[SX127x] Implemented RF switch control

examples/SX127x/SX127x_Transmit/SX127x_Transmit.ino

@@ -49,6 +49,16 @@ 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/SX127x/SX127x.cpp

@@ -368,6 +368,9 @@ int16_t SX127x::startReceive(uint8_t len, uint8_t mode) {
     }
   }
 
+  // set RF switch (if present)
+  _mod->setRfSwitchState(false);
+
   // set mode to receive
   return(setMode(mode));
 }
@@ -421,6 +424,9 @@ int16_t SX127x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
     // write packet to FIFO
     _mod->SPIwriteRegisterBurst(SX127X_REG_FIFO, data, len);
 
+    // set RF switch (if present)
+    _mod->setRfSwitchState(true);
+
     // start transmission
     state |= setMode(SX127X_TX);
     RADIOLIB_ASSERT(state);
@@ -451,6 +457,9 @@ int16_t SX127x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
     // write packet to FIFO
     _mod->SPIwriteRegisterBurst(SX127X_REG_FIFO, data, len);
 
+    // set RF switch (if present)
+    _mod->setRfSwitchState(true);
+
     // start transmission
     state |= setMode(SX127X_TX);
     RADIOLIB_ASSERT(state);
@@ -934,6 +943,10 @@ uint8_t SX127x::getModemStatus() {
   return(_mod->SPIreadRegister(SX127X_REG_MODEM_STAT));
 }
 
+void SX127x::setRfSwitchPins(RADIOLIB_PIN_TYPE rxEn, RADIOLIB_PIN_TYPE txEn) {
+  _mod->setRfSwitchPins(rxEn, txEn);
+}
+
 int8_t SX127x::getTempRaw() {
   int8_t temp = 0;
   uint8_t previousOpMode;

src/modules/SX127x/SX127x.h

@@ -921,6 +921,16 @@ class SX127x: public PhysicalLayer {
     */
     int8_t getTempRaw();
 
+    /*!
+      \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);
+
     #ifdef RADIOLIB_DEBUG
       void regDump();
     #endif