Simplification of the M17 receiver.

M17RX.cpp

@@ -174,9 +174,9 @@ void CM17RX::processData(q15_t sample)
       bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS,     M17_STREAM_SYNC_SYMBOLS_VALUES,     M17_STREAM_SYNC_BYTES,     MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
       bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS,     M17_PACKET_SYNC_SYMBOLS_VALUES,     M17_PACKET_SYNC_BYTES,     MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
 
-      if (ret1) m_nextState = M17RXS_LINK_SETUP;
+      if (ret1) m_state = M17RXS_LINK_SETUP;
-      if (ret2) m_nextState = M17RXS_STREAM;
+      if (ret2) m_state = M17RXS_STREAM;
-      if (ret3) m_nextState = M17RXS_PACKET;
+      if (ret3) m_state = M17RXS_PACKET;
     }
   } else {
     if (m_dataPtr >= m_minSyncPtr || m_dataPtr <= m_maxSyncPtr) {
@@ -184,9 +184,9 @@ void CM17RX::processData(q15_t sample)
       bool ret2 = correlateSync(M17_STREAM_SYNC_SYMBOLS,     M17_STREAM_SYNC_SYMBOLS_VALUES,     M17_STREAM_SYNC_BYTES,     MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
       bool ret3 = correlateSync(M17_PACKET_SYNC_SYMBOLS,     M17_PACKET_SYNC_SYMBOLS_VALUES,     M17_PACKET_SYNC_BYTES,     MAX_SYNC_SYMBOL_RUN_ERRS, MAX_SYNC_BIT_RUN_ERRS);
 
-      if (ret1) m_nextState = M17RXS_LINK_SETUP;
+      if (ret1) m_state = M17RXS_LINK_SETUP;
-      if (ret2) m_nextState = M17RXS_STREAM;
+      if (ret2) m_state = M17RXS_STREAM;
-      if (ret3) m_nextState = M17RXS_PACKET;
+      if (ret3) m_state = M17RXS_PACKET;
     }
   }
 
@@ -204,11 +204,7 @@ void CM17RX::processData(q15_t sample)
 
     calculateLevels(m_startPtr, M17_FRAME_LENGTH_SYMBOLS);
 
-    M17RX_STATE state = m_nextState;
+    switch (m_state) {
-    if (state == M17RXS_NONE)
-      state = m_state;
-
-    switch (state) {
       case M17RXS_LINK_SETUP:
         DEBUG4("M17RX: link setup sync found pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal);
         break;
@@ -243,13 +239,19 @@ void CM17RX::processData(q15_t sample)
       frame[0U]  = 0x00U;
       frame[0U] |= m_lostCount == (MAX_SYNC_FRAMES - 1U) ? 0x01U : 0x00U;
 
-      writeRSSIData(frame);
+      switch (m_state) {
+        case M17RXS_LINK_SETUP:
+          writeRSSILinkSetup(frame);
+          break;
+        case M17RXS_STREAM:
+          writeRSSIStream(frame);
+          break;
+        case M17RXS_PACKET:
+          writeRSSIPacket(frame);
+          break;
+      }
 
       m_maxCorr   = 0;
-
-      if (m_nextState != M17RXS_NONE)
-        m_state = m_nextState;
-
       m_nextState = M17RXS_NONE;
     }
   }
@@ -429,7 +431,7 @@ void CM17RX::samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint
   }
 }
 
-void CM17RX::writeRSSIHeader(uint8_t* data)
+void CM17RX::writeRSSILinkSetup(uint8_t* data)
 {
 #if defined(SEND_RSSI_DATA)
   if (m_rssiCount > 0U) {
@@ -438,19 +440,19 @@ void CM17RX::writeRSSIHeader(uint8_t* data)
     data[121U] = (rssi >> 8) & 0xFFU;
     data[122U] = (rssi >> 0) & 0xFFU;
 
