ref: 02a26802ffbd64ebf993119e1599920ffee01ef0
dir: /sys/src/cmd/aux/gps/gpsevermore.c/
#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); }