Molly Emig / GP-20U7

GPS library

GPS.cpp@1:55ded12c9c89, 2016-03-10 (annotated)

Committer:
nliu96
Date:
Thu Mar 10 18:21:41 2016 +0000
Revision:
1:55ded12c9c89
Parent:
0:15611c7938a3
Child:
2:c17f5ba1c3f0
testing

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
nliu96 1:55ded12c9c89 25 Serial pc1(USBTX, USBRX);
nliu96 1:55ded12c9c89 26
simon 0:15611c7938a3 27 GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) {
nliu96 1:55ded12c9c89 28 _gps.baud(4800);
nliu96 1:55ded12c9c89 29
simon 0:15611c7938a3 30 longitude = 0.0;
simon 0:15611c7938a3 31 latitude = 0.0;
simon 0:15611c7938a3 32 }
simon 0:15611c7938a3 33
simon 0:15611c7938a3 34 int GPS::sample() {
simon 0:15611c7938a3 35 float time;
simon 0:15611c7938a3 36 char ns, ew;
simon 0:15611c7938a3 37 int lock;
simon 0:15611c7938a3 38
simon 0:15611c7938a3 39 while(1) {
simon 0:15611c7938a3 40 getline();
simon 0:15611c7938a3 41 // Check if it is a GPGGA msg (matches both locked and non-locked msg)
nliu96 1:55ded12c9c89 42 pc1.printf(msg);
nliu96 1:55ded12c9c89 43 pc1.printf("\n");
nliu96 1:55ded12c9c89 44 wait(5);
simon 0:15611c7938a3 45 if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d", &time, &latitude, &ns, &longitude, &ew, &lock) >= 1) {
simon 0:15611c7938a3 46 if(!lock) {
simon 0:15611c7938a3 47 longitude = 0.0;
simon 0:15611c7938a3 48 latitude = 0.0;
simon 0:15611c7938a3 49 return 0;
simon 0:15611c7938a3 50 } else {
simon 0:15611c7938a3 51 if(ns == 'S') { latitude *= -1.0; }
simon 0:15611c7938a3 52 if(ew == 'W') { longitude *= -1.0; }
simon 0:15611c7938a3 53 float degrees = trunc(latitude / 100.0f);
simon 0:15611c7938a3 54 float minutes = latitude - (degrees * 100.0f);
simon 0:15611c7938a3 55 latitude = degrees + minutes / 60.0f;
simon 0:15611c7938a3 56 degrees = trunc(longitude / 100.0f * 0.01f);
simon 0:15611c7938a3 57 minutes = longitude - (degrees * 100.0f);
simon 0:15611c7938a3 58 longitude = degrees + minutes / 60.0f;
simon 0:15611c7938a3 59 return 1;
simon 0:15611c7938a3 60 }
simon 0:15611c7938a3 61 }
simon 0:15611c7938a3 62 }
simon 0:15611c7938a3 63 }
simon 0:15611c7938a3 64
simon 0:15611c7938a3 65 float GPS::trunc(float v) {
simon 0:15611c7938a3 66 if(v < 0.0) {
simon 0:15611c7938a3 67 v*= -1.0;
simon 0:15611c7938a3 68 v = floor(v);
simon 0:15611c7938a3 69 v*=-1.0;
simon 0:15611c7938a3 70 } else {
simon 0:15611c7938a3 71 v = floor(v);
simon 0:15611c7938a3 72 }
simon 0:15611c7938a3 73 return v;
simon 0:15611c7938a3 74 }
simon 0:15611c7938a3 75
simon 0:15611c7938a3 76 void GPS::getline() {
nliu96 1:55ded12c9c89 77 while(1) {
nliu96 1:55ded12c9c89 78 char a = _gps.getc();
nliu96 1:55ded12c9c89 79 pc1.printf("%c", a);
simon 0:15611c7938a3 80 }
nliu96 1:55ded12c9c89 81 // while(_gps.getc() != '$'); // wait for the start of a line
nliu96 1:55ded12c9c89 82 // for(int i=0; i<256; i++) {
nliu96 1:55ded12c9c89 83 // msg[i] = _gps.getc();
nliu96 1:55ded12c9c89 84 // if(msg[i] == '\r') {
nliu96 1:55ded12c9c89 85 // msg[i] = 0;
nliu96 1:55ded12c9c89 86 // return;
nliu96 1:55ded12c9c89 87 // }
nliu96 1:55ded12c9c89 88 // }
nliu96 1:55ded12c9c89 89 // error("Overflowed message limit");
simon 0:15611c7938a3 90 }