Add T-Beam 1W external LNA control

src/helpers/radiolib/CustomSX1262.h

@@ -156,6 +156,45 @@ class CustomSX1262 : public SX1262 {
       return _rx_ps_rf_rx_disabled;
     }
 
+    // Select whether a host-controlled RXEN pin is asserted in receive mode.
+    // Some FEM modules (notably the LilyGo T-Beam 1W XY16P35) expose their
+    // external LNA supply on RXEN while DIO2 independently selects the RF
+    // switch.  Swapping RadioLib's table keeps the requested state intact
+    // across RX, CAD, TX, standby, and duty-cycle transitions; a one-shot
+    // digitalWrite() would be overwritten on the next mode change.
+    bool setExternalRxLnaEnabled(bool enabled) {
+    #if defined(SX126X_RXEN)
+      #if defined(SX126X_TXEN)
+        static constexpr uint32_t tx_en = SX126X_TXEN;
+      #else
+        static constexpr uint32_t tx_en = RADIOLIB_NC;
+      #endif
+
+      static const uint32_t pins[Module::RFSWITCH_MAX_PINS] = {
+        SX126X_RXEN, tx_en, RADIOLIB_NC, RADIOLIB_NC, RADIOLIB_NC,
+      };
+      static const Module::RfSwitchMode_t lna_enabled_table[] = {
+        { Module::MODE_IDLE, { LOW,  LOW } },
+        { Module::MODE_RX,   { HIGH, LOW } },
+        { Module::MODE_TX,   { LOW,  HIGH } },
+        END_OF_MODE_TABLE,
+      };
+      static const Module::RfSwitchMode_t lna_disabled_table[] = {
+        { Module::MODE_IDLE, { LOW, LOW } },
+        { Module::MODE_RX,   { LOW, LOW } },
+        { Module::MODE_TX,   { LOW, HIGH } },
+        END_OF_MODE_TABLE,
+      };
+
+      this->mod->setRfSwitchTable(
+          pins, enabled ? lna_enabled_table : lna_disabled_table);
+      return true;
+    #else
+      (void)enabled;
+      return false;
+    #endif
+    }
+
     // BUSY high means the chip is asleep (RX duty-cycle sleep window) or mid
     // command; any SPI access would stall until the chip's next listen window.
     bool isChipBusy() {

src/helpers/radiolib/CustomSX1262Wrapper.h

@@ -78,6 +78,25 @@ public:
     return ((CustomSX1262 *)_radio)->isRxPowerSavingRfRxDisabled();
   }
 
+  // Reconfigure through the normal bounded radio transition so RXEN is never
+  // asserted while a transmission or unread packet owns the radio.  The
+  // selected table is then honored by every RadioLib mode transition.
+  bool setExternalRxLnaEnabled(bool enabled) {
+  #if defined(SX126X_RXEN)
+    if (SX126X_RXEN == RADIOLIB_NC) return false;
+
+    uint8_t resume_rx = beginReconfigure();
+    if (resume_rx > 1) return false;
+
+    bool success = ((CustomSX1262 *)_radio)->setExternalRxLnaEnabled(enabled);
+    endReconfigure(resume_rx);
+    return success;
+  #else
+    (void)enabled;
+    return false;
+  #endif
+  }
+
 protected:
   int startReceiveMode() override {
     if (_rx_ps_armed) {
@@ -118,7 +137,16 @@ protected:
   bool radioDeepInit() override {
     // std_init() re-runs RadioLib begin(), which starts with a hardware reset
     // via NRST - the only way out of a hard-locked chip (BUSY stuck high).
-    return ((CustomSX1262 *)_radio)->std_init();
+    bool success = ((CustomSX1262 *)_radio)->std_init();
+#if defined(TBEAM_1W)
+    // std_init() restores RadioLib's default RXEN table. Reapply the T-Beam
+    // 1W's persisted external-LNA selection before receive mode is re-armed.
+    if (success && _board->canControlLoRaFemLna()) {
+      success = ((CustomSX1262 *)_radio)->setExternalRxLnaEnabled(
+          _board->isLoRaFemLnaEnabled());
+    }
+#endif
+    return success;
   }
   bool supportsRadioDeepInit() const override { return true; }
 

