Added Heltec V4.3 support/FEM autodetection

Boards.h

@@ -151,6 +151,10 @@
     #endif
   #endif
 
+  #define LORA_PA_UNKNOWN  0x00
+  #define LORA_PA_GC1109   0x01
+  #define LORA_PA_KCT8103L 0x02
+
   #define HAS_DISPLAY false
   #define HAS_BLUETOOTH false
   #define HAS_BLE false
@@ -363,7 +367,7 @@
       #define HAS_SLEEP true
       #define PIN_WAKEUP GPIO_NUM_0
       #define WAKEUP_LEVEL 0
-      #define OCP_TUNED 0x18
+      #define OCP_TUNED 0x28
 
       const int pin_btn_usr1 = 0;
 
@@ -411,8 +415,9 @@
       #define HAS_LORA_LNA true
       #define PIN_WAKEUP GPIO_NUM_0
       #define WAKEUP_LEVEL 0
-      #define OCP_TUNED 0x18
+      #define OCP_TUNED 0x28
       #define Vext GPIO_NUM_36
+      #define LORA_PA_MODEL LORA_PA_UNKNOWN;
 
       const int pin_btn_usr1 = 0;
 
@@ -434,14 +439,17 @@
 
       #define LORA_LNA_GAIN  17
       #define LORA_LNA_GVT   12
-      #define LORA_PA_GC1109 true
       #define LORA_PA_PWR_EN  7
-      #define LORA_PA_CSD     2
+      #define LORA_PA_CSD     2 // Same pin on GC1109
-      #define LORA_PA_CPS    46
+      #define LORA_PA_CPS    46 // Same pin on GC1109
+      #define LORA_PA_CTX     5 // Only used on KCT8103
 
       #define PA_MAX_OUTPUT  28
       #define PA_GAIN_POINTS 22
-      #define PA_GAIN_VALUES 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 10, 9, 9, 8, 7
+      
+      #define LORA_LNA_KCT8103L_GAIN 21
+      const int PA_GC1109_VALUES[PA_GAIN_POINTS] =   {11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 10,  9, 9, 8, 7};
+      const int PA_KCT8103L_VALUES[PA_GAIN_POINTS] = {13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 12, 12, 11, 11, 10, 9, 8, 7};
 
       const int pin_cs = 8;
       const int pin_busy = 13;
@@ -529,13 +537,10 @@
       const int pin_np = 12;
       const int pin_dac = 25;
       const int pin_adc = 34;
-      // CBA already defined by framework
+      const int SD_MISO = 2;
-      //const int SD_MISO = 2;
+      const int SD_MOSI = 15;
-      // CBA already defined by framework
-      //const int SD_MOSI = 15;
       const int SD_CLK = 14;
-      // CBA already defined by framework
+      const int SD_CS = 13;
-      //const int SD_CS = 13;
       #if HAS_NP == false
         #if defined(EXTERNAL_LEDS)
           const int pin_led_rx = 12;
@@ -980,7 +985,7 @@
   // Default OCP value if not specified
   // in board configuration
   #ifndef OCP_TUNED
-    #define OCP_TUNED 0x18
+    #define OCP_TUNED 0x28
   #endif
 
   #ifndef PA_MAX_OUTPUT

RNode_Firmware.ino

@@ -1586,7 +1586,7 @@ void serial_callback(uint8_t sbyte) {
             if (txp > 13) txp = 13;
           #endif
         #else
-          if (txp > 17) txp = 17;
+          if (txp > 20) txp = 20;
         #endif
 
         lora_txp = txp;
@@ -2648,7 +2648,13 @@ void sleep_now() {
       #if BOARD_MODEL == BOARD_HELTEC32_V4
           headless_led_off();
           headless_led_detach_pwm();
+          #if LORA_PA_AUTO_DETECT
+            if (sx126x_modem.isKCT8103L()) {
+              digitalWrite(LORA_PA_CTX, LOW);
+            } else {
               digitalWrite(LORA_PA_CPS, LOW);
+            }
+          #endif
           digitalWrite(LORA_PA_CSD, LOW);
           digitalWrite(LORA_PA_PWR_EN, LOW);
           digitalWrite(Vext, HIGH);

