Revision 3:28a1b60b0f37, committed 2011-04-16

Comitter:

AjK

Date:

Sat Apr 16 09:37:33 2011 +0000

Parent:

2:8aa059e7d8b1

Child:

4:1e3a53f150aa

Commit message:

1.13 See ChangeLog.c

Changed in this revision

--- a/ChangeLog.c	Fri Apr 15 12:23:52 2011 +0000
+++ b/ChangeLog.c	Sat Apr 16 09:37:33 2011 +0000
@@ -64,5 +64,11 @@
 
     * Added VTG sentence (vectors speed and direction)
       See example3.cpp
-                                 
+
+1.13 - 16/04/2011
+
+    * Found that concat commas in NMEA sentences (indicating an empty field)
+      caused strtok() to return pointers in incorrect positions. 
+    * Found copying geodetic and vtg data structs to temp buffers actually
+      didn't work properly.                              
 */

--- a/GPS.cpp	Fri Apr 15 12:23:52 2011 +0000
+++ b/GPS.cpp	Sat Apr 16 09:37:33 2011 +0000
@@ -24,6 +24,10 @@
 
 GPS::GPS(PinName tx, PinName rx, const char *name) : Serial(tx, rx, name) 
 {
+    _nmeaOnUart0 = false;
+    
+    _lastByte = 0;
+    
     switch(_uidx) {
         case 1:   _base = LPC_UART1; break;
         case 2:   _base = LPC_UART2; break;
@@ -84,15 +88,15 @@
 GPS_Geodetic *
 GPS::geodetic(GPS_Geodetic *q)
 {
-    GPS_Geodetic a, b;
+    GPS_Geodetic a;
     
     if (q == NULL) q = new GPS_Geodetic;
     
     do {
         memcpy(&a, &thePlace, sizeof(GPS_Geodetic));
-        memcpy(&b, &thePlace, sizeof(GPS_Geodetic));
+        memcpy(q,  &thePlace, sizeof(GPS_Geodetic));
     }
-    while (memcmp(&a, &b, sizeof(GPS_Geodetic)) != 0);
+    while (memcmp(&a, q, sizeof(GPS_Geodetic)) != 0);
     
     return q;
 }
@@ -100,15 +104,15 @@
 GPS_VTG *
 GPS::vtg(GPS_VTG *q)
 {
-    GPS_VTG a, b;
+    GPS_VTG a;
     
     if (q == NULL) q = new GPS_VTG;
     
     do {
         memcpy(&a, &theVTG, sizeof(GPS_VTG));
-        memcpy(&b, &theVTG, sizeof(GPS_VTG));
+        memcpy(q,  &theVTG, sizeof(GPS_VTG));
     }
-    while (memcmp(&a, &b, sizeof(GPS_VTG)) != 0);
+    while (memcmp(&a, q, sizeof(GPS_VTG)) != 0);
     
     return q;
 }
@@ -156,15 +160,34 @@
     if (_base) {
         iir = (uint32_t)*((char *)_base + GPS_IIR); 
         while((int)(*((char *)_base + GPS_LSR) & 0x1)) {
-            c = (char)(*((char *)_base + GPS_RBR) & 0xFF); 
-            // debugging LPC_UART0->RBR = c;
-            buffer[active_buffer][rx_buffer_in++] = c;
-            rx_buffer_in &= (GPS_BUFFER_LEN - 1);
+            c = (char)(*((char *)_base + GPS_RBR) & 0xFF);             
+            
+            // strtok workaround. 
+            // Found that ,, together (which some NMEA sentences
+            // contain for a null/empty field) confuses strtok()
+            // function. Solution:- Push a "zero" into the string 
+            // for missing/empty fields.
+            if (c == ',' && _lastByte == ',') {
+                buffer[active_buffer][rx_buffer_in] = '0';
+                if (++rx_buffer_in >= GPS_BUFFER_LEN) rx_buffer_in = 0;
+            }
+            
+            // Debugging/dumping data. 
+            if (_nmeaOnUart0) LPC_UART0->RBR = c; 
+            
+            // Put the byte into the string.
+            buffer[active_buffer][rx_buffer_in] = c;
+            if (++rx_buffer_in >= GPS_BUFFER_LEN) rx_buffer_in = 0;
+            
+            // Save for next time an irq occurs. See strtok() above.
+            _lastByte = c;
+            
+            // If end of NMEA sentence flag for processing.
             if (c == '\n') {
                 active_buffer = active_buffer == 0 ? 1 : 0;
                 process_required = true;
                 rx_buffer_in = 0;                
-            }
+            }            
         }
     }
 }      

--- a/GPS.h	Fri Apr 15 12:23:52 2011 +0000
+++ b/GPS.h	Sat Apr 16 09:37:33 2011 +0000
@@ -696,6 +696,7 @@
     
