Diff: GPS.cpp

Revision:

3:28a1b60b0f37

Parent:

2:8aa059e7d8b1

Child:

5:7f130f85d5a4

--- 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;                
-            }
+            }            
         }
     }
 }