E22 SX1262 module now works!

Thanks mostly to an old github comment by @beegee-tokyo the fix was easy
(comment here https://github.com/jgromes/RadioLib/issues/12#issuecomment-520450429)

We now set DIO3 to 2.4 volts to power the oscillator inside the E22
module (undocumented in the E22 docs)

src/mesh/RadioLibInterface.h

@@ -91,9 +91,6 @@ class RadioLibInterface : public RadioInterface, private PeriodicTask
     virtual void startReceive() = 0;
 
   private:
-    /** start an immediate transmit */
-    void startSend(MeshPacket *txp);
-
     /** if we have something waiting to send, start a short random timer so we can come check for collision before actually doing
      * the transmit
      *
@@ -114,6 +111,11 @@ class RadioLibInterface : public RadioInterface, private PeriodicTask
     /// \return true if initialisation succeeded.
     virtual bool init();
 
+    /** start an immediate transmit
+     *  This method is virtual so subclasses can hook as needed, subclasses should not call directly
+     */
+    virtual void startSend(MeshPacket *txp);
+
     /**
      * Convert our modemConfig enum into wf, sf, etc...
      *

src/mesh/SX1262Interface.cpp

@@ -14,7 +14,19 @@ bool SX1262Interface::init()
 {
     RadioLibInterface::init();
 
+#ifdef SX1262_RXEN // set not rx or tx mode
+    pinMode(SX1262_RXEN, OUTPUT);
+    pinMode(SX1262_TXEN, OUTPUT);
+    digitalWrite(SX1262_RXEN, LOW);
+    digitalWrite(SX1262_TXEN, LOW);
+#endif
+
+#ifndef SX1262_E22
     float tcxoVoltage = 0; // None - we use an XTAL
+#else
+    float tcxoVoltage =
+        2.4; // E22 uses DIO3 to power tcxo per https://github.com/jgromes/RadioLib/issues/12#issuecomment-520695575
+#endif
     bool useRegulatorLDO = false; // Seems to depend on the connection to pin 9/DCC_SW - if an inductor DCDC?
 
     applyModemConfig();
@@ -23,6 +35,12 @@ bool SX1262Interface::init()
     int res = lora.begin(freq, bw, sf, cr, syncWord, power, currentLimit, preambleLength, tcxoVoltage, useRegulatorLDO);
     DEBUG_MSG("LORA init result %d\n", res);
 
+#ifdef SX1262_RXEN
+    // lora.begin assumes Dio2 is RF switch control, which is not true if we are manually controlling RX and TX
+    if (res == ERR_NONE)
+        res = lora.setDio2AsRfSwitch(false);
+#endif
+
     if (res == ERR_NONE)
         res = lora.setCRC(SX126X_LORA_CRC_ON);
 
@@ -81,6 +99,11 @@ void SX1262Interface::setStandby()
     int err = lora.standby();
     assert(err == ERR_NONE);
 
+#ifdef SX1262_RXEN // we have RXEN/TXEN control - turn off RX and TX power
+    digitalWrite(SX1262_RXEN, LOW);
+    digitalWrite(SX1262_TXEN, LOW);
+#endif
+
     isReceiving = false; // If we were receiving, not any more
     disableInterrupt();
     completeSending(); // If we were sending, not anymore
@@ -94,6 +117,19 @@ void SX1262Interface::addReceiveMetadata(MeshPacket *mp)
     mp->rx_snr = lora.getSNR();
 }
 
+/** start an immediate transmit
+ *  We override to turn on transmitter power as needed.
+ */
+void SX1262Interface::startSend(MeshPacket *txp)
+{
+#ifdef SX1262_RXEN // we have RXEN/TXEN control - turn on TX power / off RX power
+    digitalWrite(SX1262_RXEN, LOW);
+    digitalWrite(SX1262_TXEN, HIGH);
+#endif
+
+    RadioLibInterface::startSend(txp);
+}
+
 // For power draw measurements, helpful to force radio to stay sleeping
 // #define SLEEP_ONLY
 
@@ -102,6 +138,12 @@ void SX1262Interface::startReceive()
 #ifdef SLEEP_ONLY
     sleep();
 #else
+
+#ifdef SX1262_RXEN // we have RXEN/TXEN control - turn on RX power / off TX power
+    digitalWrite(SX1262_RXEN, HIGH);
+    digitalWrite(SX1262_TXEN, LOW);
+#endif
+
     setStandby();
     // int err = lora.startReceive();
     int err = lora.startReceiveDutyCycleAuto(); // We use a 32 bit preamble so this should save some power by letting radio sit in

src/mesh/SX1262Interface.h

@@ -43,6 +43,12 @@ class SX1262Interface : public RadioLibInterface
      * Start waiting to receive a message
      */
     virtual void startReceive();
+
+    /** start an immediate transmit
+     *  We override to turn on transmitter power as needed.
+     */
+    virtual void startSend(MeshPacket *txp);
+
     /**
      * Add SNR data to received messages
      */

variants/ppr/variant.h

@@ -137,6 +137,7 @@ static const uint8_t SCK = PIN_SPI_SCK;
 // #define SX1262_ANT_SW (32 + 10)
 #define SX1262_RXEN (22)
 #define SX1262_TXEN (24)
+#define SX1262_E22  // Indicates this SX1262 is inside of an ebyte E22 module and special config should be done for that
 
 // ERC12864-10 LCD
 #define ERC12864_CS (32 + 4)