UHD: implemented gps_locked sensor. usrp2 mboard doesn't init VITA time if time not valid.

4 files changed, 44 insertions, 22 deletions

diff --git a/host/docs/sync.rst b/host/docs/sync.rst
index 9284d8e33..3cb13fbf3 100644
--- a/host/docs/sync.rst
+++ b/host/docs/sync.rst
@@ -102,22 +102,11 @@ and the user can also parse this string to determine GPS time:
     usrp->set_time_next_pps(uhd::time_spec_t(gps_time+1));
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Method 3 - query the gps_time sensor
+Method 3 - internal GPSDO
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-This is a variant of method 2 for USRPs with internal GPSDOs.
-The user can query the gps_time sensor to wait for the NMEA string.
-
-::
-
-    //wait for NMEA string from internal GPSDO
-    usrp->get_mboard_sensor("gps_time");
-    usrp->set_time_next_pps(uhd::time_spec_t(0.0));
-
-    -- OR --
-
-    //wait for the NMEA string and set GPS time
-    const time_t gps_time = usrp->get_mboard_sensor("gps_time").to_int();
-    usrp->set_time_next_pps(uhd::time_spec_t(gps_time+1));
+USRPs with internal GPSDOs properly configured will automatically
+configure themselves to set the VITA time to current UTC time. See the
+GPSDO application note for more details.
 
 ------------------------------------------------------------------------
 Synchronizing channel phase
diff --git a/host/docs/usrp2.rst b/host/docs/usrp2.rst
index 88b217f1b..fa811d0f6 100644
--- a/host/docs/usrp2.rst
+++ b/host/docs/usrp2.rst
@@ -349,9 +349,8 @@ Test the PPS input with the following app:
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Internal GPSDO
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-USRP-N2XX models can have an optional internal GPSDO.
-To use the GPSDO with UHD, you must burn an EEPROM setting
-so that UHD knows that the internal GPSDO was installed.
+Please see the GPSDO application note for information on configuring and
+using the internal GPSDO.
 
 **Installation instructions:**
 
diff --git a/host/lib/usrp/gps_ctrl.cpp b/host/lib/usrp/gps_ctrl.cpp
index 55f46ffb3..2c2843877 100644
--- a/host/lib/usrp/gps_ctrl.cpp
+++ b/host/lib/usrp/gps_ctrl.cpp
@@ -184,6 +184,24 @@ public:
     return (gps_type != GPS_TYPE_NONE);
   }
 
+  bool locked(void) {
+      std::string reply = get_nmea("GPGGA");
+      if(reply.size() <= 1) return false;
+
+      boost::tokenizer<boost::escaped_list_separator<char> > tok(reply);
+      std::vector<std::string> toked;
+
+      tok.assign(reply);
+      toked.assign(tok.begin(), tok.end());
+
+      if(toked.size() != 15) {
+        UHD_MSG(error) << "gps_locked: invalid GPGGA response";
+        return false;
+      }
+
+      return (toked[6] != "0"); //sorry, 2d fixes don't count =D
+  }
+
   //return a list of supported sensors
   std::vector<std::string> get_sensors(void) {
     std::vector<std::string> ret;
@@ -191,6 +209,7 @@ public:
     ret.push_back("gps_gprmc");
     ret.push_back("gps_gpgsa");
     ret.push_back("gps_time");
+    ret.push_back("gps_locked");
     return ret;
   }
 
@@ -206,6 +225,9 @@ public:
     else if(key == "gps_time") {
         return sensor_value_t("GPS epoch time", int(get_epoch_time()), "seconds");
     }
+    else if(key == "gps_locked") {
+        return sensor_value_t("GPS lock status", locked(), "locked", "unlocked");
+    }
     else {
         UHD_THROW_PROP_GET_ERROR();
     }
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index 3733915a2..12fff96d0 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -149,7 +149,13 @@ usrp2_mboard_impl::usrp2_mboard_impl(
         (_mimo_clocking_mode_is_master?"master":"slave") << std::endl;
 
     //init the clock config
-    _clock_config = clock_config_t::internal();
+    if(_iface->mb_eeprom["gpsdo"] == "internal" or
+       _iface->mb_eeprom["gpsdo"] == "external") {
+        _clock_config = clock_config_t::external();
+    }
+    else {
+        _clock_config = clock_config_t::internal();
+    }
     update_clock_config();
 
     //init the codec before the dboard
@@ -176,9 +182,15 @@ usrp2_mboard_impl::usrp2_mboard_impl(
     //------------------------------------------------------------------
 
     //initialize VITA time to GPS time
-    if(_gps_ctrl.get() and _gps_ctrl->gps_detected()) {
-        UHD_MSG(status) << "Setting device time to GPS time...\n";
-        set_time_spec(time_spec_t(double(_gps_ctrl->get_sensor("gps_time").to_int()+1)), false);
+    if( _gps_ctrl.get()
+    and _gps_ctrl->gps_detected()) {
+        if(_gps_ctrl->get_sensor("gps_locked").to_bool()) {
+            UHD_MSG(status) << "Setting device time to GPS time...\n";
+            set_time_spec(time_spec_t(double(_gps_ctrl->get_sensor("gps_time").to_int()+1)), false);
+        }
+        else {
+            UHD_MSG(status) << "GPS not locked to satellites. Not initializing VITA time.";
+        }
     }
 }