16ELA007 Group 15 / GPS

Works!(ish)

Fork of GPS by Simon Ford

GPS.cpp@1:755c749bfa06, 2017-03-21 (annotated)

Committer:
mbedevilledEgg
Date:
Tue Mar 21 15:38:11 2017 +0000
Revision:
1:755c749bfa06
Parent:
0:15611c7938a3
Child:
2:b2c784b47c84
Works!(ish)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
simon 0:15611c7938a3 1 /* mbed EM-406 GPS Module Library
simon 0:15611c7938a3 2 * Copyright (c) 2008-2010, sford
simon 0:15611c7938a3 3 *
simon 0:15611c7938a3 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
simon 0:15611c7938a3 5 * of this software and associated documentation files (the "Software"), to deal
simon 0:15611c7938a3 6 * in the Software without restriction, including without limitation the rights
simon 0:15611c7938a3 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
simon 0:15611c7938a3 8 * copies of the Software, and to permit persons to whom the Software is
simon 0:15611c7938a3 9 * furnished to do so, subject to the following conditions:
simon 0:15611c7938a3 10 *
simon 0:15611c7938a3 11 * The above copyright notice and this permission notice shall be included in
simon 0:15611c7938a3 12 * all copies or substantial portions of the Software.
simon 0:15611c7938a3 13 *
simon 0:15611c7938a3 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
simon 0:15611c7938a3 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
simon 0:15611c7938a3 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
simon 0:15611c7938a3 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
simon 0:15611c7938a3 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
simon 0:15611c7938a3 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
simon 0:15611c7938a3 20 * THE SOFTWARE.
simon 0:15611c7938a3 21 */
simon 0:15611c7938a3 22
simon 0:15611c7938a3 23 #include "GPS.h"
simon 0:15611c7938a3 24
simon 0:15611c7938a3 25 GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) {
simon 0:15611c7938a3 26 _gps.baud(4800);
simon 0:15611c7938a3 27 longitude = 0.0;
simon 0:15611c7938a3 28 latitude = 0.0;
simon 0:15611c7938a3 29 }
simon 0:15611c7938a3 30
simon 0:15611c7938a3 31 int GPS::sample() {
simon 0:15611c7938a3 32 float time;
simon 0:15611c7938a3 33 char ns, ew;
simon 0:15611c7938a3 34 int lock;
simon 0:15611c7938a3 35
simon 0:15611c7938a3 36 while(1) {
simon 0:15611c7938a3 37 getline();
simon 0:15611c7938a3 38
simon 0:15611c7938a3 39 // Check if it is a GPGGA msg (matches both locked and non-locked msg)
simon 0:15611c7938a3 40 if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d", &time, &latitude, &ns, &longitude, &ew, &lock) >= 1) {
simon 0:15611c7938a3 41 if(!lock) {
simon 0:15611c7938a3 42 longitude = 0.0;
simon 0:15611c7938a3 43 latitude = 0.0;
simon 0:15611c7938a3 44 return 0;
simon 0:15611c7938a3 45 } else {
simon 0:15611c7938a3 46 if(ns == 'S') { latitude *= -1.0; }
simon 0:15611c7938a3 47 if(ew == 'W') { longitude *= -1.0; }
simon 0:15611c7938a3 48 float degrees = trunc(latitude / 100.0f);
simon 0:15611c7938a3 49 float minutes = latitude - (degrees * 100.0f);
simon 0:15611c7938a3 50 latitude = degrees + minutes / 60.0f;
mbedevilledEgg 1:755c749bfa06 51 degrees = trunc(longitude / 100.0f);
simon 0:15611c7938a3 52 minutes = longitude - (degrees * 100.0f);
simon 0:15611c7938a3 53 longitude = degrees + minutes / 60.0f;
simon 0:15611c7938a3 54 return 1;
simon 0:15611c7938a3 55 }
simon 0:15611c7938a3 56 }
simon 0:15611c7938a3 57 }
simon 0:15611c7938a3 58 }
simon 0:15611c7938a3 59
simon 0:15611c7938a3 60 float GPS::trunc(float v) {
simon 0:15611c7938a3 61 if(v < 0.0) {
simon 0:15611c7938a3 62 v*= -1.0;
simon 0:15611c7938a3 63 v = floor(v);
simon 0:15611c7938a3 64 v*=-1.0;
simon 0:15611c7938a3 65 } else {
simon 0:15611c7938a3 66 v = floor(v);
simon 0:15611c7938a3 67 }
simon 0:15611c7938a3 68 return v;
simon 0:15611c7938a3 69 }
simon 0:15611c7938a3 70
simon 0:15611c7938a3 71 void GPS::getline() {
simon 0:15611c7938a3 72 while(_gps.getc() != '$'); // wait for the start of a line
simon 0:15611c7938a3 73 for(int i=0; i<256; i++) {
simon 0:15611c7938a3 74 msg[i] = _gps.getc();
simon 0:15611c7938a3 75 if(msg[i] == '\r') {
simon 0:15611c7938a3 76 msg[i] = 0;
simon 0:15611c7938a3 77 return;
simon 0:15611c7938a3 78 }
simon 0:15611c7938a3 79 }
simon 0:15611c7938a3 80 error("Overflowed message limit");
simon 0:15611c7938a3 81 }