[SX126x] Added option to disable TCXO using SX126x::setTCXO(0) (#99)

src/modules/SX126x/SX126x.cpp

@@ -1203,6 +1203,11 @@ int16_t SX126x::setTCXO(float voltage, uint32_t delay) {
     clearDeviceErrors();
   }
 
+  // check 0 V disable
+  if(abs(voltage - 0.0) <= 0.001) {
+    return(reset(true));
+  }
+
   // check alowed voltage values
   uint8_t data[4];
   if(abs(voltage - 1.6) <= 0.001) {

src/modules/SX126x/SX126x.h

@@ -733,9 +733,12 @@ class SX126x: public PhysicalLayer {
     /*!
       \brief Sets TCXO (Temperature Compensated Crystal Oscillator) configuration.
 
-      \param TCXO reference voltage in volts. Allowed values are 1.6, 1.7, 1.8, 2.2. 2.4, 2.7, 3.0 and 3.3 V
+      \param TCXO reference voltage in volts. Allowed values are 1.6, 1.7, 1.8, 2.2. 2.4, 2.7, 3.0 and 3.3 V. Set to 0 to disable TCXO.
+      NOTE: After setting this parameter to 0, the module will be reset (since there's no other way to disable TCXO).
 
       \param TCXO timeout in us. Defaults to 5000 us.
+
+      \returns \ref status_codes
     */
     int16_t setTCXO(float voltage, uint32_t delay = 5000);