3 files changed, 12 insertions, 1 deletions
diff --git a/host/lib/usrp/b200/b200_impl.cpp b/host/lib/usrp/b200/b200_impl.cpp
index 1523f1858..8ea50296f 100644
--- a/host/lib/usrp/b200/b200_impl.cpp
+++ b/host/lib/usrp/b200/b200_impl.cpp
@@ -684,7 +684,9 @@ void b200_impl::setup_radio(const size_t dspno)
         const fs_path rf_fe_path = mb_path / "dboards" / "A" / (x+"_frontends") / (dspno? "B" : "A");
 
         _tree->create<std::string>(rf_fe_path / "name").set("FE-"+key);
-        _tree->create<int>(rf_fe_path / "sensors"); //empty TODO
+        _tree->create<int>(rf_fe_path / "sensors");
+        _tree->create<sensor_value_t>(rf_fe_path / "sensors" / "lo_locked")
+            .publish(boost::bind(&b200_impl::get_fe_pll_locked, this, x == "tx"));
         BOOST_FOREACH(const std::string &name, ad9361_ctrl::get_gain_names(key))
         {
             _tree->create<meta_range_t>(rf_fe_path / "gains" / name / "range")
@@ -1059,3 +1061,10 @@ sensor_value_t b200_impl::get_ref_locked(void)
     const bool lock = (_local_ctrl->peek32(RB32_CORE_MISC) & 0x1) == 0x1;
     return sensor_value_t("Ref", lock, "locked", "unlocked");
 }
+
+sensor_value_t b200_impl::get_fe_pll_locked(const bool is_tx)
+{
+    const boost::uint32_t st = _local_ctrl->peek32(RB32_CORE_PLL);
+    const bool locked = is_tx ? st & 0x1 : st & 0x2;
+    return sensor_value_t("LO", locked, "locked", "unlocked");
+}
diff --git a/host/lib/usrp/b200/b200_impl.hpp b/host/lib/usrp/b200/b200_impl.hpp
index 71592f60b..64d7aa7d0 100644
--- a/host/lib/usrp/b200/b200_impl.hpp
+++ b/host/lib/usrp/b200/b200_impl.hpp
@@ -149,6 +149,7 @@ private:
     void update_bandsel(const std::string& which, double freq);
     void update_antenna_sel(const size_t which, const std::string &ant);
     uhd::sensor_value_t get_ref_locked(void);
+    uhd::sensor_value_t get_fe_pll_locked(const bool is_tx);
 
     //perifs in the radio core
     struct radio_perifs_t
diff --git a/host/lib/usrp/b200/b200_regs.hpp b/host/lib/usrp/b200/b200_regs.hpp
index dc8a6b0dc..900651f94 100644
--- a/host/lib/usrp/b200/b200_regs.hpp
+++ b/host/lib/usrp/b200/b200_regs.hpp
@@ -32,6 +32,7 @@ localparam SR_CORE_PPS_SEL   = 48;
 localparam RB32_CORE_SPI     = 8;
 localparam RB32_CORE_MISC    = 16;
 localparam RB32_CORE_STATUS  = 20;
+localparam RB32_CORE_PLL     = 24;
 
 localparam SR_SPI       = 8;
 localparam SR_ATR       = 12;