Darren Ulrich
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");
}
}
}
Revision 1:4b5ffae743c0, committed 2017-02-10
- Comitter:
- trevieze
- Date:
- Fri Feb 10 17:57:45 2017 +0000
- Parent:
- 0:15611c7938a3
- Child:
- 2:dbc6c0789611
- Commit message:
- New interrupt service handler for NMEA library
Changed in this revision
--- a/GPS.cpp Tue Jun 08 14:10:27 2010 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,81 +0,0 @@
-/* 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");
-}
--- a/GPS.h Tue Jun 08 14:10:27 2010 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,57 +0,0 @@
-/* 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 "mbed.h"
-
-#ifndef MBED_GPS_H
-#define MBED_GPS_H
-
-/** A GPS interface for reading from a Globalsat EM-406 GPS Module */
-class GPS {
-public:
-
- /** Create the GPS interface, connected to the specified serial port
- */
- GPS(PinName tx, PinName rx);
-
- /** Sample the incoming GPS data, returning whether there is a lock
- *
- * @return 1 if there was a lock when the sample was taken (and therefore .longitude and .latitude are valid), else 0
- */
- int sample();
-
- /** The longitude (call sample() to set) */
- float longitude;
-
- /** The latitude (call sample() to set) */
- float latitude;
-
-private:
- float trunc(float v);
- void getline();
-
- Serial _gps;
- char msg[256];
-
-};
-
-#endif
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/GPSISR.cpp Fri Feb 10 17:57:45 2017 +0000
@@ -0,0 +1,50 @@
+/* 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 "GPSISR.h"
+
+GPS::GPS(PinName tx, PinName rx, int Baud) : _gps(tx, rx) {
+ _gps.baud(Baud);
+ _gps.attach(this,&GPS::Rx_interrupt, Serial::RxIrq);
+ printf("Interrupt Attached");
+}
+
+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");
+ return;
+}
+
+// Interupt Routine to read in data from serial port
+void GPS::Rx_interrupt(void) {
+ interrupt = 1;
+ rx_in = _gps.getc();
+ interrupt = 0;
+ return;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/GPSISR.h Fri Feb 10 17:57:45 2017 +0000
@@ -0,0 +1,47 @@
+/* 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 "mbed.h"
+
+#ifndef MBED_GPS_H
+#define MBED_GPS_H
+
+/** A GPS interface for reading from a Globalsat EM-406 GPS Module */
+class GPS {
+public:
+
+ /** Create the GPS interface, connected to the specified serial port
+ */
+ GPS(PinName tx, PinName rx, int Baud);
+ //Peripheral
+ Serial _gps;
+ // Setup a serial interrupt function to transmit data
+ void getline();
+ void Rx_interrupt(void);
+ char msg[256];
+ volatile char rx_in;
+ bool interrupt;
+private:
+
+ };
+
+#endif
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/nmea.cpp Fri Feb 10 17:57:45 2017 +0000
@@ -0,0 +1,340 @@
+/*
+ File: nmea.cpp
+ Version: 0.1.0
+ Date: Feb. 23, 2013
+ License: GPL v2
+
+ NMEA GPS content parser
+
+ ****************************************************************************
+ Copyright (C) 2013 Radu Motisan <radu.motisan@gmail.com>
+
+ http://www.pocketmagic.net
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ ****************************************************************************
+ */
+
+#include "nmea.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mbed.h"
+#include <stdint.h>
+#include <math.h>
+#include <ctype.h>
+
+//#include "../uart/uart.h"
+//extern UART uart1;
+
+
+/*
+ * The serial data is assembled on the fly, without using any redundant buffers.
+ * When a sentence is complete (one that starts with $, ending in EOL), all processing is done on
+ * this temporary buffer that we've built: checksum computation, extracting sentence "words" (the CSV values),
+ * and so on.
+ * When a new sentence is fully assembled using the fusedata function, the code calls parsedata.
