drivers/hd44780-4bit.c
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/*
* 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>
* 2001 Joris Robijn <joris@robijn.net>
* 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)
*
* Backlight
* D5 (7) backlight (optional, see documentation)
*
* Extended interface (including LCD3 above)
* D5 (7) EN3
* STR (1) EN4
* LF (14) EN5
* INIT (16) EN6
* SEL (17) EN7
*
* Keypad connection (optional):
* Some diodes and resistors are needed, see further documentation.
* printer port keypad
* D0 (2) Y0
* D1 (3) Y1
* D2 (4) Y2
* D3 (5) Y3
* D4 (6) Y4
* D5 (7) Y5
* nSTRB (1) Y6
* nLF (14) Y7
* INIT (16) Y8
* nSEL (17) Y9
* nACK (10) X0
* BUSY (11) X1
* PAPEREND (12 X2
* SELIN (13) X3
* nFAULT (15) X4
*
* 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 "hd44780.h"
#include "lpt-port.h"
#include "port.h"
#include "shared/str.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 (but not
// restricted to):
// HD44780_senddata
// HD44780_readkeypad
void lcdstat_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch);
void lcdstat_HD44780_backlight (unsigned char state);
unsigned char lcdstat_HD44780_readkeypad (unsigned int YData);
#define RS 0x10
#define RW 0x20
#define EN1 0x40
#define EN2 0x80
#define EN3 0x20
#define BL 0x20
// note that the above bits are all meant for the data port of LPT
static unsigned char EnMask[] = { EN1, EN2, EN3, STRB, LF, INIT, SEL };
#define ALLEXT (STRB|LF|INIT|SEL)
// The above bits are on the control port of LPT
static unsigned int lptPort;
static char stuckinputs = 0; // if an input line is stuck, it will be ignored
static char backlight_bit = 0; // default to low to enable three displays
// initialisation function
int
hd_init_4bit (HD44780_functions * hd44780_functions, lcd_logical_driver * driver, char *args, unsigned int port)
{
int enableLines = EN1 | EN2;
// Reserve the port registers
lptPort = port;
port_access(lptPort);
port_access(lptPort+1);
port_access(lptPort+2);
hd44780_functions->senddata = lcdstat_HD44780_senddata;
hd44780_functions->backlight = lcdstat_HD44780_backlight;
hd44780_functions->readkeypad = lcdstat_HD44780_readkeypad;
// powerup the lcd now
if (extIF) {
enableLines |= EN3;
port_out (lptPort + 2, 0 ^ OUTMASK);
}
port_out (lptPort, 0x03);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, enableLines | 0x03);
if (extIF)
port_out (lptPort + 2, ALLEXT ^ OUTMASK);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, 0x03);
if (extIF)
port_out (lptPort + 2, 0 ^ OUTMASK);
hd44780_functions->uPause (4100);
port_out (lptPort, enableLines | 0x03);
if (extIF)
port_out (lptPort + 2, ALLEXT ^ OUTMASK);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, 0x03);
if (extIF)
port_out (lptPort + 2, 0 ^ OUTMASK);
hd44780_functions->uPause (100);
port_out (lptPort, enableLines | 0x03);
if (extIF)
port_out (lptPort + 2, ALLEXT ^ OUTMASK);
if( delayBus ) 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, 0x02);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, enableLines | 0x02);
if (extIF)
port_out (lptPort + 2, ALLEXT ^ OUTMASK);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, 0x02);
if (extIF)
port_out (lptPort + 2, 0 ^ OUTMASK);
hd44780_functions->uPause (40);
// Set up two-line, small character (5x8) mode
hd44780_functions->senddata (0, RS_INSTR, FUNCSET | TWOLINE | SMALLCHAR );
hd44780_functions->uPause (40);
common_init ();
if (have_keypad) {
// Remember which input lines are stuck
stuckinputs = lcdstat_HD44780_readkeypad (0);
}
return 0;
}
// lcdstat_HD44780_senddata
void
lcdstat_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch)
{
unsigned char enableLines = 0, portControl = 0;
unsigned char h = (ch >> 4) & 0x0f; // high and low nibbles
unsigned char l = ch & 0x0f;
if (flags == RS_INSTR)
portControl = 0;
else //if (flags == RS_DATA)
portControl = RS;
portControl |= backlight_bit;
if (displayID <= 3) {
if (displayID == 0)
enableLines = EnMask[0] | EnMask[1] | EnMask[2];
else
enableLines = EnMask[displayID - 1];
port_out (lptPort, portControl | h);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, enableLines | portControl | h);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, portControl | h);
port_out (lptPort, portControl | l);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, enableLines | portControl | l);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort, portControl | l);
}
if (extIF && (displayID == 0 || displayID >= 4)) {
if (displayID == 0)
enableLines = ALLEXT;
else
enableLines = EnMask[(displayID - 1)];
port_out (lptPort, portControl | h);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort + 2, enableLines ^ OUTMASK);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort + 2, 0 ^ OUTMASK);
port_out (lptPort, portControl | l);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort + 2, enableLines ^ OUTMASK);
if( delayBus ) hd44780_functions->uPause (1);
port_out (lptPort + 2, 0 ^ OUTMASK);
}
}
void lcdstat_HD44780_backlight (unsigned char state)
{
backlight_bit = (state?0:0x20); // D5 line
port_out (lptPort, backlight_bit);
}
unsigned char lcdstat_HD44780_readkeypad (unsigned int YData)
{
unsigned char readval;
// 10 bits output or 6 bits if >=3 displays
// Convert the positive logic to the negative logic on the LPT port
port_out (lptPort, ~YData & 0x003F );
if (!extIF) {
port_out (lptPort + 2, ( ((~YData & 0x03C0) << 6 )) ^ OUTMASK);
}
if( delayBus ) hd44780_functions->uPause (1);
// Read inputs
readval = ~ port_in (lptPort + 1) ^ INMASK;
// Put port back into idle state for backlight
port_out (lptPort, backlight_bit);
// And convert value back.
return ( (readval >> 4 & 0x03) | (readval >> 5 & 0x04) | (readval >> 3 & 0x08) | (readval << 1 & 0x10) ) & ~stuckinputs;
}
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