-    serial.writeM17Header(data, M17_FRAME_LENGTH_BYTES + 3U);
+    serial.writeM17LinkSetup(data, M17_FRAME_LENGTH_BYTES + 3U);
   } else {
-    serial.writeM17Header(data, M17_FRAME_LENGTH_BYTES + 1U);
+    serial.writeM17LinkSetup(data, M17_FRAME_LENGTH_BYTES + 1U);
   }
 #else
-  serial.writeM17Header(data, M17_FRAME_LENGTH_BYTES + 1U);
+  serial.writeM17LinkSetup(data, M17_FRAME_LENGTH_BYTES + 1U);
 #endif
 
   m_rssiAccum = 0U;
   m_rssiCount = 0U;
 }
 
-void CM17RX::writeRSSIData(uint8_t* data)
+void CM17RX::writeRSSIStream(uint8_t* data)
 {
 #if defined(SEND_RSSI_DATA)
   if (m_rssiCount > 0U) {
@@ -459,12 +461,33 @@ void CM17RX::writeRSSIData(uint8_t* data)
     data[121U] = (rssi >> 8) & 0xFFU;
     data[122U] = (rssi >> 0) & 0xFFU;
 
-    serial.writeM17Data(data, M17_FRAME_LENGTH_BYTES + 3U);
+    serial.writeM17Stream(data, M17_FRAME_LENGTH_BYTES + 3U);
   } else {
-    serial.writeM17Data(data, M17_FRAME_LENGTH_BYTES + 1U);
+    serial.writeM17Stream(data, M17_FRAME_LENGTH_BYTES + 1U);
   }
 #else
-  serial.writeM17Data(data, M17_FRAME_LENGTH_BYTES + 1U);
+  serial.writeM17Stream(data, M17_FRAME_LENGTH_BYTES + 1U);
+#endif
+
+  m_rssiAccum = 0U;
+  m_rssiCount = 0U;
+}
+
+void CM17RX::writeRSSIPacket(uint8_t* data)
+{
+#if defined(SEND_RSSI_DATA)
+  if (m_rssiCount > 0U) {
+    uint16_t rssi = m_rssiAccum / m_rssiCount;
+
+    data[121U] = (rssi >> 8) & 0xFFU;
+    data[122U] = (rssi >> 0) & 0xFFU;
+
+    serial.writeM17Packet(data, M17_FRAME_LENGTH_BYTES + 3U);
+  } else {
+    serial.writeM17Packet(data, M17_FRAME_LENGTH_BYTES + 1U);
+  }
+#else
+  serial.writeM17Packet(data, M17_FRAME_LENGTH_BYTES + 1U);
 #endif
 
   m_rssiAccum = 0U;

M17RX.h

@@ -68,8 +68,9 @@ private:
   bool correlateSync(uint8_t syncSymbols, const int8_t* syncSymbolValues, const uint8_t* syncBytes, uint8_t maxSymbolErrs, uint8_t maxBitErrs);
   void calculateLevels(uint16_t start, uint16_t count);
   void samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset, q15_t centre, q15_t threshold);
-  void writeRSSIHeader(uint8_t* data);
+  void writeRSSILinkSetup(uint8_t* data);
-  void writeRSSIData(uint8_t* data);
+  void writeRSSIStream(uint8_t* data);
+  void writeRSSIPacket(uint8_t* data);
 };
 
 #endif

SerialPort.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2013,2015-2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2013,2015-2021 by Jonathan Naylor G4KLX
  *   Copyright (C) 2016 by Colin Durbridge G4EML
  *
  *   This program is free software; you can redistribute it and/or modify
@@ -63,9 +63,10 @@ const uint8_t MMDVM_P25_LOST     = 0x32U;
 const uint8_t MMDVM_NXDN_DATA    = 0x40U;
 const uint8_t MMDVM_NXDN_LOST    = 0x41U;
 
-const uint8_t MMDVM_M17_HEADER   = 0x45U;
+const uint8_t MMDVM_M17_LINK_SETUP = 0x45U;
-const uint8_t MMDVM_M17_DATA     = 0x46U;
+const uint8_t MMDVM_M17_STREAM     = 0x46U;
-const uint8_t MMDVM_M17_LOST     = 0x47U;
+const uint8_t MMDVM_M17_PACKET     = 0x47U;
+const uint8_t MMDVM_M17_LOST       = 0x48U;
 
 const uint8_t MMDVM_POCSAG_DATA  = 0x50U;
 
@@ -1258,7 +1259,7 @@ void CSerialPort::processMessage(uint8_t type, const uint8_t* buffer, uint16_t l
 #endif
 
 #if defined(MODE_M17)
-    case MMDVM_M17_HEADER:
+    case MMDVM_M17_LINK_SETUP:
       if (m_m17Enable) {
         if (m_modemState == STATE_IDLE || m_modemState == STATE_M17)
           err = m17TX.writeData(buffer, length);
@@ -1267,12 +1268,12 @@ void CSerialPort::processMessage(uint8_t type, const uint8_t* buffer, uint16_t l
         if (m_modemState == STATE_IDLE)
           setMode(STATE_M17);
       } else {
-        DEBUG2("Received invalid M17 header", err);
+        DEBUG2("Received invalid M17 link setup data", err);
         sendNAK(err);
       }
       break;
 
