Plane: Moving to RSSI library for reading various kinds of RSSI, with the possibility of adding more.

* Retains ability to read from Analog Pin
* Adds ability to read RSSI from PWM channel value as is done in OpenLRSng, EazyUHF, and various other LRS.
* Handles any type of RSSI that provides RSSI values inverted - i.e. when the low value is the best signal and the high value is the worst signal.
* Has different key names from all existing RSSI parameters to provide for a clean break and easier distinguishing.
* Existing parameters are marked as obsolete

ArduPlane/ArduPlane.cpp

@@ -88,7 +88,7 @@ void Plane::setup()
 
     notify.init(false);
 
-    rssi_analog_source = hal.analogin->channel(ANALOG_INPUT_NONE);
+    rssi.init();
 
     init_ardupilot();
 

ArduPlane/Parameters.cpp

@@ -912,21 +912,6 @@ const AP_Param::Info Plane::var_info[] PROGMEM = {
     GSCALAR(override_channel,      "OVERRIDE_CHAN",  0),
 #endif
 
-    // @Param: RSSI_PIN
-    // @DisplayName: Receiver RSSI sensing pin
-    // @Description: This selects an analog pin for the receiver RSSI voltage. It assumes the voltage is 5V for max rssi, 0V for minimum
-    // @Values: -1:Disabled, 0:APM2 A0, 1:APM2 A1, 13:APM2 A13, 103:Pixhawk SBUS
-    // @User: Standard
-    GSCALAR(rssi_pin,            "RSSI_PIN",         -1),
-
-    // @Param: RSSI_RANGE
-    // @DisplayName: Receiver RSSI voltage range
-    // @Description: Receiver RSSI voltage range
-    // @Units: Volt
-    // @Values: 3.3:3.3V, 5.0:5V
-    // @User: Standard
-    GSCALAR(rssi_range,          "RSSI_RANGE",         5.0),
-
     // @Param: INVERTEDFLT_CH
     // @DisplayName: Inverted flight channel
     // @Description: A RC input channel number to enable inverted flight. If this is non-zero then the APM will monitor the corresponding RC input channel and will enable inverted flight when the channel goes above 1750.
@@ -1204,6 +1189,10 @@ const AP_Param::Info Plane::var_info[] PROGMEM = {
     // @Path: ../libraries/AP_NavEKF/AP_NavEKF.cpp
     GOBJECTN(EKF, NavEKF, "EKF_", NavEKF),
 #endif
+    
+    // @Group: RSSI_
+    // @Path: ../libraries/AP_RSSI/AP_RSSI.cpp
+    GOBJECT(rssi, "RSSI_",  AP_RSSI),
 
     AP_VAREND
 };

ArduPlane/Parameters.h

@@ -101,7 +101,7 @@ public:
         k_param_sonar_old, // unused
         k_param_log_bitmask,
         k_param_BoardConfig,
-        k_param_rssi_range,
+        k_param_rssi_range,     // unused, replaced by rssi_ library parameters
         k_param_flapin_channel,
         k_param_flaperon_output,
         k_param_gps,
@@ -141,6 +141,9 @@ public:
         k_param_gcs_pid_mask,
         k_param_crash_detection_enable,
 
+        // 97: RSSI
+        k_param_rssi = 97,
+        
         // 100: Arming parameters
         k_param_arming = 100,
 
@@ -222,9 +225,9 @@ public:
         // Battery monitoring parameters
         //
         k_param_battery = 166,
-        k_param_rssi_pin,
-        k_param_battery_volt_pin,   // unused
-        k_param_battery_curr_pin,   // unused - 169
+        k_param_rssi_pin,               // unused, replaced by rssi_ library parameters - 167
+        k_param_battery_volt_pin,       // unused - 168
+        k_param_battery_curr_pin,       // unused - 169
 
         //
         // 170: Radio settings
@@ -460,9 +463,7 @@ public:
     AP_Int8 flap_2_percent;
     AP_Int8 flap_2_speed;
     AP_Int8 land_flap_percent;
-    AP_Int8 takeoff_flap_percent;
-    AP_Int8 rssi_pin;
-    AP_Float rssi_range;             // allows to set max voltage for rssi pin such as 5.0, 3.3 etc.     
+    AP_Int8 takeoff_flap_percent;  
     AP_Int8 inverted_flight_ch;             // 0=disabled, 1-8 is channel for inverted flight trigger
     AP_Int8 stick_mixing;
     AP_Float takeoff_throttle_min_speed;

ArduPlane/Plane.h

@@ -91,6 +91,7 @@
 #include <AP_Rally/AP_Rally.h>
 
 #include <AP_OpticalFlow/AP_OpticalFlow.h>     // Optical Flow library
+#include <AP_RSSI/AP_RSSI.h>                   // RSSI Library
 
 // Configuration
 #include "config.h"
@@ -248,10 +249,6 @@ private:
     // selected navigation controller
     AP_SpdHgtControl *SpdHgt_Controller = &TECS_controller;
 
-    // Analog Inputs
-    // a pin for reading the receiver RSSI voltage. 
-    AP_HAL::AnalogSource *rssi_analog_source;
-
     // Relay
     AP_Relay relay;
 
@@ -270,6 +267,9 @@ private:
 
     // Rally Ponints
     AP_Rally rally {ahrs};
+    
+    // RSSI 
+    AP_RSSI rssi;      
 
     // remember if USB is connected, so we can adjust baud rate
     bool usb_connected;

ArduPlane/make.inc

@@ -47,6 +47,7 @@ LIBRARIES += AP_Frsky_Telem
 LIBRARIES += AP_ServoRelayEvents
 LIBRARIES += AP_Rally
 LIBRARIES += AP_OpticalFlow
+LIBRARIES += AP_RSSI
 LIBRARIES += AP_HAL_AVR
 LIBRARIES += AP_HAL_SITL
 LIBRARIES += AP_HAL_PX4

ArduPlane/sensors.cpp

@@ -1,6 +1,7 @@
 // -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 #include "Plane.h"
+#include <AP_RSSI/AP_RSSI.h>
 
 void Plane::init_barometer(void)
 {
@@ -82,18 +83,10 @@ void Plane::read_battery(void)
     }
 }
 
-
 // read the receiver RSSI as an 8 bit number for MAVLink
 // RC_CHANNELS_SCALED message
 void Plane::read_receiver_rssi(void)
 {
-    // avoid divide by zero
-    if (g.rssi_range <= 0) {
-        receiver_rssi = 0;
-    }else{
-        rssi_analog_source->set_pin(g.rssi_pin);
-        float ret = rssi_analog_source->voltage_average() * 255 / g.rssi_range;
-        receiver_rssi = constrain_int16(ret, 0, 255);
-    }
+    receiver_rssi = rssi.read_receiver_rssi_uint8();
 }