Add external RF switch management for RF95 (needed for RAK815)

docs/software/nrf52-TODO.md

@@ -3,9 +3,9 @@
 ## RAK815
 
 TODO:
-* LORA: P0.23 is for PABOOST? see page 2 in RAK813 sechematic  P0.22 is for HF_RF_CPS?  Look up datasheet for PE4259  Until this is fixed I bet the range is quite poor.  DIO2 is not controlling PABOOST on this board!
-* i2c gps comms not quite right
-* measure power draw
+
+- i2c gps comms not quite right
+- measure power draw
 
 ### Bootloader
 

src/mesh/RF95Interface.cpp

@@ -12,6 +12,18 @@ RF95Interface::RF95Interface(RADIOLIB_PIN_TYPE cs, RADIOLIB_PIN_TYPE irq, RADIOL
     // FIXME - we assume devices never get destroyed
 }
 
+/** Some boards require GPIO control of tx vs rx paths */
+void RF95Interface::setTransmitEnable(bool txon)
+{
+#ifdef RF95_TXEN
+    digitalWrite(RF95_TXEN, txon ? 1 : 0);
+#endif
+
+#ifdef RF95_RXEN
+    digitalWrite(RF95_RXEN, txon ? 0 : 1);
+#endif
+}
+
 /// Initialise the Driver transport hardware and software.
 /// Make sure the Driver is properly configured before calling init().
 /// \return true if initialisation succeeded.
@@ -30,6 +42,22 @@ bool RF95Interface::init()
     digitalWrite(RF95_TCXO, 1);
 #endif
 
+    /*
+    #define RF95_TXEN (22) // If defined, this pin should be set high prior to transmit (controls an external analog switch)
+    #define RF95_RXEN (23) // If defined, this pin should be set high prior to receive (controls an external analog switch)
+    */
+
+#ifdef RF95_TXEN
+    pinMode(RF95_TXEN, OUTPUT);
+    digitalWrite(RF95_TXEN, 0);
+#endif
+
+#ifdef RF95_RXEN
+    pinMode(RF95_RXEN, OUTPUT);
+    digitalWrite(RF95_RXEN, 1);
+#endif
+    setTransmitEnable(false);
+
     int res = lora->begin(freq, bw, sf, cr, syncWord, power, currentLimit, preambleLength);
     DEBUG_MSG("RF95 init result %d\n", res);
 
@@ -104,8 +132,18 @@ void RF95Interface::setStandby()
     completeSending(); // If we were sending, not anymore
 }
 
+/** We override to turn on transmitter power as needed.
+ */
+void RF95Interface::configHardwareForSend()
+{
+    setTransmitEnable(true);
+
+    RadioLibInterface::configHardwareForSend();
+}
+
 void RF95Interface::startReceive()
 {
+    setTransmitEnable(false);
     setStandby();
     int err = lora->startReceive();
     assert(err == ERR_NONE);

src/mesh/RF95Interface.h

@@ -52,4 +52,13 @@ class RF95Interface : public RadioLibInterface
     virtual void addReceiveMetadata(MeshPacket *mp);
 
     virtual void setStandby();
+
+    /**
+     *  We override to turn on transmitter power as needed.
+     */
+    virtual void configHardwareForSend();
+
+  private:
+    /** Some boards require GPIO control of tx vs rx paths */
+    void setTransmitEnable(bool txon);
 };

src/mesh/SX1262Interface.cpp

@@ -119,8 +119,7 @@ void SX1262Interface::addReceiveMetadata(MeshPacket *mp)
     mp->rx_snr = lora.getSNR();
 }
 
-/** start an immediate transmit
- *  We override to turn on transmitter power as needed.
+/** We override to turn on transmitter power as needed.
  */
 void SX1262Interface::configHardwareForSend()
 {