[SX128x] Implemented RF switch control

examples/SX128x/SX128x_Transmit/SX128x_Transmit.ino

@@ -47,6 +47,16 @@ void setup() {
     Serial.println(state);
     while (true);
   }
+
+  // some modules have an external RF switch
+  // controlled via two pins (RX enable, TX enable)
+  // to enable automatic control of the switch,
+  // call the following method
+  // RX enable:   4
+  // TX enable:   5
+  /*
+    lora.setRfSwitchPins(4, 5);
+  */
 }
 
 void loop() {

src/modules/SX128x/SX128x.cpp

@@ -477,6 +477,9 @@ int16_t SX128x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
   state = clearIrqStatus();
   RADIOLIB_ASSERT(state);
 
+  // set RF switch (if present)
+  _mod->setRfSwitchState(true);
+
   // start transmission
   state = setTx(SX128X_TX_TIMEOUT_NONE);
   RADIOLIB_ASSERT(state);
@@ -513,6 +516,9 @@ int16_t SX128x::startReceive(uint16_t timeout) {
     RADIOLIB_ASSERT(state);
   }
 
+  // set RF switch (if present)
+  _mod->setRfSwitchState(false);
+
   // set mode to receive
   state = setRx(timeout);
 
@@ -1090,6 +1096,10 @@ int16_t SX128x::setEncoding(uint8_t encoding) {
   return(setWhitening(encoding));
 }
 
+void SX128x::setRfSwitchPins(RADIOLIB_PIN_TYPE rxEn, RADIOLIB_PIN_TYPE txEn) {
+  _mod->setRfSwitchPins(rxEn, txEn);
+}
+
 uint8_t SX128x::getStatus() {
   uint8_t data = 0;
   SPIreadCommand(SX128X_CMD_GET_STATUS, &data, 1);

src/modules/SX128x/SX128x.h

@@ -741,6 +741,16 @@ class SX128x: public PhysicalLayer {
     */
     int16_t setEncoding(uint8_t encoding);
 
+    /*!
+      \brief Some modules contain external RF switch controlled by two pins. This function gives RadioLib control over those two pins to automatically switch Rx and Tx state.
+      When using automatic RF switch control, DO NOT change the pin mode of rxEn or txEn from Arduino sketch!
+
+      \param rxEn RX enable pin.
+
+      \param txEn TX enable pin.
+    */
+    void setRfSwitchPins(RADIOLIB_PIN_TYPE rxEn, RADIOLIB_PIN_TYPE txEn);
+
 #ifndef RADIOLIB_GODMODE
   protected:
 #endif