Rover: 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

APMrover2/APMrover2.cpp

@@ -94,8 +94,8 @@ void Rover::setup()
     AP_Notify::flags.pre_arm_check = true;
     AP_Notify::flags.pre_arm_gps_check = true;
     AP_Notify::flags.failsafe_battery = false;
-
-    rssi_analog_source = hal.analogin->channel(ANALOG_INPUT_NONE);
+    
+    rssi.init();
 
     init_ardupilot();
 

APMrover2/Parameters.cpp

@@ -37,13 +37,6 @@ const AP_Param::Info Rover::var_info[] PROGMEM = {
     // @User: Advanced
 	GSCALAR(initial_mode,        "INITIAL_MODE",     MANUAL),
 
-    // @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, 2:APM2 A2, 13:APM2 A13, 103:Pixhawk SBUS
-    // @User: Standard
-    GSCALAR(rssi_pin,            "RSSI_PIN",         -1),
-
     // @Param: SYSID_THIS_MAV
     // @DisplayName: MAVLink system ID of this vehicle
     // @Description: Allows setting an individual MAVLink system id for this vehicle to distinguish it from others on the same network
@@ -540,6 +533,10 @@ const AP_Param::Info Rover::var_info[] PROGMEM = {
     // @Group: MIS_
     // @Path: ../libraries/AP_Mission/AP_Mission.cpp
     GOBJECT(mission, "MIS_",       AP_Mission),
+    
+    // @Group: RSSI_
+    // @Path: ../libraries/AP_RSSI/AP_RSSI.cpp
+    GOBJECT(rssi, "RSSI_",  AP_RSSI),        
 
 	AP_VAREND
 };

APMrover2/Parameters.h

@@ -40,7 +40,7 @@ public:
         k_param_rc_14,
 
         // IO pins
-        k_param_rssi_pin = 20,
+        k_param_rssi_pin = 20,      // unused, replaced by rssi_ library parameters
         k_param_battery_volt_pin,
         k_param_battery_curr_pin,
 
@@ -55,7 +55,9 @@ public:
         k_param_serial1_baud,   // deprecated, can be deleted
         k_param_serial2_baud,   // deprecated, can be deleted
 
-
+        // 97: RSSI
+        k_param_rssi = 97,
+                
         // 110: Telemetry control
         //
         k_param_gcs0 = 110, // stream rates for uartA
@@ -203,9 +205,6 @@ public:
     AP_Int8	    reset_switch_chan;
     AP_Int8     initial_mode;
 
-    // IO pins
-    AP_Int8     rssi_pin;
-
     // braking
     AP_Int8     braking_percent;
     AP_Float    braking_speederr;

APMrover2/Rover.h

@@ -84,6 +84,7 @@
 #include <AP_Notify/AP_Notify.h>      // Notify library
 #include <AP_BattMonitor/AP_BattMonitor.h> // Battery monitor library
 #include <AP_OpticalFlow/AP_OpticalFlow.h>     // Optical Flow library
+#include <AP_RSSI/AP_RSSI.h>                   // RSSI Library
 
 // Configuration
 #include "config.h"
@@ -168,6 +169,9 @@ private:
     AP_Mission mission;
 
     OpticalFlow optflow;
+    
+    // RSSI 
+    AP_RSSI rssi;          
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
     SITL sitl;
@@ -178,10 +182,6 @@ private:
     const uint8_t num_gcs;
     GCS_MAVLINK gcs[MAVLINK_COMM_NUM_BUFFERS];
 
-    // a pin for reading the receiver RSSI voltage. The scaling by 0.25 
-    // is to take the 0 to 1024 range down to an 8 bit range for MAVLink
-    AP_HAL::AnalogSource *rssi_analog_source;
-
     // relay support
     AP_Relay relay;
 

APMrover2/make.inc

@@ -51,5 +51,6 @@ LIBRARIES += AP_HAL_Empty
 LIBRARIES += AP_Notify
 LIBRARIES += AP_BattMonitor
 LIBRARIES += AP_OpticalFlow
+LIBRARIES += AP_RSSI
 LIBRARIES += AP_Declination
 

APMrover2/sensors.cpp

@@ -25,9 +25,7 @@ void Rover::read_battery(void)
 // RC_CHANNELS_SCALED message
 void Rover::read_receiver_rssi(void)
 {
-    rssi_analog_source->set_pin(g.rssi_pin);
-    float ret = rssi_analog_source->voltage_average() * 50;
-    receiver_rssi = constrain_int16(ret, 0, 255);
+    receiver_rssi = rssi.read_receiver_rssi_uint8();
 }
 
 // read the sonars