Molly Emig
GPS library
GPS.cpp@0:15611c7938a3, 2010-06-08 (annotated)
- Committer:
- simon
- Date:
- Tue Jun 08 14:10:27 2010 +0000
- Revision:
- 0:15611c7938a3
- Child:
- 1:55ded12c9c89
Who changed what in which revision?
| User | Revision | Line number | New 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; |
| simon | 0:15611c7938a3 | 51 | degrees = trunc(longitude / 100.0f * 0.01f); |
| 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 | } |