AP_RCProtocol: add extended RC link stats OSD fields

Adds RSSI dBm, SNR, LQ, Tx power and active antenna OSD fields

libraries/AP_RCProtocol/AP_RCProtocol_CRSF.cpp

@@ -160,7 +160,7 @@ static const char* get_frame_type(uint8_t byte, uint8_t subtype = 0)
 
 const uint16_t AP_RCProtocol_CRSF::RF_MODE_RATES[RFMode::RF_MODE_MAX_MODES] = {
     4, 50, 150, 250,    // CRSF
-    4, 25, 50, 100, 150, 200, 250, 500  // ELRS
+    4, 25, 50, 100, 100, 150, 200, 250, 333, 500, 250, 500, 500, 1000, 50  // ELRS
 };
 
 AP_RCProtocol_CRSF* AP_RCProtocol_CRSF::_singleton;
@@ -204,7 +204,7 @@ const char* AP_RCProtocol_CRSF::get_protocol_string(ProtocolType protocol) const
 // return the link rate as defined by the LinkStatistics
 uint16_t AP_RCProtocol_CRSF::get_link_rate(ProtocolType protocol) const {
     if (protocol == ProtocolType::PROTOCOL_ELRS) {
-        return RF_MODE_RATES[_link_status.rf_mode + RFMode::ELRS_RF_MODE_4HZ];
+        return RF_MODE_RATES[_link_status.rf_mode + RFMode::CRSF_RF_MAX_MODES];
     } else if (protocol == ProtocolType::PROTOCOL_TRACER) {
         return 250;
     } else {
@@ -573,6 +573,11 @@ bool AP_RCProtocol_CRSF::process_telemetry(bool check_constraint)
     return true;
 }
 
+#if AP_OSD_LINK_STATS_EXTENSIONS_ENABLED
+    // Define the static tx powers array
+    constexpr uint16_t AP_RCProtocol_CRSF::tx_powers[];
+#endif
+
 // process link statistics to get RSSI
 void AP_RCProtocol_CRSF::process_link_stats_frame(const void* data)
 {
@@ -585,6 +590,7 @@ void AP_RCProtocol_CRSF::process_link_stats_frame(const void* data)
         rssi_dbm = link->uplink_rssi_ant2;
     }
     _link_status.link_quality = link->uplink_status;
+
     if (_use_lq_for_rssi) {
         _link_status.rssi = derive_scaled_lq_value(link->uplink_status);
     } else{
@@ -599,7 +605,28 @@ void AP_RCProtocol_CRSF::process_link_stats_frame(const void* data)
         }
     }
 
-    _link_status.rf_mode = MIN(link->rf_mode, 7U);
+    // Define the max number of RFModes based on ELRS modes, which is larger than Crossfire
+    const uint8_t max_modes = (RFMode::RF_MODE_MAX_MODES - RFMode::CRSF_RF_MAX_MODES) - 1U; // Subtract 1 due to zero-indexing
+    _link_status.rf_mode = MIN(link->rf_mode, max_modes); // Cap to avoid memory spills in the conversion tables
+
+#if AP_OSD_LINK_STATS_EXTENSIONS_ENABLED
+    // Populate the extra data items
+    if (link->uplink_status > 0) {
+        _link_status.rssi_dbm = rssi_dbm;
+        _link_status.tx_power = -1;
+        if (link->uplink_tx_power < ARRAY_SIZE(AP_RCProtocol_CRSF::tx_powers)) {
+            _link_status.tx_power = AP_RCProtocol_CRSF::tx_powers[link->uplink_tx_power];
+        }
+        _link_status.snr = link->uplink_snr;
+        _link_status.active_antenna = link->active_antenna;
+    } else {
+        // This means LQ is zero, so set all values to "no signal" state
+        _link_status.rssi_dbm = -1;
+        _link_status.tx_power = -1;
+        _link_status.snr = INT8_MIN;
+        _link_status.active_antenna = -1;
+    }
+#endif
 }
 
 // process link statistics to get RX RSSI

libraries/AP_RCProtocol/AP_RCProtocol_CRSF.h

@@ -27,6 +27,7 @@
 #include <AP_Math/AP_Math.h>
 #include <RC_Channel/RC_Channel.h>
 #include "SoftSerial.h"
+#include <AP_OSD/AP_OSD_config.h>
 
 #define CRSF_MAX_CHANNELS   24U      // Maximum number of channels from crsf datastream
 #define CRSF_FRAMELEN_MAX   64U      // maximum possible framelength
@@ -258,29 +259,51 @@ public:
         PROTOCOL_ELRS
     };
 
+    // Source for ELRS RF modes: https://www.expresslrs.org/info/signal-health/#rf-mode-indexes-rfmd
     enum RFMode {
         CRSF_RF_MODE_4HZ = 0,
         CRSF_RF_MODE_50HZ,
         CRSF_RF_MODE_150HZ,
         CRSF_RF_MODE_250HZ,
-        ELRS_RF_MODE_4HZ,
+        CRSF_RF_MAX_MODES = 4,
+        ELRS_RF_MODE_4HZ = 4,
         ELRS_RF_MODE_25HZ,
         ELRS_RF_MODE_50HZ,
         ELRS_RF_MODE_100HZ,
+        ELRS_RF_MODE_100HZ_FULL,
         ELRS_RF_MODE_150HZ,
         ELRS_RF_MODE_200HZ,
         ELRS_RF_MODE_250HZ,
+        ELRS_RF_MODE_333HZ_FULL,        
         ELRS_RF_MODE_500HZ,
+        ELRS_RF_MODE_D250HZ,
+        ELRS_RF_MODE_D500HZ,
+        ELRS_RF_MODE_F500HZ,
+        ELRS_RF_MODE_F1000HZ,
+        ELRS_RF_MODE_D50HZ,
         RF_MODE_MAX_MODES,
         RF_MODE_UNKNOWN,
     };
 
+#if AP_OSD_LINK_STATS_EXTENSIONS_ENABLED
+    // These power levels are valid for both Crossfire and ELRS systems
+    static constexpr uint16_t tx_powers[] = { 0, 10, 25, 100, 500, 1000, 2000, 250, 50 };    
+#endif
+
     struct LinkStatus {
         int16_t rssi = -1;
         int16_t link_quality = -1;
         uint8_t rf_mode;
+#if AP_OSD_LINK_STATS_EXTENSIONS_ENABLED
+        // Add the extra data fields to be used by the OSD panels
+        int16_t tx_power = -1;
+        int8_t rssi_dbm = -1;
+        int8_t snr = INT8_MIN;
+        int8_t active_antenna = -1;
+#endif
     };
 
+
     // this will be used by AP_CRSF_Telem to access link status data
     // from within AP_RCProtocol_CRSF thread so no need for cross-thread synch
     const volatile LinkStatus& get_link_status() const {