Introduce setDIOMapping on the PhysicalLayer class which, by default, returns "not implemented"

src/TypeDef.h

@@ -203,6 +203,16 @@
 */
 #define RADIOLIB_ERR_LORA_HEADER_DAMAGED                       (-24)
 
+/*!
+  \brief The requested functionality is not supported for this device
+*/
+#define RADIOLIB_ERR_UNSUPPORTED                               (-25)
+
+/*!
+  \brief The specified DIO pin does not exist on this device
+*/
+#define RADIOLIB_ERR_INVALID_DIO_PIN                           (-26)
+
 // RF69-specific status codes
 
 /*!

src/protocols/PhysicalLayer/PhysicalLayer.cpp

@@ -246,3 +246,7 @@ void PhysicalLayer::updateDirectBuffer(uint8_t bit) {
     }
   }
 }
+
+int16_t PhysicalLayer::setDIOMapping(RADIOLIB_PIN_TYPE pin, uint8_t value) {
+  return(RADIOLIB_ERR_UNSUPPORTED);  
+}

src/protocols/PhysicalLayer/PhysicalLayer.h

@@ -300,6 +300,17 @@ class PhysicalLayer {
     */
     uint8_t read();
 
+    /*!
+      \brief Configure DIO pin mapping to get a given signal on a DIO pin (if available).
+
+      \param pin Pin number onto which a signal is to be placed.
+
+      \param value The value that indicates which function to place on that pin. See chip datasheet for details.
+
+      \returns \ref status_codes
+    */
+    virtual int16_t setDIOMapping(RADIOLIB_PIN_TYPE pin, uint8_t value);
+
   protected:
     void updateDirectBuffer(uint8_t bit);