From 9d85b6451c08011d88f699372235363a50c09458 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Sat, 26 Dec 2020 12:12:52 +0000
Subject: [PATCH] Update the M17 sync words.

---
 M17Control.cpp |  8 ++++----
 M17Defines.h   |  5 +++--
 Sync.cpp       | 15 +++++++++++----
 Sync.h         |  5 +++--
 Version.h      |  2 +-
 5 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/M17Control.cpp b/M17Control.cpp
index 9be8607..a36d0eb 100644
--- a/M17Control.cpp
+++ b/M17Control.cpp
@@ -269,7 +269,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 				data[1U] = 0x00U;
 
 				// Generate the sync
-				CSync::addM17HeaderSync(data + 2U);
+				CSync::addM17LinkSetupSync(data + 2U);
 				
 				unsigned char setup[M17_LICH_LENGTH_BYTES];
 				m_rfLICH.getLinkSetup(setup);
@@ -332,7 +332,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		rfData[1U] = 0x00U;
 
 		// Generate the sync
-		CSync::addM17DataSync(rfData + 2U);
+		CSync::addM17StreamSync(rfData + 2U);
 
 		unsigned char lich[M17_LICH_FRAGMENT_LENGTH_BYTES];
 		m_netLICH.getFragment(lich, m_rfLICHn);
@@ -541,7 +541,7 @@ void CM17Control::writeNetwork()
 		start[1U] = 0x00U;
 
 		// Generate the sync
-		CSync::addM17HeaderSync(start + 2U);
+		CSync::addM17LinkSetupSync(start + 2U);
 
 		unsigned char setup[M17_LICH_LENGTH_BYTES];
 		m_netLICH.getLinkSetup(setup);
@@ -563,7 +563,7 @@ void CM17Control::writeNetwork()
 	data[1U] = 0x00U;
 
 	// Generate the sync
-	CSync::addM17DataSync(data + 2U);
+	CSync::addM17StreamSync(data + 2U);
 
 	m_netFrames++;
 
diff --git a/M17Defines.h b/M17Defines.h
index 5129d9a..2eae167 100644
--- a/M17Defines.h
+++ b/M17Defines.h
@@ -24,8 +24,9 @@ const unsigned int M17_RADIO_SYMBOL_LENGTH = 5U;      // At 24 kHz sample rate
 const unsigned int M17_FRAME_LENGTH_BITS    = 384U;
 const unsigned int M17_FRAME_LENGTH_BYTES   = M17_FRAME_LENGTH_BITS / 8U;
 
-const unsigned char M17_HEADER_SYNC_BYTES[] = {0x5DU, 0xDDU};
-const unsigned char M17_DATA_SYNC_BYTES[]   = {0xDDU, 0xDDU};
+const unsigned char M17_LINK_SETUP_SYNC_BYTES[] = {0x55U, 0xF7U};
+const unsigned char M17_STREAM_SYNC_BYTES[]     = {0xFFU, 0x5DU};
+const unsigned char M17_PACKET_SYNC_BYTES[]     = {0x75U, 0xFFU};
 
 const unsigned int  M17_SYNC_LENGTH_BITS  = 16U;
 const unsigned int  M17_SYNC_LENGTH_BYTES = M17_SYNC_LENGTH_BITS / 8U;
diff --git a/Sync.cpp b/Sync.cpp
index 3e53f64..5ec1f88 100644
--- a/Sync.cpp
+++ b/Sync.cpp
@@ -85,16 +85,23 @@ void CSync::addNXDNSync(unsigned char* data)
 		data[i] = (data[i] & ~NXDN_FSW_BYTES_MASK[i]) | NXDN_FSW_BYTES[i];
 }
 
-void CSync::addM17HeaderSync(unsigned char* data)
+void CSync::addM17LinkSetupSync(unsigned char* data)
 {
 	assert(data != NULL);
 
-	::memcpy(data, M17_HEADER_SYNC_BYTES, M17_SYNC_LENGTH_BYTES);
+	::memcpy(data, M17_LINK_SETUP_SYNC_BYTES, M17_SYNC_LENGTH_BYTES);
 }
 
-void CSync::addM17DataSync(unsigned char* data)
+void CSync::addM17StreamSync(unsigned char* data)
 {
 	assert(data != NULL);
 
-	::memcpy(data, M17_DATA_SYNC_BYTES, M17_SYNC_LENGTH_BYTES);
+	::memcpy(data, M17_STREAM_SYNC_BYTES, M17_SYNC_LENGTH_BYTES);
+}
+
+void CSync::addM17PacketSync(unsigned char* data)
+{
+	assert(data != NULL);
+
+	::memcpy(data, M17_PACKET_SYNC_BYTES, M17_SYNC_LENGTH_BYTES);
 }
diff --git a/Sync.h b/Sync.h
index 20ee2dd..2ca7818 100644
--- a/Sync.h
+++ b/Sync.h
@@ -33,8 +33,9 @@ public:
 
 	static void addNXDNSync(unsigned char* data);
 
-	static void addM17HeaderSync(unsigned char* data);
-	static void addM17DataSync(unsigned char* data);
+	static void addM17LinkSetupSync(unsigned char* data);
+	static void addM17StreamSync(unsigned char* data);
+	static void addM17PacketSync(unsigned char* data);
 
 private:
 };
diff --git a/Version.h b/Version.h
index efee250..6b0ecf4 100644
--- a/Version.h
+++ b/Version.h
@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20201215";
+const char* VERSION = "20201226";
 
 #endif