Joseph Bradshaw / GPSINT

library for parsing GPS NMEA strings using serial receive interrupt

Fork of GPSINT by Joseph Bradshaw

GPSINT library

Library class for intercepting NMEA-0183 ASCII strings from a GPS using a serial interrupt at 4800 baud, error checking, and parsing using the scanf functions to update object associated variables

include the mbed library with this snippet

// mbed GPS Parse Program, tested using the Trimble Copernicus II
#include "mbed.h"
#include "GPSINT.h"

#define TIMEZONE -4 //Eastern Standard Time

Serial pc(USBTX,USBRX);
GPSINT gps(p28, p27);   //Tx,Rx
DigitalOut led1(LED1);

// ---------------- MAIN ------------------------
int main() {        
    pc.baud(921600);
  
    while(1) {
        if(gps.lock != 0){
            led1=!led1;
            
            int gpsHour = (int)((int)gps.utc_time/10000) + TIMEZONE;
            if(gpsHour < 0)
                gpsHour += 24;
            
            int gpsMin = (int)((int)gps.utc_time/100%100);
            int gpsSec = (int)gps.utc_time % 100;
      
            pc.printf("lock=%d %2d:%02d:%02d  %f %c %f %c\r\n", gps.lock, gpsHour,gpsMin,gpsSec,gps.nmea_longitude, gps.ns, gps.nmea_latitude, gps.ew);
            wait(.9);
        }
        else{
            pc.printf("No Lock\r\n");
            wait(1);    
        }        
    }//while(1)
}//main

Diff: GPSINT.h

Revision:
1:c266b90b4c74
Parent:
0:f3a7d716faea
--- a/GPSINT.h	Sat Nov 01 13:27:11 2014 +0000
+++ b/GPSINT.h	Wed Nov 05 16:43:55 2014 +0000
@@ -1,5 +1,7 @@
-/* GPSINT.h
- * Copyright (c) 2014, jbradshaw (20141101)
+/* GPSINT.cpp
+ * jbradshaw (20141101)
+ * GPS functions are work of Tyler Weavers mbed gps library page 
+ * (http://mbed.org/users/tylerjw/code/GPS/file/39d75e44b214/GPS.cpp)
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -46,10 +48,10 @@
      * @param gps - Serial port pins attached to the gps
      */ 
     GPSINT(PinName tx, PinName rx);
-    int nmea_validate(char *nmeastr);
-    void parseGPSString(char *GPSstrParse);
-    void GPSSerialRecvInterrupt(void);
-    float nmea_to_dec(float deg_coord, char nsew);
+    int nmea_validate(char *nmeastr);               //runs the checksum calculation on the GPS NMEA string
+    void parseGPSString(char *GPSstrParse);         //uses scanf to parse NMEA string into variables
+    void GPSSerialRecvInterrupt(void);              //fills temprpary buffer for processing
+    float nmea_to_dec(float deg_coord, char nsew);  //convert nmea format to decimal format
     float calc_course_to(float pointLat, float pontLong);
     double calc_dist_to_mi(float pointLat, float pontLong);
     double calc_dist_to_ft(float pointLat, float pontLong);