Utilities.h

@@ -1383,11 +1383,33 @@ int getTxPower() {
 }
 
 #if HAS_LORA_PA
+    #if BOARD_MODEL == BOARD_HELTEC32_V4
+	bool pa_values_determined = false;
+	int tx_gain[PA_GAIN_POINTS] = {100};
+    #else
+	bool pa_values_determined = true;
 	const int tx_gain[PA_GAIN_POINTS] = {PA_GAIN_VALUES};
+    #endif
 #endif
 
+extern uint8_t lora_pa_model;
+void determine_pa_values() {
+	#if BOARD_MODEL == BOARD_HELTEC32_V4
+		if (lora_pa_model == LORA_PA_GC1109) {
+			for (int i=0; i < PA_GAIN_POINTS; i++) { tx_gain[i] = PA_GC1109_VALUES[i]; }
+			pa_values_determined = true;
+			for (int i=0; i < PA_GAIN_POINTS; i++) { Serial.print(" "); Serial.printf("%d", tx_gain[i]); }
+		} else if (lora_pa_model == LORA_PA_KCT8103L) {
+			for (int i=0; i < PA_GAIN_POINTS; i++) { tx_gain[i] = PA_KCT8103L_VALUES[i]; }
+			pa_values_determined = true;
+			for (int i=0; i < PA_GAIN_POINTS; i++) { Serial.print(" "); Serial.printf("%d", tx_gain[i]); }
+		}
+	#endif
+}
+
 int map_target_power_to_modem_output(int target_tx_power) {
 	#if HAS_LORA_PA
+		if (!pa_values_determined) { determine_pa_values(); }
 		int modem_output_dbm = -9;
 		for (int i = 0; i < PA_GAIN_POINTS; i++) {
 			int gain = tx_gain[i];

sx126x.cpp

@@ -275,6 +275,21 @@ void sx126x::setPacketParams(long preamble_symbols, uint8_t headermode, uint8_t
   buf[7] = 0x00; 
   buf[8] = 0x00; 
   executeOpcode(OP_PACKET_PARAMS_6X, buf, 9);
+
+  // SX1262 errata section 15.4: IQ polarity is inverted compared to
+  // SX1276. The SetPacketParams command resets register 0x0736 to an
+  // incorrect default. For standard IQ (no inversion), bit 2 must be
+  // SET after every SetPacketParams call. For inverted IQ, bit 2 must
+  // be CLEARED. Without this fix, LoRa RX demodulation fails silently
+  // while TX continues to work.
+  uint8_t iqreg = readRegister(0x0736);
+  if (buf[5] == 0x00) {
+    // Standard IQ: set bit 2
+    writeRegister(0x0736, iqreg | 0x04);
+  } else {
+    // Inverted IQ: clear bit 2
+    writeRegister(0x0736, iqreg & ~0x04);
+  }
 }
 
 void sx126x::reset(void) {
@@ -287,6 +302,22 @@ void sx126x::reset(void) {
   }
 }
 
+void sx126x::setDCDCRegulator(void) {
+  // Documentation
+  // 5. Power Distribution -> 5.1 Selecting DC-DC Converter or LDO Regulation
+  // 13.1.11 SetRegulatorMode
+
+  uint8_t mode_byte = MODE_STDBY_RC_6X;
+  executeOpcode(OP_STANDBY_6X, &mode_byte, 1);
+
+  // Enable DC-DC regulator for high power operation
+  uint8_t reg_mode = 0x01; // 0x00 = LDO, 0x01 = DC-DC
+  executeOpcode(OP_REGULATOR_MODE_6X, &reg_mode, 1);
+
+  delay(5);
+  waitOnBusy();
+}
+
 void sx126x::calibrate(void) {
   // Put in STDBY_RC mode before calibration
   uint8_t mode_byte = MODE_STDBY_RC_6X;
@@ -319,10 +350,19 @@ int sx126x::begin(long frequency) {
   if (_rxen != -1) { pinMode(_rxen, OUTPUT); }
   if (_txen != -1) { pinMode(_txen, OUTPUT); }
 
