Merge pull request #4691 from S5NC/rak11200-pin-name-correction

Rak11200 pin name correction

src/mesh/SX126xInterface.cpp

@@ -25,9 +25,25 @@ SX126xInterface<T>::SX126xInterface(LockingArduinoHal *hal, RADIOLIB_PIN_TYPE cs
 /// \return true if initialisation succeeded.
 template <typename T> bool SX126xInterface<T>::init()
 {
-#ifdef SX126X_POWER_EN
-    pinMode(SX126X_POWER_EN, OUTPUT);
+
+// Typically, the RF switch on SX126x boards is controlled by two signals, which are negations of each other (switched RFIO
+// paths). The negation is usually performed in hardware, or (suboptimal design) TXEN and RXEN are the two inputs to this style of
+// RF switch. On some boards, there is no hardware negation between CTRL and ¬CTRL, but CTRL is internally connected to DIO2, and
+// DIO2's switching is done by the SX126X itself, so the MCU can't control ¬CTRL at exactly the same time. One solution would be
+// to set ¬CTRL as SX126X_TXEN or SX126X_RXEN, but they may already be used for another purpose, such as controlling another
+// PA/LNA. Keeping ¬CTRL high seems to work, as long CTRL=1, ¬CTRL=1 has the opposite and stable RF path effect as CTRL=0 and
+// ¬CTRL=1, this depends on the RF switch, but it seems this usually works. Better hardware design, which is done most the time,
+// means this workaround is not necessary.
+#ifdef SX126X_ANT_SW // Perhaps add RADIOLIB_NC check, and beforehand define as such if it is undefined, but it is not commonly
+                     // used and not part of the 'default' set of pin definitions.
+    digitalWrite(SX126X_ANT_SW, HIGH);
+    pinMode(SX126X_ANT_SW, OUTPUT);
+#endif
+
+#ifdef SX126X_POWER_EN // Perhaps add RADIOLIB_NC check, and beforehand define as such if it is undefined, but it is not commonly
+                       // used and not part of the 'default' set of pin definitions.
     digitalWrite(SX126X_POWER_EN, HIGH);
+    pinMode(SX126X_POWER_EN, OUTPUT);
 #endif
 
 #if ARCH_PORTDUINO