Darren Ulrich / GPSISR

A GPS serial interrupt service routine that has an on the fly nmea parser. Works with a STM32F411RE and a Adafruit GPS logger.

Dependents:   Bicycl_Computer_NUCLEO-F411RE Bicycl_Computer_NUCLEO-L476RG

Fork of GPS by Simon Ford

main.cpp

#include "mbed.h"
#include "GPSISR.h"

#define PIN_RX_GPS      PA_12 //GPS Shield RX pin
#define PIN_TX_GPS      PA_11 //GPS Shield TX pin
Serial pc(USBTX, USBRX);

// Set up serial interrupe service handler for gps characters.
GPS MyGPS(PIN_TX_GPS,PIN_RX_GPS, 9600);
int main()
{
    while (1) {
	if (MyGPS.dataready()) {
					MyGPS.read();
					pc.printf("NMEA has valid data");
					pc.printf("Sats : %d \n", MyGPS.buffer.satellites);
					pc.printf("%d-%d-%d\n", MyGPS.buffer.month, MyGPS.buffer.day, MyGPS.buffer.year);
					pc.printf("%d:%d:%d\n", MyGPS.buffer.hours, MyGPS.buffer.minutes, MyGPS.buffer.seconds);
	}
	else {
                pc.printf("NMEA has no valid data");
	}   
   }  
}

nmea.h@6:f0c13bb7d266, 2017-03-01 (annotated)

Committer:
trevieze
Date:
Wed Mar 01 15:36:05 2017 +0000
Revision:
6:f0c13bb7d266
Parent:
5:c5f700c1e1af 
Math error in GPS speed calculation from Knots to Kilometer. Should be ; 1Kn = 1.85Km

Who changed what in which revision?