+    //TODO: if it works, make it optional
+  //#ifdef SX1262_USE_DCDC_REGULATOR
+    setDCDCRegulator();
+  //#endif
 
   calibrate();
   calibrate_image(frequency);
+  #if HAS_TCXO
     enableTCXO();
+    //13.1.15 SetRxTxFallbackMode to STDBY_XOSC
+    uint8_t fallback_mode = 0x30; // STDBY_XOSC after TX/RX
+    executeOpcode(OP_RX_TX_FALLBACK_MODE_6X, &fallback_mode, 1);
+  #endif
   loraMode();
   standby();
 
@@ -339,7 +379,9 @@ int sx126x::begin(long frequency) {
   setFrequency(frequency);
   setTxPower(2);
   enableCrc();
-  writeRegister(REG_LNA_6X, 0x96); // Set LNA boost
+  writeRegister(REG_LNA_6X, 0x96); // Set LNA boosted gain mode
+  // Undocumented SX1262 register patch recommended by Heltec/Semtech for improved RX sensitivity.
+  writeRegister(0x08B5, readRegister(0x08B5) | 0x01);
   uint8_t basebuf[2] = {0}; // Set base addresses
   executeOpcode(OP_BUFFER_BASE_ADDR_6X, basebuf, 2);
 
@@ -347,7 +389,22 @@ int sx126x::begin(long frequency) {
   setPacketParams(_preambleLength, _implicitHeaderMode, _payloadLength, _crcMode);
 
   #if HAS_LORA_PA
-    #if LORA_PA_GC1109
+    if (lora_pa_model == LORA_PA_UNKNOWN) {
+      #if BOARD_MODEL == BOARD_HELTEC32_V4
+        
+        pinMode(LORA_PA_PWR_EN, OUTPUT);
+        pinMode(LORA_PA_CSD, INPUT);
+        digitalWrite(LORA_PA_PWR_EN, HIGH); delay(5);
+        if (digitalRead(LORA_PA_CSD) == HIGH) {
+          lora_pa_model = LORA_PA_KCT8103L;
+          lora_lna_gain = LORA_LNA_KCT8103L_GAIN;
+        } else {
+          lora_pa_model = LORA_PA_GC1109;
+        }
+      #endif
+    }
+
+    if (lora_pa_model == LORA_PA_GC1109) {
       // Enable Vfem_ctl for supply to
       // PA power net.
       pinMode(LORA_PA_PWR_EN, OUTPUT);
@@ -372,7 +429,26 @@ int sx126x::begin(long frequency) {
       // is driven by the SX1262 DIO2
       // pin directly, so we do not
       // need to manually raise this.
-    #endif
+
+    } else if (lora_pa_model == LORA_PA_KCT8103L) {
+      // Enable Vfem_ctl for supply to
+      // PA power net.
+      pinMode(LORA_PA_PWR_EN, OUTPUT);
+      digitalWrite(LORA_PA_PWR_EN, HIGH);
+
+      // Enable KCT8103L chip
+      pinMode(LORA_PA_CSD, OUTPUT);
+      digitalWrite(LORA_PA_CSD, HIGH);
+
+      // Enable receive LNA
+      pinMode(LORA_PA_CTX, OUTPUT);
+      digitalWrite(LORA_PA_CTX, LOW);
+
+      // On Heltec V4.3, the PA CPS pin
+      // is driven by the SX1262 DIO2
+      // pin directly, so we do not
+      // need to manually raise this.
+    }
   #endif
 
   return 1;
@@ -382,14 +458,17 @@ void sx126x::end() { sleep(); SPI.end(); _preinit_done = false; }
 
