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freebsd-skq/share/examples/ppi/ppilcd.c
msmith 7f5886c9f1 Sample program using the ppi(4) interface to control LCD modules. 
Currently supports the (very common) Hitachi HD44780, but can be
easily modified to add other chipsets.
1998-01-02 12:10:56 +00:00

440 lines
10 KiB
C
Raw Blame History

/*
* Control LCD module hung off parallel port using the
* ppi 'geek port' interface.
*
* $Id$
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <err.h>
#include <sysexits.h>
/* XXX should be in <machine/> */
#include "ppbconf.h"
#include "ppi.h"
#define debug(lev, fmt, args...) if (debuglevel >= lev) fprintf(stderr, fmt "\n" , ## args);
static void usage(void);
static char *progname;
#define DEFAULT_DEVICE "/dev/ppi0"
/* Driver functions */
static void hd44780_prepare(char *devname, char *options);
static void hd44780_finish(void);
static void hd44780_command(int cmd);
static void hd44780_putc(int c);
/*
* Commands
* Note that unrecognised command escapes are passed through with
* the command value set to the ASCII value of the escaped character.
*/
#define CMD_RESET 0
#define CMD_BKSP 1
#define CMD_CLR 2
#define CMD_NL 3
#define CMD_CR 4
#define CMD_HOME 5
#define MAX_DRVOPT 10 /* maximum driver-specific options */
struct lcd_driver
{
char *l_code;
char *l_name;
char *l_options[MAX_DRVOPT];
void (* l_prepare)(char *name, char *options);
void (* l_finish)(void);
void (* l_command)(int cmd);
void (* l_putc)(int c);
};
static struct lcd_driver lcd_drivertab[] = {
{
"hd44780",
"Hitachi HD44780 and compatibles",
{
"Reset options:",
" 1 1-line display (default 2)",
" B Cursor blink enable",
" C Cursor enable",
" F Large font select",
NULL
},
hd44780_prepare,
hd44780_finish,
hd44780_command,
hd44780_putc
},
{
NULL,
NULL,
{
NULL
},
NULL,
NULL
}
};
static void do_char(struct lcd_driver *driver, char ch);
int debuglevel = 0;
int vflag = 0;
void
main(int argc, char *argv[])
{
extern char *optarg;
extern int optind;
struct lcd_driver *driver = &lcd_drivertab[0];
char *drivertype, *cp;
char *devname = DEFAULT_DEVICE;
char *drvopts = NULL;
int ch, i;
if ((progname = strrchr(argv[0], '/'))) {
progname++;
} else {
progname = argv[0];
}
drivertype = getenv("LCD_TYPE");
while ((ch = getopt(argc, argv, "Dd:f:o:v")) != EOF) {
switch(ch) {
case 'D':
debuglevel++;
break;
case 'd':
drivertype = optarg;
break;
case 'f':
devname = optarg;
break;
case 'o':
drvopts = optarg;
break;
case 'v':
vflag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
/* If an LCD type was specified, look it up */
if (drivertype != NULL) {
driver = NULL;
for (i = 0; lcd_drivertab[i].l_code != NULL; i++) {
if (!strcmp(drivertype, lcd_drivertab[i].l_code)) {
driver = &lcd_drivertab[i];
break;
}
}
if (driver == NULL) {
warnx("LCD driver '%s' not known", drivertype);
usage();
}
}
debug(1, "Driver selected for %s", driver->l_name);
driver->l_prepare(devname, drvopts);
atexit(driver->l_finish);
if (argc > 0) {
debug(2, "reading input from %d argument%s", argc, (argc > 1) ? "s" : "");
