From 32e13eb7f9c1549b3d12c9f9359c2f974c961076 Mon Sep 17 00:00:00 2001
From: Rainer Fritz <rain3rfritz@gmail.com>
Date: Sun, 29 Dec 2024 19:18:20 +0100
Subject: [PATCH 1/2] added set custom syncword function

---
 src/radio/radio.h          |  8 ++++++++
 src/radio/sx126x/radio.cpp | 33 +++++++++++++++++++++++++++++----
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/src/radio/radio.h b/src/radio/radio.h
index 1cb69d7..38cd7e6 100644
--- a/src/radio/radio.h
+++ b/src/radio/radio.h
@@ -351,6 +351,14 @@ struct Radio_s
      * \param  enable if true, it enables a public network
      */
 	void (*SetPublicNetwork)(bool enable);
+     /*!
+     * \brief Sets a custom Sync-Word. Updates the sync byte.
+     *
+     * \remark Applies to LoRa modem only
+     *
+     * \param  syncword 2 byte custom Sync-Word to be used
+     */
+	void (*SetCustomSyncWord)(uint16_t syncword);
 	/*!
      * \brief Gets the time required for the board plus radio to get out of sleep.[ms]
      *
diff --git a/src/radio/sx126x/radio.cpp b/src/radio/sx126x/radio.cpp
index 0dea0f5..3d5117e 100644
--- a/src/radio/sx126x/radio.cpp
+++ b/src/radio/sx126x/radio.cpp
@@ -319,6 +319,15 @@ void RadioSetMaxPayloadLength(RadioModems_t modem, uint8_t max);
  */
 void RadioSetPublicNetwork(bool enable);
 
+/*!
+ * \brief Sets a custom Sync-Word. Updates the sync byte.
+ *
+ * \remark Applies to LoRa modem only
+ *
+ * \param  syncword 2 byte custom Sync-Word to be used
+ */
+void SetCustomSyncWord(uint16_t syncword);
+
 /*!
  * @brief Gets the time required for the board plus radio to get out of sleep.[ms]
  *
@@ -386,6 +395,7 @@ const struct Radio_s Radio =
 		RadioReadBuffer,
 		RadioSetMaxPayloadLength,
 		RadioSetPublicNetwork,
+		SetCustomSyncWord,
 		RadioGetWakeupTime,
 		RadioBgIrqProcess,
 		RadioIrqProcess,
@@ -465,6 +475,8 @@ bool TimerTxTimeout = false;
 
 RadioModems_t _modem;
 
+bool hasCustomSyncWord = false;
+
 /*
  * SX126x DIO IRQ callback functions prototype
  */
@@ -612,12 +624,17 @@ void RadioSetModem(RadioModems_t modem)
 		break;
 	case MODEM_LORA:
 		SX126xSetPacketType(PACKET_TYPE_LORA);
-		// Public/Private network register is reset when switching modems
-		if (RadioPublicNetwork.Current != RadioPublicNetwork.Previous)
+		// check first if a custom SyncWord is set
+		if (!hasCustomSyncWord)
 		{
-			RadioPublicNetwork.Current = RadioPublicNetwork.Previous;
-			RadioSetPublicNetwork(RadioPublicNetwork.Current);
+			// Public/Private network register is reset when switching modems
+			if (RadioPublicNetwork.Current != RadioPublicNetwork.Previous)
+			{
+				RadioPublicNetwork.Current = RadioPublicNetwork.Previous;
+				RadioSetPublicNetwork(RadioPublicNetwork.Current);
+			}
 		}
+
 		_modem = modem;
 		break;
 	}
@@ -1195,6 +1212,7 @@ void RadioSetMaxPayloadLength(RadioModems_t modem, uint8_t max)
 
 void RadioSetPublicNetwork(bool enable)
 {
+	hasCustomSyncWord = false;
 	RadioPublicNetwork.Current = RadioPublicNetwork.Previous = enable;
 
 	RadioSetModem(MODEM_LORA);
@@ -1212,6 +1230,13 @@ void RadioSetPublicNetwork(bool enable)
 	}
 }
 
+void SetCustomSyncWord(uint16_t syncword){
+	hasCustomSyncWord = true;
+	RadioSetModem(MODEM_LORA);
+	SX126xWriteRegister(REG_LR_SYNCWORD, (syncword >> 8) & 0xFF);
+	SX126xWriteRegister(REG_LR_SYNCWORD + 1, syncword & 0xFF);
+}
+
 uint32_t RadioGetWakeupTime(void)
 {
 	if (_hwConfig.USE_DIO3_TCXO)

From ca35a64e52e5e4e309bf503eacb8b4a575f555a0 Mon Sep 17 00:00:00 2001
From: Rainer Fritz <rain3rfritz@gmail.com>
Date: Tue, 31 Dec 2024 15:44:52 +0100
Subject: [PATCH 2/2] corrected Function name RadioSetCustomSyncWord

---
 src/radio/sx126x/radio.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/radio/sx126x/radio.cpp b/src/radio/sx126x/radio.cpp
index 3d5117e..53a2962 100644
--- a/src/radio/sx126x/radio.cpp
+++ b/src/radio/sx126x/radio.cpp
@@ -326,7 +326,7 @@ void RadioSetPublicNetwork(bool enable);
  *
  * \param  syncword 2 byte custom Sync-Word to be used
  */
-void SetCustomSyncWord(uint16_t syncword);
+void RadioSetCustomSyncWord(uint16_t syncword);
 
 /*!
  * @brief Gets the time required for the board plus radio to get out of sleep.[ms]
@@ -395,7 +395,7 @@ const struct Radio_s Radio =
 		RadioReadBuffer,
 		RadioSetMaxPayloadLength,
 		RadioSetPublicNetwork,
-		SetCustomSyncWord,
+		RadioSetCustomSyncWord,
 		RadioGetWakeupTime,
 		RadioBgIrqProcess,
 		RadioIrqProcess,
@@ -1230,7 +1230,7 @@ void RadioSetPublicNetwork(bool enable)
 	}
 }
 
-void SetCustomSyncWord(uint16_t syncword){
+void RadioSetCustomSyncWord(uint16_t syncword){
 	hasCustomSyncWord = true;
 	RadioSetModem(MODEM_LORA);
 	SX126xWriteRegister(REG_LR_SYNCWORD, (syncword >> 8) & 0xFF);