 int sx126x::beginPacket(int implicitHeader) {
   #if HAS_LORA_PA
-    #if LORA_PA_GC1109
+    if (lora_pa_model == LORA_PA_GC1109) {
       // Enable PA CPS for transmit
       // digitalWrite(LORA_PA_CPS, HIGH);
       // Disabled since we're keeping it
       // on permanently as long as the
       // radio is powered up.
+    } else if (lora_pa_model == LORA_PA_KCT8103L) {
+      digitalWrite(LORA_PA_CTX, HIGH);
+    }
   #endif
-  #endif
+
   if (_txen != -1) { digitalWrite(_txen, HIGH); } //Set TXen high when transmitting
 
   standby();
@@ -405,6 +484,7 @@ int sx126x::beginPacket(int implicitHeader) {
 
 int sx126x::endPacket() {
   setPacketParams(_preambleLength, _implicitHeaderMode, _payloadLength, _crcMode);
+
   if (_rxen != -1) { digitalWrite(_rxen, LOW); } //Set RXen low when transmitting
 
   uint8_t timeout[3] = {0}; // Put in single TX mode
@@ -479,7 +559,7 @@ int ISR_VECT sx126x::currentRssi() {
   executeOpcodeRead(OP_CURRENT_RSSI_6X, &byte, 1);
   int rssi = -(int(byte)) / 2;
   #if HAS_LORA_LNA
-    rssi -= LORA_LNA_GAIN;
+    rssi -= lora_lna_gain;
   #endif
   return rssi;
 }
@@ -495,7 +575,7 @@ int ISR_VECT sx126x::packetRssi() {
   executeOpcodeRead(OP_PACKET_STATUS_6X, buf, 3);
   int pkt_rssi = -buf[0] / 2;
   #if HAS_LORA_LNA
-    pkt_rssi -= LORA_LNA_GAIN;
+    pkt_rssi -= lora_lna_gain;
   #endif
   return pkt_rssi;
 }
@@ -602,7 +682,7 @@ void sx126x::onReceive(void(*callback)(int)){
 
 void sx126x::receive(int size) {
   #if HAS_LORA_PA
-    #if LORA_PA_GC1109
+    if (lora_pa_model == LORA_PA_GC1109) {
       // Disable PA CPS for receive
       // digitalWrite(LORA_PA_CPS, LOW);
       // That turned out to be a bad idea.
@@ -610,7 +690,9 @@ void sx126x::receive(int size) {
       // on and off too quickly. We'll keep
       // it on permanently, as long as the
       // radio is powered up.
-    #endif
+    } else if (lora_pa_model == LORA_PA_KCT8103L) {
+      digitalWrite(LORA_PA_CTX, LOW);
+    }
   #endif
 
   if (size > 0) {

sx126x.h

@@ -74,6 +74,7 @@ public:
   void disableCrc();
   void enableTCXO();
   void disableTCXO();
+  void setDCDCRegulator();
 
   void rxAntEnable();
   void loraMode();
@@ -97,6 +98,8 @@ public:
 
   void dumpRegisters(Stream& out);
 
+  bool isKCT8103L() { return _kct8103l; }
+
 private:
   void explicitHeaderMode();
   void implicitHeaderMode();
@@ -107,7 +110,8 @@ public:
   // Poll for deferred DIO0 interrupt (call from main loop)
   void pollDio0();
 
-private:  uint8_t readRegister(uint16_t address);
+private:  
+  uint8_t readRegister(uint16_t address);
   void writeRegister(uint16_t address, uint8_t value);
   uint8_t singleTransfer(uint8_t opcode, uint16_t address, uint8_t value);
 
@@ -142,6 +146,7 @@ private:
   int _fifo_rx_addr_ptr;
   uint8_t _packet[255];
   bool _preinit_done;
+  bool _kct8103l;
   volatile bool _dio0_risen;
   void (*_onReceive)(int);
 };