+ * This function in turn, splits the sentences and interprets the data. Here is part of the parser function,
+ * handling both the $GPRMC NMEA sentence:
+ */
+int NMEA::fusedata(char c) {
+
+ if (c == '$') {
+ m_bFlagRead = true;
+ // init parser vars
+ m_bFlagComputedCks = false;
+ m_nChecksum = 0;
+ // after getting * we start cuttings the received m_nChecksum
+ m_bFlagReceivedCks = false;
+ index_received_checksum = 0;
+ // word cutting variables
+ m_nWordIdx = 0; m_nPrevIdx = 0; m_nNowIdx = 0;
+ }
+
+ if (m_bFlagRead) {
+ // check ending
+ if (c == '\r' || c== '\n') {
+ // catch last ending item too
+ tmp_words[m_nWordIdx][m_nNowIdx - m_nPrevIdx] = 0;
+ m_nWordIdx++;
+ // cut received m_nChecksum
+ tmp_szChecksum[index_received_checksum] = 0;
+ // sentence complete, read done
+ m_bFlagRead = false;
+ // parse
+ parsedata();
+ } else {
+ // computed m_nChecksum logic: count all chars between $ and * exclusively
+ if (m_bFlagComputedCks && c == '*') m_bFlagComputedCks = false;
+ if (m_bFlagComputedCks) m_nChecksum ^= c;
+ if (c == '$') m_bFlagComputedCks = true;
+ // received m_nChecksum
+ if (m_bFlagReceivedCks) {
+ tmp_szChecksum[index_received_checksum] = c;
+ index_received_checksum++;
+ }
+ if (c == '*') m_bFlagReceivedCks = true;
+ // build a word
+ tmp_words[m_nWordIdx][m_nNowIdx - m_nPrevIdx] = c;
+ if (c == ',') {
+ tmp_words[m_nWordIdx][m_nNowIdx - m_nPrevIdx] = 0;
+ m_nWordIdx++;
+ m_nPrevIdx = m_nNowIdx;
+ }
+ else m_nNowIdx++;
+ }
+ }
+ return m_nWordIdx;
+}
+
+
+/*
+ * parse internal tmp_ structures, fused by pushdata, and set the data flag when done
+ */
+void NMEA::parsedata() {
+ int received_cks = 16*digit2dec(tmp_szChecksum[0]) + digit2dec(tmp_szChecksum[1]);
+ //uart1.Send("seq: [cc:%X][words:%d][rc:%s:%d]\r\n", m_nChecksum,m_nWordIdx, tmp_szChecksum, received_cks);
+ // check checksum, and return if invalid!
+ if (m_nChecksum != received_cks) {
+ //m_bFlagDataReady = false;
+ return;
+ }
+ /* $GPGGA
+ * $GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh
+ * ex: $GPGGA,230600.501,4543.8895,N,02112.7238,E,1,03,3.3,96.7,M,39.0,M,,0000*6A,
+ *
+ * WORDS:
+ * 1 = UTC of Position
+ * 2 = Latitude
+ * 3 = N or S
+ * 4 = Longitude
+ * 5 = E or W
+ * 6 = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix)
+ * 7 = Number of satellites in use [not those in view]
+ * 8 = Horizontal dilution of position
+ * 9 = Antenna altitude above/below mean sea level (geoid)
+ * 10 = Meters (Antenna height unit)
+ * 11 = Geoidal separation (Diff. between WGS-84 earth ellipsoid and mean sea level.
+ * -geoid is below WGS-84 ellipsoid)
+ * 12 = Meters (Units of geoidal separation)
+ * 13 = Age in seconds since last update from diff. reference station
+ * 14 = Diff. reference station ID#
+ * 15 = Checksum
+ */
+ if (mstrcmp(tmp_words[0], "$GPGGA") == 0) {
+ // Check GPS Fix: 0=no fix, 1=GPS fix, 2=Dif. GPS fix
+ if (tmp_words[6][0] == '0') {
+ // clear data
+ res_fLatitude = 0;
+ res_fLongitude = 0;
+ m_bFlagDataReady = false;
+ return;
+ }
+ // parse time
+ res_nUTCHour = digit2dec(tmp_words[1][0]) * 10 + digit2dec(tmp_words[1][1]);
+ res_nUTCMin = digit2dec(tmp_words[1][2]) * 10 + digit2dec(tmp_words[1][3]);
+ res_nUTCSec = digit2dec(tmp_words[1][4]) * 10 + digit2dec(tmp_words[1][5]);
+ // parse latitude and longitude in NMEA format
+ res_fLatitude = string2float(tmp_words[2]);
+ res_fLongitude = string2float(tmp_words[4]);
+ // get decimal format
+ if (tmp_words[3][0] == 'S') res_fLatitude *= -1.0;
+ if (tmp_words[5][0] == 'W') res_fLongitude *= -1.0;
+ float degrees = trunc(res_fLatitude / 100.0f);
+ float minutes = res_fLatitude - (degrees * 100.0f);
+ res_fLatitude = degrees + minutes / 60.0f;
+ degrees = trunc(res_fLongitude / 100.0f);
+ minutes = res_fLongitude - (degrees * 100.0f);
+ res_fLongitude = degrees + minutes / 60.0f;
+
+ // parse number of satellites
+ res_nSatellitesUsed = (int)string2float(tmp_words[7]);
+
+ // parse altitude
+ res_fAltitude = string2float(tmp_words[9]);
+
+ // data ready
+ m_bFlagDataReady = true;
+ }
+
+ /* $GPRMC
+ * note: a siRF chipset will not support magnetic headers.
