Updated documentation and improved XCVR RSSI calculation

    Documented dboard sensors
    Documented DBSRX2
    Added description of direct conversion vs low IF for each dboard
    Added E1xx docs for adding refclock and pps connectors

    XCVR rssi calculation was in unscaled dB units
        Used chart in datasheet (pg 16) to rescale to dBm

1 files changed, 11 insertions, 2 deletions

diff --git a/host/lib/usrp/dboard/db_xcvr2450.cpp b/host/lib/usrp/dboard/db_xcvr2450.cpp
index 9d25b30a5..70b0bbabd 100644
--- a/host/lib/usrp/dboard/db_xcvr2450.cpp
+++ b/host/lib/usrp/dboard/db_xcvr2450.cpp
@@ -152,12 +152,21 @@ private:
      * \return the rssi in dB
      */
     double get_rssi(void){
+        //*FIXME* RSSI depends on LNA Gain Setting (datasheet pg 16 top middle chart)
+        double max_power;
+        switch(_max2829_regs.rx_lna_gain){
+        case 0:
+        case 1: max_power = 0;    break;
+        case 2: max_power = -15;   break;
+        case 3: max_power = -30.5; break;
+        }
+
         //constants for the rssi calculation
         static const double min_v = 0.5, max_v = 2.5;
         static const double rssi_dyn_range = 60;
         //calculate the rssi from the voltage
         double voltage = this->get_iface()->read_aux_adc(dboard_iface::UNIT_RX, dboard_iface::AUX_ADC_B);
-        return rssi_dyn_range*(voltage - min_v)/(max_v - min_v);
+        return max_power - rssi_dyn_range*(voltage - min_v)/(max_v - min_v);
     }
 };
 
@@ -621,7 +630,7 @@ void xcvr2450::rx_get(const wax::obj &key_, wax::obj &val){
         if (key.name == "lo_locked")
             val = sensor_value_t("LO", this->get_locked(), "locked", "unlocked");
         else if (key.name == "rssi")
-            val = sensor_value_t("RSSI", this->get_rssi(), "dB");
+            val = sensor_value_t("RSSI", this->get_rssi(), "dBm");
         else
             UHD_THROW_INVALID_CODE_PATH();
         return;