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#include <u.h>
#include <libc.h>
#include "dat.h"
char *serial = "/dev/eia0";
int ttyfd, ctlfd, debug;
int baud = Baud;
char *baudstr = "b%dd1r1pns1l8i1w5";
Place where = {-(74.0 + 23.9191/60.0), 40.0 + 41.1346/60.0};
void setline(void);
void evermore80(Place, int);
void evermore89(int);
void evermore8e(void);
void
setline(void){
char *serialctl;
serialctl = smprint("%sctl", serial);
if((ttyfd = open(serial, ORDWR)) < 0)
sysfatal("%s: %r", serial);
if((ctlfd = open(serialctl, OWRITE)) >= 0){
if(fprint(ctlfd, baudstr, baud) < 0)
sysfatal("%s: %r", serialctl);
}
free(serialctl);
}
enum {
GGAon = 0x01,
GLLon = 0x02,
GSAon = 0x04,
GSVon = 0x08,
RMCon = 0x10,
VTGon = 0x20,
CRCon = 0x40,
EMTon = 0x80
};
char*
putbyte(char *s, int v)
{
*s++ = v;
if((v & 0xff) == 0x10)
*s++ = v;
return s;
}
char*
putshort(char *s, int v)
{
s = putbyte(s, v);
s = putbyte(s, v >> 8);
return s;
}
char*
putlong(char *s, long v)
{
s = putbyte(s, v);
s = putbyte(s, v >> 8);
s = putbyte(s, v >> 16);
s = putbyte(s, v >> 24);
return s;
}
void
evermoresend(char *body, int l)
{
char buf[8], *s;
int crc, i;
s = buf;
*s++ = 0x10; /* DCE */
*s++ = 0x02; /* STX */
s = putbyte(s, l); /* length */
write(ttyfd, buf, s-buf); /* write header */
write(ttyfd, body, l); /* write body */
crc = 0;
for(i = 0; i < l; i++)
crc += body[i]; /* calculate crc */
s = buf;
s = putbyte(s, crc); /* checksum */
*s++ = 0x10; /* DCE */
*s++ = 0x03; /* ETX */
write(ttyfd, buf, s-buf); /* write trailer */
}
void
evermore80(Place pl, int baud)
{
char buf[32], *s;
long now, seconds, week;
fprint(2, "Evermore80");
time(&now);
seconds = now - 315964800;
week = (seconds / (7*24*3600));
seconds = seconds % (7*24*3600);
s = buf;
s = putbyte(s, 0x80); /* message ID */
s = putshort(s, week); /* week number */
s = putlong(s, seconds*100); /* seconds */
s = putshort(s, pl.lat*10.0); /* latitude tenths degree */
s = putshort(s, pl.lon*10.0); /* longitude tenths degree */
s = putshort(s, 100); /* altitude meters */
s = putshort(s, 0); /* datumn ID */
s = putbyte(s, 2); /* warm start */
s = putbyte(s, GGAon|GSAon|GSVon|RMCon|CRCon);
switch(baud){
case 4800: s = putbyte(s, 0); break;
case 9600: s = putbyte(s, 1); break;
case 19200: s = putbyte(s, 2); break;
case 38400: s = putbyte(s, 3); break;
default:
sysfatal("Illegal baud rate");
}
evermoresend(buf, s - buf);
fprint(2, "\n");
}
void
evermore89(int baud)
{
char buf[32], *s;
fprint(2, "Evermore89");
s = buf;
s = putbyte(s, 0x89); /* message ID */
s = putbyte(s, 0x01); /* set main serial port */
switch(baud){
case 4800: s = putbyte(s, 0x00); break;
case 9600: s = putbyte(s, 0x01); break;
case 19200: s = putbyte(s, 0x02); break;
case 38400: s = putbyte(s, 0x03); break;
default:
sysfatal("illegal baud rate %d", baud);
}
evermoresend(buf, s - buf);
fprint(2, "\n");
}
void
evermore8e(void)
{
char buf[32], *s;
fprint(2, "Evermore8e");
s = buf;
s = putbyte(s, 0x8e); /* message ID */
s = putbyte(s, GGAon|GSAon|GSVon|RMCon); /* all messages except GLL and VTG */
s = putbyte(s, 0x01); /* checksum on */
s = putbyte(s, 0x01); /* GGA update rate */
s = putbyte(s, 0x0b); /* GLL update rate */
s = putbyte(s, 0x0a); /* GSA update rate */
s = putbyte(s, 0x14); /* GSV update rate */
s = putbyte(s, 0x08); /* RMC update rate */
s = putbyte(s, 0x0d); /* VTG update rate */
evermoresend(buf, s - buf);
fprint(2, "\n");
}
void
main(int argc, char*argv[])
{
char *p;
Place pl;
int newbaud;
newbaud = -1;
pl = nowhere;
ARGBEGIN {
default:
fprint(2, "usage: %s [-b baud] [-d device] [-l longitude latitude] [-n newbaud]\n", argv0);
exits("usage");
case 'D':
debug++;
break;
case 'b':
baud = strtol(ARGF(), nil, 0);
break;
case 'd':
serial = ARGF();
break;
case 'l':
p = ARGF();
if(strtolatlon(p, &p, &pl) < 0)
sysfatal("bad position");
while(*p == ' ' || *p == '\t' || *p == '\n')
p++;
if(*p == '\0')
p = ARGF();
if (strtolatlon(p, &p, &pl) < 0)
sysfatal("bad position");
while(*p == ' ' || *p == '\t' || *p == '\n')
p++;
if(*p != '\0')
sysfatal("trailing gunk in position");
where = pl;
break;
case 'n':
newbaud = strtol(ARGF(), nil, 0);
break;
} ARGEND
if(newbaud < 0)
newbaud = baud;
fmtinstall('L', placeconv);
print("Initializing GPS to %d baud, at %L, time %s\n",
newbaud, where, ctime(time(nil)));
setline();
evermore80(where, newbaud);
}
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