-    case MMDVM_M17_DATA:
+    case MMDVM_M17_STREAM:
       if (m_m17Enable) {
         if (m_modemState == STATE_IDLE || m_modemState == STATE_M17)
           err = m17TX.writeData(buffer, length);
@@ -1281,7 +1282,21 @@ void CSerialPort::processMessage(uint8_t type, const uint8_t* buffer, uint16_t l
         if (m_modemState == STATE_IDLE)
           setMode(STATE_M17);
       } else {
-        DEBUG2("Received invalid M17 data", err);
+        DEBUG2("Received invalid M17 stream data", err);
+        sendNAK(err);
+      }
+      break;
+
+    case MMDVM_M17_PACKET:
+      if (m_m17Enable) {
+        if (m_modemState == STATE_IDLE || m_modemState == STATE_M17)
+          err = m17TX.writeData(buffer, length);
+      }
+      if (err == 0U) {
+        if (m_modemState == STATE_IDLE)
+          setMode(STATE_M17);
+      } else {
+        DEBUG2("Received invalid M17 packet data", err);
         sendNAK(err);
       }
       break;
@@ -1636,7 +1651,7 @@ void CSerialPort::writeNXDNLost()
 #endif
 
 #if defined(MODE_M17)
-void CSerialPort::writeM17Header(const uint8_t* data, uint8_t length)
+void CSerialPort::writeM17LinkSetup(const uint8_t* data, uint8_t length)
 {
   if (m_modemState != STATE_M17 && m_modemState != STATE_IDLE)
     return;
@@ -1648,7 +1663,7 @@ void CSerialPort::writeM17Header(const uint8_t* data, uint8_t length)
 
   reply[0U] = MMDVM_FRAME_START;
   reply[1U] = 0U;
-  reply[2U] = MMDVM_M17_HEADER;
+  reply[2U] = MMDVM_M17_LINK_SETUP;
 
   uint8_t count = 3U;
   for (uint8_t i = 0U; i < length; i++, count++)
@@ -1659,7 +1674,7 @@ void CSerialPort::writeM17Header(const uint8_t* data, uint8_t length)
   writeInt(1U, reply, count);
 }
 
-void CSerialPort::writeM17Data(const uint8_t* data, uint8_t length)
+void CSerialPort::writeM17Stream(const uint8_t* data, uint8_t length)
 {
   if (m_modemState != STATE_M17 && m_modemState != STATE_IDLE)
     return;
@@ -1671,7 +1686,30 @@ void CSerialPort::writeM17Data(const uint8_t* data, uint8_t length)
 
   reply[0U] = MMDVM_FRAME_START;
   reply[1U] = 0U;
-  reply[2U] = MMDVM_M17_DATA;
+  reply[2U] = MMDVM_M17_STREAM;
+
+  uint8_t count = 3U;
+  for (uint8_t i = 0U; i < length; i++, count++)
+    reply[count] = data[i];
+
+  reply[1U] = count;
+
+  writeInt(1U, reply, count);
+}
+
+void CSerialPort::writeM17Packet(const uint8_t* data, uint8_t length)
+{
+  if (m_modemState != STATE_M17 && m_modemState != STATE_IDLE)
+    return;
+
+  if (!m_m17Enable)
+    return;
+
+  uint8_t reply[130U];
+
+  reply[0U] = MMDVM_FRAME_START;
+  reply[1U] = 0U;
+  reply[2U] = MMDVM_M17_PACKET;
 
   uint8_t count = 3U;
   for (uint8_t i = 0U; i < length; i++, count++)

SerialPort.h

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015,2016,2017,2018,2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2016,2017,2018,2020,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -65,8 +65,9 @@ public:
 #endif
 
 #if defined(MODE_M17)
-  void writeM17Header(const uint8_t* data, uint8_t length);
+  void writeM17LinkSetup(const uint8_t* data, uint8_t length);
-  void writeM17Data(const uint8_t* data, uint8_t length);
+  void writeM17Stream(const uint8_t* data, uint8_t length);
+  void writeM17Packet(const uint8_t* data, uint8_t length);
   void writeM17Lost();
 #endif