for (i = 0; i < argc; i++)
for (cp = argv[i]; *cp; cp++)
do_char(driver, *cp);
} else {
debug(2, "reading input from stdin");
setvbuf(stdin, NULL, _IONBF, 0);
while ((ch = fgetc(stdin)) != EOF)
do_char(driver, (char)ch);
}
exit(EX_OK);
}
static void
usage(void)
{
int i, j;
fprintf(stderr, "usage: %s [-v] [-d drivername] [-f device] [-o options] [args...]\n", progname);
fprintf(stderr, " -D Increase debugging\n");
fprintf(stderr, " -f Specify device, default is '%s'\n", DEFAULT_DEVICE);
fprintf(stderr, " -d Specify driver, one of:\n");
for (i = 0; lcd_drivertab[i].l_code != NULL; i++) {
fprintf(stderr, " %-10s (%s)%s\n",
lcd_drivertab[i].l_code, lcd_drivertab[i].l_name, (i == 0) ? " *default*" : "");
if (lcd_drivertab[i].l_options[0] != NULL) {
for (j = 0; lcd_drivertab[i].l_options[j] != NULL; j++)
fprintf(stderr, " %s\n", lcd_drivertab[i].l_options[j]);
}
}
fprintf(stderr, " -o Specify driver option string\n");
fprintf(stderr, " args Message strings. Embedded escapes supported:\n");
fprintf(stderr, " \\b Backspace\n");
fprintf(stderr, " \\f Clear display, home cursor\n");
fprintf(stderr, " \\n Newline\n");
fprintf(stderr, " \\r Carriage return\n");
fprintf(stderr, " \\R Reset display\n");
fprintf(stderr, " \\v Home cursor\n");
fprintf(stderr, " \\\\ Literal \\\n");
fprintf(stderr, " If args not supplied, strings are read from standard input\n");
exit(EX_USAGE);
}
static void
do_char(struct lcd_driver *driver, char ch)
{
static int esc = 0;
if (esc) {
switch(ch) {
case 'b':
driver->l_command(CMD_BKSP);
break;
case 'f':
driver->l_command(CMD_CLR);
break;
case 'n':
driver->l_command(CMD_NL);
break;
case 'r':
driver->l_command(CMD_CR);
break;
case 'R':
driver->l_command(CMD_RESET);
break;
case 'v':
driver->l_command(CMD_HOME);
break;
case '\\':
driver->l_putc('\\');
break;
default:
driver->l_command(ch);
break;
}
esc = 0;
} else {
if (ch == '\\') {
esc = 1;
} else {
if (vflag || isprint(ch))
driver->l_putc(ch);
}
}
}
/******************************************************************************
* Driver for the Hitachi HD44780. This is probably *the* most common driver
* to be found on one- and two-line alphanumeric LCDs.
*
* This driver assumes the following connections :
*
* Parallel Port LCD Module
* --------------------------------
* Strobe (1) Enable (6)
* Data (2-9) Data (7-14)
* Select(13) RS (4)
* Auto Feed (14) R/W (5)
*
* In addition, power must be supplied to the module, normally with
* a circuit similar to this:
*
* VCC (+5V) O------o-------o--------O Module pin 2
* | | +
* / ---
* \ --- 1uF
* / | -
* \ <-----o--------O Module pin 3
* /
* \
* |
* GND O------o----------------O Module pin 1
*
* The ground line should also be connected to the parallel port, on
* one of the ground pins (eg. pin 25).
*
* Note that the pinning on some LCD modules has the odd and even pins
* arranged as though reversed; check carefully before conecting a module
* as it is possible to toast the HD44780 if the power is reversed.
