160 lines
4.1 KiB
C
160 lines
4.1 KiB
C
/*
|
|
* Serial LPT driver module for Hitachi HD44780 based LCD displays by
|
|
* Andrew McMeikan. The LCD is operated in it's 4 bit-mode through a
|
|
* 4094 shift register and supports a keypad.
|
|
*
|
|
* Copyright (c) 1999 Andrew McMeikan <andrewm@engineer.com>
|
|
* modular driver 1999 Benjamin Tse <blt@Comports.com>
|
|
*
|
|
* Full connection details at http://members.xoom.com/andrewmuck/LCD.htm
|
|
*
|
|
* printer port 4094/LCD
|
|
* D2 (4) EN (6 - LCD)
|
|
* D3 (5) D (2 - 4094)
|
|
* D4 (6) CLK (3 - 4094)
|
|
* +Vcc OE, STR (15, 1 - 4094)
|
|
* D7 (9) EN2 (6 - LCD2) (optional)
|
|
*
|
|
* 4094 LCD
|
|
* Q1 (4) D4 (11)
|
|
* Q2 (5) D5 (12)
|
|
* Q3 (6) D6 (13)
|
|
* Q4 (7) D7 (14)
|
|
* Q6 (13) RS (4)
|
|
* Gnd nRW (5)
|
|
*
|
|
* This file is released under the GNU General Public License. Refer to the
|
|
* COPYING file distributed with this package.
|
|
*/
|
|
|
|
#include "hd44780-serialLpt.h"
|
|
#include "port.h"
|
|
|
|
// Hardware specific functions
|
|
void lcdserLpt_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch);
|
|
|
|
static char lcdserLpt_HD44780_getkey (void);
|
|
void rawshift (unsigned char r);
|
|
void shiftreg (unsigned char displayID, unsigned char r);
|
|
|
|
#define RS 16
|
|
#define LCDDATA 8
|
|
#define LCDCLOCK 16
|
|
#define EN1 4
|
|
#define EN2 32
|
|
|
|
static unsigned int lp;
|
|
static char lastkey = 0;
|
|
|
|
// Initialisation
|
|
int
|
|
hd_init_serialLpt (HD44780_functions * hd44780_functions, lcd_logical_driver * driver, char *args, unsigned int port)
|
|
{
|
|
int displayID = EN1 | EN2;
|
|
|
|
lp = port;
|
|
|
|
hd44780_functions->senddata = lcdserLpt_HD44780_senddata;
|
|
|
|
// TODO: enable keypad only if specified on command line
|
|
driver->getkey = lcdserLpt_HD44780_getkey;
|
|
|
|
// setup the lcd in 4 bit mode
|
|
shiftreg (displayID, 3);
|
|
hd44780_functions->uPause (4100);
|
|
|
|
shiftreg (displayID, 3);
|
|
hd44780_functions->uPause (100);
|
|
|
|
shiftreg (displayID, 3);
|
|
hd44780_functions->uPause (40);
|
|
|
|
shiftreg (displayID, 2);
|
|
hd44780_functions->uPause (40);
|
|
|
|
// set display type functions
|
|
lcdserLpt_HD44780_senddata (0, RS_INSTR, FUNCSET | IF_4BIT | TWOLINE | SMALLCHAR);
|
|
// clear
|
|
lcdserLpt_HD44780_senddata (0, RS_INSTR, CLEAR);
|
|
hd44780_functions->uPause (1600);
|
|
// Now turn on the display
|
|
lcdserLpt_HD44780_senddata (displayID, RS_INSTR, ONOFFCTRL | DISPON | CURSOROFF | CURSORNOBLINK);
|
|
hd44780_functions->uPause (1600);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
lcdserLpt_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch)
|
|
{
|
|
unsigned char dispID = 0, portControl = 0, h = ch >> 4, l = ch & 15;
|
|
|
|
if (displayID == 1)
|
|
dispID |= EN1;
|
|
else if (displayID == 2)
|
|
dispID |= EN2;
|
|
else
|
|
dispID |= EN1 | EN2;
|
|
|
|
if (flags == RS_DATA)
|
|
portControl = RS;
|
|
else
|
|
portControl = 0;
|
|
|
|
shiftreg (displayID, flags | portControl | h);
|
|
shiftreg (displayID, flags | portControl | l);
|
|
|
|
/* TODO: instead of delay read keys here */
|
|
}
|
|
|
|
char
|
|
lcdserLpt_HD44780_getkey ()
|
|
{
|
|
// TODO: a keypad scan that does not use shift register
|
|
// define a key table
|
|
char keytr[] = "ABCDEFGH";
|
|
int n;
|
|
|
|
rawshift (0); //send all line on shift register low
|
|
hd44780_functions->uPause (1);
|
|
if ((port_in (lp + 1) & 32) == 0) //test if line back is low - if not return(0)
|
|
{ //else
|
|
//start walking a single zero across the eight lines
|
|
for (n = 7; n >= 0; n--) {
|
|
rawshift (255 - (1 << n));
|
|
hd44780_functions->uPause (1);
|
|
|
|
if ((port_in (lp + 1) & 32) == 0) // check if line back is low if yes debounce
|
|
{
|
|
if (lastkey == keytr[n])
|
|
return (0);
|
|
// printf("key is %c %d\n",keytr[n],n);
|
|
lastkey = keytr[n];
|
|
return (keytr[n]); //return correct key code.
|
|
}
|
|
}
|
|
} //else fall out and return(0) [too transient a keypress]
|
|
lastkey = 0;
|
|
return (0);
|
|
}
|
|
|
|
/* this function sends r out onto the shift register */
|
|
void
|
|
rawshift (unsigned char r)
|
|
{
|
|
int i;
|
|
for (i = 7; i >= 0; i--) { /* MSB first */
|
|
port_out (lp, ((r >> i) & 1) * LCDDATA); /*set up data */
|
|
port_out (lp, (((r >> i) & 1) * LCDDATA) | LCDCLOCK); /*rising edge of clock */
|
|
}
|
|
}
|
|
|
|
// displayID = value on parallel port to toggle the correct display
|
|
void
|
|
shiftreg (unsigned char displayID, unsigned char r)
|
|
{
|
|
rawshift (r);
|
|
port_out (lp, displayID); //latch it, to correct display
|
|
port_out (lp, 0);
|
|
}
|