     //! A callback object for the NMEA RMS message processed signal user API.
     FunctionPointer cb_vtg;
+    
     //! Set the baud rate the GPS module is using.
     /** 
      * Set the baud rate of the serial port
@@ -707,7 +708,7 @@
      */
     void baud(int baudrate) { Serial::baud(baudrate); }
     
-    //! Set the serial port format the GPS module is using. 
+   //! Set the serial port format the GPS module is using. 
    /**
     * Set the transmission format used by the Serial port
     *
@@ -720,6 +721,24 @@
     */
     void format(int bits, Parity parity, int stop_bits) { Serial::format(bits, (Serial::Parity)parity, stop_bits); }
     
+   //! Send incoming GPS bytes to Uart0
+   /**
+    * Send incoming GPS bytes to Uart0
+    *
+    * This can be useful for printing out the bytes from the GPS onto
+    * a the common debug port Uart0. Note, Uart0 should have been setup
+    * and initialised before switching this on. Also, realistically,
+    * you should ensure Uart0 has a higher baud rate than that being
+    * used by the GPS. Sending of bytes to Uart0 is "raw" and should
+    * only be used to initially gather data and should NOT be used as
+    * part of the application design. If you need to forward on the 
+    * data you should come up with a proper strategy.
+    *
+    * @ingroup API 
+    * @param b - True to send to Uart0, false otherwise
+    */
+    void NmeaOnUart0(bool b) { _nmeaOnUart0 = b; }
+        
 protected:
 
     //! Flag set true when a GPS PPS has been attached to a pin.
@@ -738,7 +757,13 @@
     GPS_Geodetic thePlace;
     
     //! A GPS_VTG object used to hold vector data.
-    GPS_VTG      theVTG;       
+    GPS_VTG      theVTG; 
+    
+    //! Used to record the previous byte received.
+    char _lastByte;
+    
+    //! Used for debugging.
+    bool _nmeaOnUart0;      
 };
 
 #endif

--- a/GPS_VTG.cpp	Fri Apr 15 12:23:52 2011 +0000
+++ b/GPS_VTG.cpp	Sat Apr 16 09:37:33 2011 +0000
@@ -21,6 +21,7 @@
 */
 
 #include "GPS_VTG.h"
+#include <math.h>
 
 GPS_VTG::GPS_VTG() 
 {
@@ -35,10 +36,11 @@
 {
     if (n == NULL) n = new GPS_VTG;
     
-    do {
-        memcpy(n, this, sizeof(GPS_VTG));
-    }
-    while (memcmp(n, this, sizeof(GPS_VTG)));
+    n->_velocity_knots = _velocity_knots;
+    n->_velocity_kph   = _velocity_kph;
+    n->_track_true     = _track_true;
+    n->_track_mag      = _track_mag;
+    
     return n;    
 }
 
@@ -64,9 +66,9 @@
         token_counter++;
     }
     
+    if (trk_t)     { _track_true     = atof(trk_t);     }
+    if (trk_m)     { _track_mag      = atof(trk_m);     }    
     if (vel_knots) { _velocity_knots = atof(vel_knots); }
-    if (vel_kph)   { _velocity_kph   = atof(vel_kph); }
-    if (trk_t)     { _track_true     = atof(trk_t); }
-    if (trk_m)     { _track_mag      = atof(trk_m); }    
+    if (vel_kph)   { _velocity_kph   = atof(vel_kph);   }    
 }
 

--- a/GPS_VTG.h	Fri Apr 15 12:23:52 2011 +0000
+++ b/GPS_VTG.h	Sat Apr 16 09:37:33 2011 +0000
@@ -24,6 +24,7 @@
 #define GPS_VTG_H
 
 #include "mbed.h"
+#include "iomacros.h"
 
 /** GPS_Time definition.
  */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/info.h	Sat Apr 16 09:37:33 2011 +0000
@@ -0,0 +1,13 @@
+/*
+
+Typical NMEA sentences from my GPS module.
+
+$GPGGA,075851.891,5611.5305,N,00302.0369,W,0,00,4.8,44.0,M,52.0,M,,0000*77
+$GPGSA,A,1,,,,,,,,,,,,,4.8,4.8,0.7*37
+$GPGSV,3,1,12,20,82,116,,01,79,246,,32,54,077,,17,48,254,*70
+$GPGSV,3,2,12,23,46,168,,24,40,128,,04,25,295,,11,24,143,*73
+$GPGSV,3,3,12,31,22,065,,13,15,190,,12,11,343,,25,00,019,*7D
+$GPRMC,075851.891,V,5611.5305,N,00302.0369,W,002.2,252.9,160411,,,N*68
+$GPVTG,252.9,T,,M,002.2,N,004.1,K,N*0B
+
+*/
\ No newline at end of file