MTK3339.h

00001 #ifndef MTK3339_H
00002 #define MTK3339_H
00003 
00004 /** 
00005  * An interface to the MTK3339 GPS module.
00006  */
00007 class MTK3339 {
00008 public:
00009 
00010 
00011     enum NmeaSentence {
00012         NmeaInvalid = 0,
00013         NmeaGga = 0x01,
00014 //        NmeaGsa = 0x02,
00015 //        NmeaGsv = 0x04,
00016 //        NmeaRmc = 0x08,
00017         NmeaVtg = 0x10
00018     };
00019        
00020     struct GgaType {
00021         /** UTC time - hours */
00022         int hours;
00023         /** UTC time - minutes */
00024         int minutes;
00025         /** UTC time - seconds */
00026         int seconds;
00027         /** UTC time - milliseconds */
00028         int milliseconds;
00029         
00030         /** The latitude in ddmm.mmmm format (d = degrees, m = minutes) */
00031         double latitude;  
00032         /** The longitude in dddmm.mmmm format */
00033         double longitude;
00034         /** North / South indicator */
00035         char nsIndicator;
00036         /** East / West indicator */
00037         char ewIndicator;    
00038        
00039         /** 
00040          * Position indicator: 
00041          * 0 = Fix not available
00042          * 1 = GPS fix
00043          * 2 = Differential GPS fix
00044          */
00045         int fix;  
00046     
00047         /** Number of used satellites */
00048         int satellites;
00049         /** Horizontal Dilution of Precision */
00050         double hdop;
00051         /** antenna altitude above/below mean sea-level */
00052         double altitude;
00053         /** geoidal separation */
00054         double geoidal;        
00055     };
00056     
00057     struct VtgType {
00058         /** heading in degrees */
00059         double course;
00060         /** speed in Knots */
00061         double speedKnots;
00062         /** Speed in kilometer  per hour */
00063         double speedKmHour;
00064         /** 
00065          * Mode
00066          * A = Autonomous mode
00067          * D = Differential mode
00068          * E = Estimated mode
00069          */
00070         char mode;
00071     };
00072 
00073     /** 
00074      * Create an interface to the MTK3339 GPS module
00075      *
00076      * @param tx UART TX line pin
00077      * @param rx UART RX line pin
00078      */
00079     MTK3339(PinName tx, PinName rx);
00080          
00081     /** 
00082      * Start to read data from the GPS module.
00083      * 
00084      * @param fptr A pointer to a void function that will be called when there 
00085      * is data available. 
00086      * @param mask specifies which sentence types (NmeaSentence) that are of 
00087      * interest. The callback function will only be called for messages 
00088      * specified in this mask.
00089      */     
00090     void start(void (*fptr)(void), int mask);
00091 
00092     /** 
00093      * Start to read data from the GPS module.
00094      * 
00095      * @param tptr pointer to the object to call the member function on
00096      * @param mptr pointer to the member function to be called
00097      * @param mask specifies which sentence types (NmeaSentence) that are of 
00098      * interest. The member function will only be called for messages 
00099      * specified in this mask.
00100      */        
00101     template<typename T>
00102     void start(T* tptr, void (T::*mptr)(void), int mask) {
00103         if((mptr != NULL) && (tptr != NULL) && mask) {
00104             _dataCallback.attach(tptr, mptr);
00105             _sentenceMask = mask;
00106             _serial.attach(this, &MTK3339::uartIrq, Serial::RxIrq);            
00107         }
00108     }    
00109     
00110     /** 
00111      * Stop to read data from GPS module
00112      */
00113     void stop();
00114     
00115     /** 
00116      * Get the type of the data reported in available data callback.
00117      * This method will only return a valid type when called within the
00118      * callback. 
00119      */    
00120     NmeaSentence getAvailableDataType();
00121 
00122     /**
00123      * Get latitude in degrees (decimal format)
00124      */    
00125     double getLatitudeAsDegrees();
00126     /**
00127      * Get longitude in degrees (decimal format)
00128      */    
00129     double getLongitudeAsDegrees();
00130 
00131     /**
00132      * Time, position and fix related data
00133      */
00134     GgaType gga;
00135     
00136     /**
00137      * Course and speed information relative to ground
00138      */
00139     VtgType vtg;
00140 
00141 
00142 private:
00143 
00144     enum PrivConstants {
00145         MTK3339_BUF_SZ = 255
00146     };
00147     
00148     enum DataState {
00149         StateStart = 0,
00150         StateData
00151     };
00152     
00153     FunctionPointer _dataCallback;
00154     char _buf[MTK3339_BUF_SZ];
00155     int _bufPos;
00156     DataState _state;
00157     int _sentenceMask;
00158     NmeaSentence _availDataType;
00159     
00160     Serial _serial;
00161 
00162     
00163     void parseGGA(char* data, int dataLen);
00164     void parseVTG(char* data, int dataLen);   
00165     void parseData(char* data, int len);
00166     void uartIrq();
00167 
00168 
00169 };
00170 
00171 #endif
00172