+ * $GPRMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,ddmmyy,x.x,a*hh
+ * ex: $GPRMC,230558.501,A,4543.8901,N,02112.7219,E,1.50,181.47,230213,,,A*66,
+ *
+ * WORDS:
+ * 1 = UTC of position fix
+ * 2 = Data status (V=navigation receiver warning)
+ * 3 = Latitude of fix
+ * 4 = N or S
+ * 5 = Longitude of fix
+ * 6 = E or W
+ * 7 = Speed over ground in knots
+ * 8 = Track made good in degrees True, Bearing This indicates the direction that the device is currently moving in,
+ * from 0 to 360, measured in �azimuth�.
+ * 9 = UT date
+ * 10 = Magnetic variation degrees (Easterly var. subtracts from true course)
+ * 11 = E or W
+ * 12 = Checksum
+ */
+ if (mstrcmp(tmp_words[0], "$GPRMC") == 0) {
+ // Check data status: A-ok, V-invalid
+ if (tmp_words[2][0] == 'V') {
+ // clear data
+ res_fLatitude = 0;
+ res_fLongitude = 0;
+ m_bFlagDataReady = false;
+ return;
+ }
+ // parse time
+ res_nUTCHour = digit2dec(tmp_words[1][0]) * 10 + digit2dec(tmp_words[1][1]);
+ res_nUTCMin = digit2dec(tmp_words[1][2]) * 10 + digit2dec(tmp_words[1][3]);
+ res_nUTCSec = digit2dec(tmp_words[1][4]) * 10 + digit2dec(tmp_words[1][5]);
+ // parse latitude and longitude in NMEA format
+ res_fLatitude = string2float(tmp_words[3]);
+ res_fLongitude = string2float(tmp_words[5]);
+ // get decimal format
+ if (tmp_words[4][0] == 'S') res_fLatitude *= -1.0;
+ if (tmp_words[6][0] == 'W') res_fLongitude *= -1.0;
+ float degrees = trunc(res_fLatitude / 100.0f);
+ float minutes = res_fLatitude - (degrees * 100.0f);
+ res_fLatitude = degrees + minutes / 60.0f;
+ degrees = trunc(res_fLongitude / 100.0f);
+ minutes = res_fLongitude - (degrees * 100.0f);
+ res_fLongitude = degrees + minutes / 60.0f;
+ //parse speed
+ // The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour
+ res_fSpeed = string2float(tmp_words[7]);
+ res_fSpeed /= 1.852; // convert to km/h
+ // parse bearing
+ res_fBearing = string2float(tmp_words[8]);
+ // parse UTC date
+ res_nUTCDay = digit2dec(tmp_words[9][0]) * 10 + digit2dec(tmp_words[9][1]);
+ res_nUTCMonth = digit2dec(tmp_words[9][2]) * 10 + digit2dec(tmp_words[9][3]);
+ res_nUTCYear = digit2dec(tmp_words[9][4]) * 10 + digit2dec(tmp_words[9][5]);
+
+ // data ready
+ m_bFlagDataReady = true;
+ }
+}
+/*
+ * returns base-16 value of chars '0'-'9' and 'A'-'F';
+ * does not trap invalid chars!
+ */
+int NMEA::digit2dec(char digit) {
+ if (int(digit) >= 65)
+ return int(digit) - 55;
+ else
+ return int(digit) - 48;
+}
+
+/* returns base-10 value of zero-terminated string
+ * that contains only chars '+','-','0'-'9','.';
+ * does not trap invalid strings!