UserRevisionLine numberNew contents of line
trevieze 1:4b5ffae743c0 1 /*
trevieze 1:4b5ffae743c0 2 File: nmea.h
trevieze 1:4b5ffae743c0 3 Version: 0.1.0
trevieze 1:4b5ffae743c0 4 Date: Feb. 23, 2013
trevieze 1:4b5ffae743c0 5 License: GPL v2
trevieze 1:4b5ffae743c0 6
trevieze 1:4b5ffae743c0 7 NMEA GPS content parser
trevieze 1:4b5ffae743c0 8
trevieze 1:4b5ffae743c0 9 ****************************************************************************
trevieze 1:4b5ffae743c0 10 Copyright (C) 2013 Radu Motisan <radu.motisan@gmail.com>
trevieze 1:4b5ffae743c0 11
trevieze 1:4b5ffae743c0 12 http://www.pocketmagic.net
trevieze 1:4b5ffae743c0 13
trevieze 1:4b5ffae743c0 14 This program is free software; you can redistribute it and/or modify
trevieze 1:4b5ffae743c0 15 it under the terms of the GNU General Public License as published by
trevieze 1:4b5ffae743c0 16 the Free Software Foundation; either version 2 of the License, or
trevieze 1:4b5ffae743c0 17 (at your option) any later version.
trevieze 1:4b5ffae743c0 18
trevieze 1:4b5ffae743c0 19 This program is distributed in the hope that it will be useful,
trevieze 1:4b5ffae743c0 20 but WITHOUT ANY WARRANTY; without even the implied warranty of
trevieze 1:4b5ffae743c0 21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
trevieze 1:4b5ffae743c0 22 GNU General Public License for more details.
trevieze 1:4b5ffae743c0 23
trevieze 1:4b5ffae743c0 24 You should have received a copy of the GNU General Public License
trevieze 1:4b5ffae743c0 25 along with this program; if not, write to the Free Software
trevieze 1:4b5ffae743c0 26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
trevieze 1:4b5ffae743c0 27 ****************************************************************************
trevieze 1:4b5ffae743c0 28 */
trevieze 1:4b5ffae743c0 29 //#include "../timeout.h"
trevieze 1:4b5ffae743c0 30
trevieze 1:4b5ffae743c0 31
trevieze 1:4b5ffae743c0 32
trevieze 1:4b5ffae743c0 33 class NMEA {
trevieze 1:4b5ffae743c0 34
trevieze 1:4b5ffae743c0 35 private:
trevieze 1:4b5ffae743c0 36 bool m_bFlagRead, // flag used by the parser, when a valid sentence has begun
trevieze 1:4b5ffae743c0 37 m_bFlagDataReady; // valid GPS fix and data available, user can call reader functions
trevieze 1:4b5ffae743c0 38 char tmp_words[20][15], // hold parsed words for one given NMEA sentence
trevieze 1:4b5ffae743c0 39 tmp_szChecksum[15]; // hold the received checksum for one given NMEA sentence
trevieze 1:4b5ffae743c0 40
trevieze 1:4b5ffae743c0 41 // will be set to true for characters between $ and * only
trevieze 1:4b5ffae743c0 42 bool m_bFlagComputedCks ; // used to compute checksum and indicate valid checksum interval (between $ and * in a given sentence)
trevieze 1:4b5ffae743c0 43 int m_nChecksum ; // numeric checksum, computed for a given sentence
trevieze 1:4b5ffae743c0 44 bool m_bFlagReceivedCks ; // after getting * we start cuttings the received checksum
trevieze 1:4b5ffae743c0 45 int index_received_checksum ; // used to parse received checksum
trevieze 1:4b5ffae743c0 46
trevieze 1:4b5ffae743c0 47 // word cutting variables
trevieze 1:4b5ffae743c0 48 int m_nWordIdx , // the current word in a sentence
trevieze 1:4b5ffae743c0 49 m_nPrevIdx, // last character index where we did a cut
trevieze 1:4b5ffae743c0 50 m_nNowIdx ; // current character index
trevieze 1:4b5ffae743c0 51
trevieze 1:4b5ffae743c0 52 // globals to store parser results
trevieze 1:4b5ffae743c0 53 float res_fLongitude; // GPRMC and GPGGA
trevieze 5:c5f700c1e1af 54 char res_clon; // E or W
trevieze 1:4b5ffae743c0 55 float res_fLatitude; // GPRMC and GPGGA
trevieze 5:c5f700c1e1af 56 char res_clat; // N or S
trevieze 1:4b5ffae743c0 57 unsigned char res_nUTCHour, res_nUTCMin, res_nUTCSec, // GPRMC and GPGGA
trevieze 1:4b5ffae743c0 58 res_nUTCDay, res_nUTCMonth, res_nUTCYear; // GPRMC
trevieze 1:4b5ffae743c0 59 int res_nSatellitesUsed; // GPGGA
trevieze 1:4b5ffae743c0 60 float res_fAltitude; // GPGGA
trevieze 1:4b5ffae743c0 61 float res_fSpeed; // GPRMC
trevieze 1:4b5ffae743c0 62 float res_fBearing; // GPRMC
trevieze 1:4b5ffae743c0 63
trevieze 1:4b5ffae743c0 64 // the parser, currently handling GPRMC and GPGGA, but easy to add any new sentences
trevieze 1:4b5ffae743c0 65 void parsedata();
trevieze 1:4b5ffae743c0 66 // aux functions
trevieze 1:4b5ffae743c0 67 int digit2dec(char hexdigit);
trevieze 1:4b5ffae743c0 68 float string2float(char* s);
trevieze 1:4b5ffae743c0 69 int mstrcmp(const char *s1, const char *s2);
trevieze 1:4b5ffae743c0 70 float trunc(float v);
trevieze 1:4b5ffae743c0 71
trevieze 1:4b5ffae743c0 72 public:
trevieze 1:4b5ffae743c0 73 // constructor, initing a few variables
trevieze 1:4b5ffae743c0 74 NMEA() {
trevieze 1:4b5ffae743c0 75 m_bFlagRead = false; //are we in a sentence?
trevieze 1:4b5ffae743c0 76 m_bFlagDataReady = false; //is data available?
trevieze 1:4b5ffae743c0 77 }
trevieze 1:4b5ffae743c0 78
trevieze 1:4b5ffae743c0 79 /*
trevieze 1:4b5ffae743c0 80 * The serial data is assembled on the fly, without using any redundant buffers.
trevieze 1:4b5ffae743c0 81 * When a sentence is complete (one that starts with $, ending in EOL), all processing is done on
trevieze 1:4b5ffae743c0 82 * this temporary buffer that we've built: checksum computation, extracting sentence "words" (the CSV values),
trevieze 1:4b5ffae743c0 83 * and so on.
trevieze 1:4b5ffae743c0 84 * When a new sentence is fully assembled using the fusedata function, the code calls parsedata.
trevieze 1:4b5ffae743c0 85 * This function in turn, splits the sentences and interprets the data. Here is part of the parser function,
trevieze 1:4b5ffae743c0 86 * handling both the $GPRMC NMEA sentence:
trevieze 1:4b5ffae743c0 87 */
trevieze 1:4b5ffae743c0 88 int fusedata(char c);
trevieze 1:4b5ffae743c0 89
trevieze 1:4b5ffae743c0 90
trevieze 1:4b5ffae743c0 91 // READER functions: retrieving results, call isdataready() first
trevieze 1:4b5ffae743c0 92 bool isdataready();
trevieze 1:4b5ffae743c0 93 int getHour();
trevieze 1:4b5ffae743c0 94 int getMinute();
trevieze 1:4b5ffae743c0 95 int getSecond();
trevieze 1:4b5ffae743c0 96 int getDay();
trevieze 1:4b5ffae743c0 97 int getMonth();
trevieze 1:4b5ffae743c0 98 int getYear();
trevieze 1:4b5ffae743c0 99 float getLatitude();
trevieze 5:c5f700c1e1af 100 char getlatc();
trevieze 1:4b5ffae743c0 101 float getLongitude();
trevieze 5:c5f700c1e1af 102 char getlonc();
trevieze 1:4b5ffae743c0 103 int getSatellites();
trevieze 1:4b5ffae743c0 104 float getAltitude();
trevieze 1:4b5ffae743c0 105 float getSpeed();
trevieze 1:4b5ffae743c0 106 float getBearing();
trevieze 1:4b5ffae743c0 107 };
trevieze 1:4b5ffae743c0 108