Add radio function to read the radio syncword uint16_t syncword = Radio.GetSyncWord(void);

Author: beegee-tokyo

CHANGELOG.md

@@ -4,6 +4,9 @@ Arduino library for LoRa communication with Semtech SX126x chips. It is based on
 
 # Release Notes
 
+# V2.0.29 Add read the Syncword function
+  - Add radio function to read the radio syncword uint16_t syncword = Radio.GetSyncWord(void);
+  
 # V2.0.28 Add custom Syncword and Low DataRate optimization
   - Add radio function to set a custom Syncword Radio.SetCustomSyncWord(uint16_t syncword);
   - Add radio function to enforce Low DataRate optimization Radio.EnforceLowDRopt(bool enforce);

README.md

@@ -88,6 +88,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ----
 ## Changelog
 [Code releases](CHANGELOG.md)
+- 2025-01-05 Add function to read the Syncword
+  - Add radio function to read the radio syncword uint16_t syncword = Radio.GetSyncWord(void);
 - 2025-01-01 Add custom Syncword and Low DataRate optimization
   - Add radio function to set a custom Syncword Radio.SetCustomSyncWord(uint16_t syncword);
   - Add radio function to enforce Low DataRate optimization Radio.EnforceLowDRopt(bool enforce);

library.json

@@ -1,6 +1,6 @@
 {
 	"name": "SX126x-Arduino",
-	"version": "2.0.28",
+	"version": "2.0.29",
 	"keywords": [
 		"lora",
 		"Semtech",

library.properties

@@ -1,5 +1,5 @@
 name=SX126x-Arduino
-version=2.0.28
+version=2.0.29
 author=Bernd Giesecke <beegee@giesecke.tk>
 maintainer=Bernd Giesecke <beegee@giesecke.tk>
 sentence=Arduino library to use Semtech SX126x LoRa chips and modules to communicate

src/boards/mcu/board.cpp

@@ -92,7 +92,9 @@ uint32_t lora_hardware_init(hw_config hwConfig)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040
 		if (start_lora_task())
@@ -138,7 +140,9 @@ uint32_t lora_hardware_re_init(hw_config hwConfig)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040
 		if (start_lora_task())
@@ -183,7 +187,9 @@ uint32_t lora_isp4520_init(int chipType)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040
 		if (start_lora_task())
@@ -230,7 +236,9 @@ uint32_t lora_rak4630_init(void)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040
 		if (start_lora_task())
@@ -283,7 +291,9 @@ uint32_t lora_rak11300_init(void)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 		// If we are compiling for ESP32, nRF52 or RP2040 we start background task
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040
@@ -344,7 +354,9 @@ uint32_t lora_rak13300_init(void)
 
 	LOG_LIB("BRD", "SyncWord = %04X", readSyncWord);
 
-	if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	// There could be a custom syncword, better test for 0xFFFF
+	// if ((readSyncWord == 0x2414) || (readSyncWord == 0x4434))
+	if (readSyncWord != 0xFFFF)
 	{
 #if defined NRF52_SERIES || defined ESP32 || defined ARDUINO_ARCH_RP2040 || defined ARDUINO_RAKWIRELESS_RAK11300
 		if (start_lora_task())

src/radio/radio.h

@@ -354,11 +354,17 @@ struct Radio_s
 	/*!
 	 * \brief Sets a custom Sync-Word. Updates the sync byte.
 	 *
-	 * \remark Applies to LoRa modem only
+	 * \remark ATTENTION, changes the LoRaWAN sync word as well. Use with care.
 	 *
 	 * \param  syncword 2 byte custom Sync-Word to be used
 	 */
 	void (*SetCustomSyncWord)(uint16_t syncword);
+	/*!
+	 * \brief Get Sync-Word.
+	 *
+	 * \retval  syncword current 2 byte custom Sync-Word
+	 */
+	uint16_t (*GetSyncWord)(void);
 	/*!
 	 * \brief Gets the time required for the board plus radio to get out of sleep.[ms]
 	 *

src/radio/sx126x/radio.cpp

@@ -325,12 +325,19 @@ void RadioSetPublicNetwork(bool enable);
 /*!
  * \brief Sets a custom Sync-Word. Updates the sync byte.
  *
- * \remark Applies to LoRa modem only
+ * \remark ATTENTION, changes the LoRaWAN sync word as well. Use with care.
  *
  * \param  syncword 2 byte custom Sync-Word to be used
  */
 void RadioSetCustomSyncWord(uint16_t syncword);
 
+/*!
+ * \brief Get current Sync-Word.
+ *
+ * \param  syncword 2 byte custom Sync-Word in use
+ */
+uint16_t RadioGetSyncWord(void);
+
 /*!
  * @brief Gets the time required for the board plus radio to get out of sleep.[ms]
  *
@@ -406,6 +413,7 @@ const struct Radio_s Radio =
 		RadioSetMaxPayloadLength,
 		RadioSetPublicNetwork,
 		RadioSetCustomSyncWord,
+		RadioGetSyncWord,
 		RadioGetWakeupTime,
 		RadioBgIrqProcess,
 		RadioIrqProcess,
@@ -1250,6 +1258,16 @@ void RadioSetCustomSyncWord(uint16_t syncword)
 	SX126xWriteRegister(REG_LR_SYNCWORD + 1, syncword & 0xFF);
 }
 
+uint16_t RadioGetSyncWord(void)
+{
+	uint8_t syncWord[8];
+	RadioSetModem(MODEM_LORA);
+	syncWord[0] = SX126xReadRegister(REG_LR_SYNCWORD);
+	syncWord[1] = SX126xReadRegister(REG_LR_SYNCWORD + 1);
+
+	return (uint16_t)(syncWord[0] << 8) + (uint16_t)(syncWord[1]);
+}
+
 uint32_t RadioGetWakeupTime(void)
 {
 	if (_hwConfig.USE_DIO3_TCXO)

src/radio/sx126x/sx126x.cpp

@@ -160,6 +160,12 @@ uint8_t SX126xSetSyncWord(uint8_t *syncWord)
 	return 0;
 }
 
+uint8_t SX126xGetSyncWord(uint8_t *syncWord)
+{
+	SX126xReadRegisters(REG_LR_SYNCWORDBASEADDRESS, syncWord, 8);
+	return 0;
+}
+
 void SX126xSetCrcSeed(uint16_t seed)
 {
 	uint8_t buf[2];

src/radio/sx126x/sx126x.h

@@ -784,6 +784,13 @@ void SX126xSendPayload(uint8_t *payload, uint8_t size, uint32_t timeout);
  */
 uint8_t SX126xSetSyncWord(uint8_t *syncWord);
 
+/*!
+ * \brief Gets the current Sync Word given by index used in GFSK
+ *
+ * \retval      2 byte syncword
+ */
+uint16_t SX126xGetSyncWord(void);
+
 /*!
  * \brief Sets the seed value for the LFSR used for the CRC calculation
  *