[PHY] Added method to set direct mode parameters (#177)

src/protocols/PhysicalLayer/PhysicalLayer.cpp

@@ -167,3 +167,13 @@ int32_t PhysicalLayer::random(int32_t min, int32_t max) {
 
   return(PhysicalLayer::random(max - min) + min);
 }
+
+int16_t PhysicalLayer::startDirect() {
+  // disable encodings
+  int16_t state = setEncoding(0);
+  RADIOLIB_ASSERT(state);
+
+  // set frequency deviation to the lowest possible value
+  state = setFrequencyDeviation(0);
+  return(state);
+}

src/protocols/PhysicalLayer/PhysicalLayer.h

@@ -251,6 +251,13 @@ class PhysicalLayer {
   */
    virtual uint8_t random() = 0;
 
+   /*!
+     \brief Configure module parameters for direct modes. Must be called prior to "ham" modes like RTTY or AX.25. Only available in FSK mode.
+
+     \returns \ref status_codes
+   */
+   int16_t startDirect();
+
 #ifndef RADIOLIB_GODMODE
   private:
 #endif