variants/lilygo_tbeam_1w/TBeam1WBoard.cpp

@@ -1,4 +1,5 @@
 #include "TBeam1WBoard.h"
+#include <helpers/radiolib/CustomSX1262Wrapper.h>
 
 void TBeam1WBoard::begin() {
   ESP32Board::begin();
@@ -9,7 +10,10 @@ void TBeam1WBoard::begin() {
   radio_powered = true;
   delay(10);  // Allow radio to power up
 
-  // RF switch RXEN pin handled by RadioLib via setRfSwitchPins()
+  // Keep the external LNA off until RadioLib deliberately enters RX. GPIO21
+  // is subsequently controlled by RadioLib's target-specific RF switch table.
+  pinMode(SX126X_RXEN, OUTPUT);
+  digitalWrite(SX126X_RXEN, LOW);
 
   // Initialize LED
   pinMode(LED_PIN, OUTPUT);
@@ -62,6 +66,29 @@ void TBeam1WBoard::powerOff() {
   ESP32Board::powerOff();
 }
 
+void TBeam1WBoard::attachRadioDriver(CustomSX1262Wrapper* driver) {
+  radio_driver = driver;
+}
+
+bool TBeam1WBoard::setLoRaFemLnaEnabled(bool enable) {
+  if (radio_driver == nullptr || !radio_driver->setExternalRxLnaEnabled(enable)) {
+    return false;
+  }
+
+  // This is the requested RX-mode state. TX and standby always force CTRL low
+  // regardless of this preference, protecting both the LNA and PA paths.
+  lna_enabled = enable;
+  return true;
+}
+
+bool TBeam1WBoard::canControlLoRaFemLna() const {
+  return radio_driver != nullptr;
+}
+
+bool TBeam1WBoard::isLoRaFemLnaEnabled() const {
+  return lna_enabled;
+}
+
 void TBeam1WBoard::setFanEnabled(bool enabled) {
   digitalWrite(FAN_CTRL_PIN, enabled ? HIGH : LOW);
 }

variants/lilygo_tbeam_1w/TBeam1WBoard.h

@@ -4,6 +4,8 @@
 #include <helpers/ESP32Board.h>
 #include "variant.h"
 
+class CustomSX1262Wrapper;
+
 // LilyGo T-Beam 1W with SX1262 + external PA (XY16P35 module)
 //
 // Power architecture (LDO is separate chip on T-Beam board, not inside XY16P35):
@@ -30,6 +32,8 @@
 class TBeam1WBoard : public ESP32Board {
 private:
   bool radio_powered = false;
+  bool lna_enabled = true;
+  CustomSX1262Wrapper* radio_driver = nullptr;
 
 public:
   void begin();
@@ -39,6 +43,11 @@ public:
   const char* getManufacturerName() const override;
   void powerOff() override;
 
+  void attachRadioDriver(CustomSX1262Wrapper* driver);
+  bool setLoRaFemLnaEnabled(bool enable) override;
+  bool canControlLoRaFemLna() const override;
+  bool isLoRaFemLnaEnabled() const override;
+
   // Fan control methods
   void setFanEnabled(bool enabled);
   bool isFanEnabled() const;

variants/lilygo_tbeam_1w/target.cpp

@@ -36,6 +36,7 @@ bool radio_init() {
 
   bool success = radio.std_init(&spi);
   if (success) {
+    board.attachRadioDriver(&radio_driver);
     // T-Beam 1W has external PA requiring longer ramp time (>800us recommended)
     // RADIOLIB_SX126X_PA_RAMP_800U = 0x05
     radio.setTxParams(LORA_TX_POWER, RADIOLIB_SX126X_PA_RAMP_800U);