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