fix 124 - we now fallback to nema if we can't talk ublox protocol to

the GPS.  Though we are super power inefficient about it so TODO/FIXME
someday to decrease our power draw.

docs/software/nrf52-TODO.md

@@ -8,7 +8,6 @@ Minimum items needed to make sure hardware is good.
 - use "variants" to get all gpio bindings
 - plug in correct variants for the real board
 - Use the PMU driver on real hardware
-- add a NEMA based GPS driver to test GPS
 - Use new radio driver on real hardware
 - Use UC1701 LCD driver on real hardware. Still need to create at startup and probe on SPI
 - test the LEDs
@@ -101,6 +100,7 @@ Nice ideas worth considering someday...
 - DONE neg 7 error code from receive
 - DONE remove unused sx1262 lib from github
 - at boot we are starting our message IDs at 1, rather we should start them at a random number. also, seed random based on timer. this could be the cause of our first message not seen bug.
+- add a NEMA based GPS driver to test GPS
 
 ```
 

src/gps/GPS.cpp

@@ -61,7 +61,7 @@ void perhapsSetRTC(struct tm &t)
     tv.tv_sec = res;
     tv.tv_usec = 0; // time.centisecond() * (10 / 1000);
 
-    DEBUG_MSG("Got time from GPS month=%d, year=%d, unixtime=%ld\n", t.tm_mon, t.tm_year, tv.tv_sec);
+    // DEBUG_MSG("Got time from GPS month=%d, year=%d, unixtime=%ld\n", t.tm_mon, t.tm_year, tv.tv_sec);
     if (t.tm_year < 0 || t.tm_year >= 300)
         DEBUG_MSG("Ignoring invalid GPS time\n");
     else

src/gps/NEMAGPS.cpp

@@ -12,45 +12,54 @@ static int32_t toDegInt(RawDegrees d)
 
 void NEMAGPS::loop()
 {
+
     while (_serial_gps.available() > 0) {
         int c = _serial_gps.read();
-        Serial.write(c);
+        // Serial.write(c);
         reader.encode(c);
     }
 
-    auto ti = reader.time;
-    auto d = reader.date;
-    if (ti.isUpdated() && ti.isValid() && d.isValid()) {
-        /* Convert to unix time
-The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970
-(midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).
-*/
-        struct tm t;
-        t.tm_sec = ti.second();
-        t.tm_min = ti.minute();
-        t.tm_hour = ti.hour();
-        t.tm_mday = d.day();
-        t.tm_mon = d.month() - 1;
-        t.tm_year = d.year() - 1900;
-        t.tm_isdst = false;
-        perhapsSetRTC(t);
-    }
+    uint32_t now = millis();
+    if ((now - lastUpdateMsec) > 20 * 1000) { // Ugly hack for now - limit update checks to once every 20 secs (but still consume
+                                              // serial chars at whatever rate)
+        lastUpdateMsec = now;
 
-    if (reader.altitude.isUpdated() || reader.location.isUpdated()) { // probably get updated at the same time
-        if (reader.altitude.isValid())
-            altitude = reader.altitude.meters();
+        auto ti = reader.time;
+        auto d = reader.date;
+        if (ti.isUpdated() && ti.isValid() && d.isValid()) {
+            /* Convert to unix time
+    The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970
+    (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).
+    */
+            struct tm t;
+            t.tm_sec = ti.second();
+            t.tm_min = ti.minute();
+            t.tm_hour = ti.hour();
+            t.tm_mday = d.day();
+            t.tm_mon = d.month() - 1;
+            t.tm_year = d.year() - 1900;
+            t.tm_isdst = false;
+            perhapsSetRTC(t);
 
-        auto loc = reader.location;
-        if (loc.isValid()) {
-            latitude = toDegInt(loc.rawLat());
-            longitude = toDegInt(loc.rawLng());
+            isConnected = true; // we seem to have a real GPS (but not necessarily a lock)
         }
 
-        // expect gps pos lat=37.520825, lon=-122.309162, alt=158
-        DEBUG_MSG("new NEMA GPS pos lat=%f, lon=%f, alt=%d\n", latitude * 1e-7, longitude * 1e-7, altitude);
+        if (reader.location.isUpdated()) {
+            if (reader.altitude.isValid())
+                altitude = reader.altitude.meters();
 
-        hasValidLocation = (latitude != 0) || (longitude != 0); // bogus lat lon is reported as 0,0
-        if (hasValidLocation)
-            notifyObservers(NULL);
+            if (reader.location.isValid()) {
+                auto loc = reader.location.value();
+                latitude = toDegInt(loc.lat);
+                longitude = toDegInt(loc.lng);
+            }
+
+            // expect gps pos lat=37.520825, lon=-122.309162, alt=158
+            DEBUG_MSG("new NEMA GPS pos lat=%f, lon=%f, alt=%d\n", latitude * 1e-7, longitude * 1e-7, altitude);
+
+            hasValidLocation = (latitude != 0) || (longitude != 0); // bogus lat lon is reported as 0,0
+            if (hasValidLocation)
+                notifyObservers(NULL);
+        }
     }
 }

src/gps/NEMAGPS.h

@@ -14,6 +14,8 @@ class NEMAGPS : public GPS
 {
     TinyGPSPlus reader;
     
+    uint32_t lastUpdateMsec = 0;
+
   public:
     virtual void loop();
 };

src/gps/UBloxGPS.cpp

@@ -28,7 +28,7 @@ bool UBloxGPS::setup()
     if (isConnected) {
         DEBUG_MSG("Connected to UBLOX GPS successfully\n");
 
-        bool factoryReset = true;
+        bool factoryReset = false;
         bool ok;
         if (factoryReset) {
             // It is useful to force back into factory defaults (9600baud, NEMA to test the behavior of boards that don't have