Improved GPS management routine

openrtx/src/core/gps.c

@@ -27,7 +27,7 @@
 
 #define KNOTS2KMH 1.852f
 
-static char sentence[MINMEA_MAX_LENGTH + 1];
+static char sentence[2*MINMEA_MAX_LENGTH];
 static bool isRtcSyncronised  = false;
 static bool gpsEnabled        = false;
 static bool readNewSentence   = true;
@@ -52,14 +52,22 @@ void gps_taskFunc()
     // Acquire a new NMEA sentence from GPS
     if(readNewSentence)
     {
-        int status = gps_getNmeaSentence(sentence, MINMEA_MAX_LENGTH + 1);
+        int status = gps_getNmeaSentence(sentence, 2*MINMEA_MAX_LENGTH);
         if(status != 0) return;
         readNewSentence = false;
     }
 
+    // Waiting for a sentence...
     if(gps_nmeaSentenceReady() == false)
         return;
 
+    // Discard all non-GPS sentences
+    if((sentence[0] != '$') || (sentence[1] != 'G'))
+    {
+        readNewSentence = true;
+        return;
+    }
+
     // Parse the sentence. Work on a local state copy to minimize the time
     // spent with the state mutex locked
     gps_t gps_data;

openrtx/src/core/threads.c

@@ -139,26 +139,30 @@ void *dev_task(void *arg)
     if(state.gpsDetected) gps_init(9600);
     #endif
 
+    uint8_t tick_5ms = 0;
+
     while(state.shutdown == false)
     {
-        // Update radio state
-        state_update();
+        tick_5ms++;
 
         #if defined(GPS_PRESENT) && !defined(MD3x0_ENABLE_DBG)
         if(state.gpsDetected)
-        {
             gps_taskFunc();
-        }
         #endif
 
-        // Signal state update to UI thread
-        event_t dev_msg;
-        dev_msg.type = EVENT_STATUS;
-        dev_msg.payload = 0;
-        ui_pushEvent(dev_msg);
+        // Update radio state and push an event to the UI every 100ms
+        if((tick_5ms % 20) == 0)
+        {
+            state_update();
 
-        // 10Hz update rate
-        sleepFor(0u, 100u);
+            event_t dev_msg;
+            dev_msg.type = EVENT_STATUS;
+            dev_msg.payload = 0;
+            ui_pushEvent(dev_msg);
+        }
+
+        // Run this loop once every 5ms
+        sleepFor(0u, 5u);
     }
 
     #if defined(GPS_PRESENT)