+ */
+float NMEA::string2float(char* s) {
+ long integer_part = 0;
+ float decimal_part = 0.0;
+ float decimal_pivot = 0.1;
+ bool isdecimal = false, isnegative = false;
+
+ char c;
+ while ( ( c = *s++) ) {
+ // skip special/sign chars
+ if (c == '-') { isnegative = true; continue; }
+ if (c == '+') continue;
+ if (c == '.') { isdecimal = true; continue; }
+
+ if (!isdecimal) {
+ integer_part = (10 * integer_part) + (c - 48);
+ }
+ else {
+ decimal_part += decimal_pivot * (float)(c - 48);
+ decimal_pivot /= 10.0;
+ }
+ }
+ // add integer part
+ decimal_part += (float)integer_part;
+
+ // check negative
+ if (isnegative) decimal_part = - decimal_part;
+
+ return decimal_part;
+}
+
+int NMEA::mstrcmp(const char *s1, const char *s2)
+{
+ while((*s1 && *s2) && (*s1 == *s2))
+ s1++,s2++;
+ return *s1 - *s2;
+}
+
+bool NMEA::isdataready() {
+ return m_bFlagDataReady;
+}
+
+int NMEA::getHour() {
+ return res_nUTCHour;
+}
+int NMEA::getMinute() {
+ return res_nUTCMin;
+}
+int NMEA::getSecond() {
+ return res_nUTCSec;
+}
+int NMEA::getDay() {
+ return res_nUTCDay;
+}
+int NMEA::getMonth() {
+ return res_nUTCMonth;
+}
+int NMEA::getYear() {
+ return res_nUTCYear;
+}
+
+float NMEA::getLatitude() {
+ return res_fLatitude;
+}
+
+float NMEA::getLongitude() {
+ return res_fLongitude;
+}
+
+int NMEA::getSatellites() {
+ return res_nSatellitesUsed;
+}
+
+float NMEA::getAltitude() {
+ return res_fAltitude;
+}
+
+float NMEA::getSpeed() {
+ return res_fSpeed;
+}
+
+float NMEA::getBearing() {
+ return res_fBearing;
+}
+
+float NMEA::trunc(float v) {
+ if(v < 0.0) {
+ v*= -1.0;
+ v = floor(v);
+ v*=-1.0;
+ } else {
+ v = floor(v);
+ }
+ return v;
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/nmea.h Fri Feb 10 17:57:45 2017 +0000
@@ -0,0 +1,104 @@
+/*
+ File: nmea.h
+ Version: 0.1.0
+ Date: Feb. 23, 2013
+ License: GPL v2
+
+ NMEA GPS content parser
+
+ ****************************************************************************
+ Copyright (C) 2013 Radu Motisan <radu.motisan@gmail.com>
+
+ http://www.pocketmagic.net
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ ****************************************************************************
+ */
+//#include "../timeout.h"
+
+
+
+class NMEA {
+
+ private:
+ bool m_bFlagRead, // flag used by the parser, when a valid sentence has begun
+ m_bFlagDataReady; // valid GPS fix and data available, user can call reader functions
+ char tmp_words[20][15], // hold parsed words for one given NMEA sentence
+ tmp_szChecksum[15]; // hold the received checksum for one given NMEA sentence
+
+ // will be set to true for characters between $ and * only
+ bool m_bFlagComputedCks ; // used to compute checksum and indicate valid checksum interval (between $ and * in a given sentence)
+ int m_nChecksum ; // numeric checksum, computed for a given sentence
+ bool m_bFlagReceivedCks ; // after getting * we start cuttings the received checksum
+ int index_received_checksum ; // used to parse received checksum
+
+ // word cutting variables
+ int m_nWordIdx , // the current word in a sentence
+ m_nPrevIdx, // last character index where we did a cut
+ m_nNowIdx ; // current character index
+
+ // globals to store parser results
+ float res_fLongitude; // GPRMC and GPGGA
+ float res_fLatitude; // GPRMC and GPGGA
+ unsigned char res_nUTCHour, res_nUTCMin, res_nUTCSec, // GPRMC and GPGGA
+ res_nUTCDay, res_nUTCMonth, res_nUTCYear; // GPRMC
+ int res_nSatellitesUsed; // GPGGA
+ float res_fAltitude; // GPGGA
+ float res_fSpeed; // GPRMC
+ float res_fBearing; // GPRMC
+
+ // the parser, currently handling GPRMC and GPGGA, but easy to add any new sentences
+ void parsedata();
+ // aux functions
+ int digit2dec(char hexdigit);
+ float string2float(char* s);
+ int mstrcmp(const char *s1, const char *s2);
+ float trunc(float v);
+
+ public:
+ // constructor, initing a few variables
+ NMEA() {
+ m_bFlagRead = false; //are we in a sentence?
+ m_bFlagDataReady = false; //is data available?
+ }
+
+ /*
+ * The serial data is assembled on the fly, without using any redundant buffers.
+ * When a sentence is complete (one that starts with $, ending in EOL), all processing is done on
+ * this temporary buffer that we've built: checksum computation, extracting sentence "words" (the CSV values),
+ * and so on.
+ * When a new sentence is fully assembled using the fusedata function, the code calls parsedata.
+ * This function in turn, splits the sentences and interprets the data. Here is part of the parser function,
+ * handling both the $GPRMC NMEA sentence:
+ */
+ int fusedata(char c);
+
+
+ // READER functions: retrieving results, call isdataready() first
+ bool isdataready();
+ int getHour();
+ int getMinute();
+ int getSecond();
+ int getDay();
+ int getMonth();
+ int getYear();
+ float getLatitude();
+ float getLongitude();
+ int getSatellites();
+ float getAltitude();
+ float getSpeed();
+ float getBearing();
+ };
+