Added GPS watchdog.

m20/Core/Inc/config.h

@@ -18,6 +18,8 @@ const static float QRG_FSK4[] = {435100000}; // Transmitted frequencies array, s
 
 #define GPS_TYPE 1              // Type of GPS module: 1 - u-blox | 2 - XM1110
 
+#define GPS_WATCHDOG 3            // number of frames without gps fix to trigger restart
+
 #define PA_FSK4 10              // RF power setting for horus transmission values 0-63
 #define RF_BOOST_ACTIVE 1       // RF booster enabled for transmissions about 15dB gain, but more power consumed - normally should be ON(1).
 

m20/Core/Src/main.c

@@ -59,6 +59,11 @@ const static uint8_t GPS_airborne[44] = {
 XMDATA GpsData;
 #endif
 
+#ifdef GPS_WATCHDOG
+uint8_t GpsWatchdogCounter = 0;
+bool PreviousFix = false;
+#endif
+
 uint8_t lps_init;
 
 HorusBinaryPacket HorusPacket;
@@ -112,6 +117,30 @@ PUTCHAR_PROTOTYPE {
 /* Private user code ---------------------------------------------------------*/
 /* USER CODE BEGIN 0 */
 void main_loop(void) {
+#ifdef GPS_WATCHDOG
+#if GPS_TYPE == 1
+  if (NmeaData.Fix > 1 && NmeaData.Sats > 0)
+    PreviousFix = true;
+  if (PreviousFix && (NmeaData.Fix <= 1 || NmeaData.Sats == 0)) {
+    GpsWatchdogCounter++;
+  } else {
+    GpsWatchdogCounter = 0;
+  }
+#elif GPS_TYPE == 2
+  if (GpsData.Fix > 0 && GpsData.Sats > 0)
+    PreviousFix = true;
+  if (PreviousFix && (GpsData.Fix == 0 || GpsData.Sats == 0)) {
+    GpsWatchdogCounter++;
+  } else {
+    GpsWatchdogCounter = 0;
+  }
+#endif
+  if (GpsWatchdogCounter >= GPS_WATCHDOG) {
+    LL_GPIO_ResetOutputPin(GPS_ON_GPIO_Port, GPS_ON_Pin); // disable GPS
+    while (1) {
+    } // trigger a restart with IWDG
+  }
+#endif
   // LED
 #if LED_MODE == 1
   LL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);