File content as of revision 0:70e7fa78c4ac:
/* mbed EM-406 GPS Module Library
* Copyright (c) 2008-2010, sford
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "GPS.h"
GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) {
_gps.baud(4800);
longitude = 0.0;
latitude = 0.0;
}
int GPS::sample() {
float time;
char ns, ew;
int lock;
while(1) {
getline();
// Check if it is a GPGGA msg (matches both locked and non-locked msg)
if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d", &time, &latitude, &ns, &longitude, &ew, &lock) >= 1) {
if(!lock) {
longitude = 0.0;
latitude = 0.0;
return 0;
} else {
if(ns == 'S') { latitude *= -1.0; }
if(ew == 'W') { longitude *= -1.0; }
float degrees = trunc(latitude / 100.0f);
float minutes = latitude - (degrees * 100.0f);
latitude = degrees + minutes / 60.0f;
degrees = trunc(longitude / 100.0f * 0.01f);
minutes = longitude - (degrees * 100.0f);
longitude = degrees + minutes / 60.0f;
return 1;
}
}
}
}
float GPS::trunc(float v) {
if(v < 0.0) {
v*= -1.0;
v = floor(v);
v*=-1.0;
} else {
v = floor(v);
}
return v;
}
void GPS::getline() {
while(_gps.getc() != '$'); // wait for the start of a line
for(int i=0; i<256; i++) {
msg[i] = _gps.getc();
if(msg[i] == '\r') {
msg[i] = 0;
return;
}
}
error("Overflowed message limit");
}