*/
static int hd_fd;
static u_int8_t hd_cbits;
static int hd_lines = 2;
static int hd_blink = 0;
static int hd_cursor = 0;
static int hd_font = 0;
#define HD_COMMAND SELECTIN
#define HD_DATA 0
#define HD_READ 0
#define HD_WRITE AUTOFEED
#define HD_BF 0x80 /* internal busy flag */
#define HD_ADDRMASK 0x7f /* DDRAM address mask */
#define hd_sctrl(v) {u_int8_t _val; _val = hd_cbits | v; ioctl(hd_fd, PPISCTRL, &_val);}
#define hd_sdata(v) {u_int8_t _val; _val = v; ioctl(hd_fd, PPISDATA, &_val);}
#define hd_gdata(v) ioctl(hd_fd, PPIGDATA, &v)
static void
hd44780_output(int type, int data)
{
debug(3, "%s -> 0x%02x", (type == HD_COMMAND) ? "cmd " : "data", data);
hd_sctrl(type | HD_WRITE | STROBE); /* set direction, address */
hd_sctrl(type | HD_WRITE); /* raise E */
hd_sdata((u_int8_t) data); /* drive data */
hd_sctrl(type | HD_WRITE | STROBE); /* lower E */
}
static int
hd44780_input(int type)
{
u_int8_t val;
hd_sctrl(type | HD_READ | STROBE); /* set direction, address */
hd_sctrl(type | HD_READ); /* raise E */
hd_gdata(val); /* read data */
hd_sctrl(type | HD_READ | STROBE); /* lower E */
debug(3, "0x%02x -> %s", val, (type == HD_COMMAND) ? "cmd " : "data");
return(val);
}
static void
hd44780_prepare(char *devname, char *options)
{
char *cp = options;
if ((hd_fd = open(devname, O_RDWR, 0)) == -1)
err(EX_OSFILE, "can't open '%s'", devname);
/* parse options */
while (cp && *cp) {
switch (*cp++) {
case '1':
hd_lines = 1;
break;
case 'B':
hd_blink = 1;
break;
case 'C':
hd_cursor = 1;
break;
case 'F':
hd_font = 1;
break;
default:
errx(EX_USAGE, "hd44780: unknown option code '%c'", *(cp-1));
}
}
/* Put LCD in idle state */
if (ioctl(hd_fd, PPIGCTRL, &hd_cbits)) /* save other control bits */
err(EX_IOERR, "ioctl PPIGCTRL failed (not a ppi device?)");
hd_cbits &= ~(STROBE | SELECTIN | AUTOFEED); /* set strobe, RS, R/W low */
debug(2, "static control bits 0x%x", hd_cbits);
hd_sctrl(STROBE);
hd_sdata(0);
}
static void
hd44780_finish(void)
{
close(hd_fd);
}
static void
hd44780_command(int cmd)
{
u_int8_t val;
switch (cmd) {
case CMD_RESET: /* full manual reset and reconfigure as per datasheet */
debug(1, "hd44780: reset to %d lines, %s font,%s%s cursor",
hd_lines, hd_font ? "5x10" : "5x7", hd_cursor ? "" : " no", hd_blink ? " blinking" : "");
val = 0x30;
if (hd_lines == 2)
val |= 0x08;
if (hd_font)
val |= 0x04;
hd44780_output(HD_COMMAND, val);
usleep(10000);
hd44780_output(HD_COMMAND, val);
usleep(1000);
hd44780_output(HD_COMMAND, val);
usleep(1000);
val = 0x08; /* display off */
hd44780_output(HD_COMMAND, val);
usleep(1000);
val |= 0x04; /* display on */
if (hd_cursor)
val |= 0x02;
if (hd_blink)
val |= 0x01;
hd44780_output(HD_COMMAND, val);
usleep(1000);
hd44780_output(HD_COMMAND, 0x06); /* shift cursor by increment */
usleep(1000);
/* FALLTHROUGH */
case CMD_CLR:
hd44780_output(HD_COMMAND, 0x01);
usleep(2000);
break;
case CMD_BKSP:
hd44780_output(HD_DATA, 0x10); /* shift cursor left one */
break;
case CMD_NL:
if (hd_lines == 2)
hd44780_output(HD_COMMAND, 0xc0); /* beginning of second line */
break;
case CMD_CR:
/* XXX will not work in 4-line mode, or where readback fails */
val = hd44780_input(HD_COMMAND) & 0x3f; /* mask character position, save line pos */
hd44780_output(HD_COMMAND, 0x80 | val);
break;
case CMD_HOME:
hd44780_output(HD_COMMAND, 0x02);
usleep(2000);
break;
default:
if (isprint(cmd)) {
warnx("unknown command %c", cmd);
} else {
warnx("unknown command 0x%x", cmd);
}
}
usleep(40);
}
static void
hd44780_putc(int c)
{
hd44780_output(HD_DATA, c);
usleep(40);
}
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