Made public the M17Modulator.stop() function, added macro to enable the transmission of an M17 EOT frame (disabled by default).

meson.build

@@ -18,6 +18,14 @@ def = {}
 def += {'FONT_UBUNTU_REGULAR': ''}
 # def += {'FONT_FREE_SANS': ''}
 
+##
+## Firmware configuration parameters
+##
+
+# Send an M17 EOT frame at the end of transmission
+#def += {'M17_ENABLE_EOT' : ''}
+
+
 ##
 ## ----------------- Platform-independent source files -------------------------
 ##

openrtx/include/protocols/M17/M17Modulator.hpp

@@ -75,7 +75,14 @@ public:
      * @param isLast: flag signalling that current block is the last one being
      * transmitted.
      */
-    void send(const frame_t& frame, const bool isLast);
+    void send(const frame_t& frame);
+
+    /**
+     * Terminate baseband transmission.
+     * If the macro M17_ENABLE_EOT is defined an EOT frame is sent before
+     * terminating the transmission.
+     */
+    void stop();
 
 private:
 
@@ -89,9 +96,6 @@ private:
      */
     void sendBaseband();
 
-    /** Gracefully end the transmission **/
-    void stop();
-
     static constexpr size_t M17_TX_SAMPLE_RATE     = 48000;
     static constexpr size_t M17_SAMPLES_PER_SYMBOL = M17_TX_SAMPLE_RATE / M17_SYMBOL_RATE;
     static constexpr size_t M17_FRAME_SAMPLES      = M17_FRAME_SYMBOLS * M17_SAMPLES_PER_SYMBOL;

openrtx/src/protocols/M17/M17Modulator.cpp

@@ -71,7 +71,7 @@ void M17Modulator::terminate()
     baseband_buffer.reset();
 }
 
-void M17::M17Modulator::start()
+void M17Modulator::start()
 {
     if(txRunning) return;
 
@@ -102,7 +102,7 @@ void M17::M17Modulator::start()
 }
 
 
-void M17Modulator::send(const frame_t& frame, const bool isLast)
+void M17Modulator::send(const frame_t& frame)
 {
     auto it = symbols.begin();
     for(size_t i = 0; i < frame.size(); i++)
@@ -113,9 +113,6 @@ void M17Modulator::send(const frame_t& frame, const bool isLast)
 
     symbolsToBaseband();
     sendBaseband();
-
-    // If last frame, signal stop of transmission
-    if(isLast) stop();
 }
 
 void M17Modulator::stop()
@@ -123,6 +120,7 @@ void M17Modulator::stop()
     if(txRunning == false)
         return;
 
+    #ifdef M17_ENABLE_EOT
     frame_t eotFrame;
     // Fill EOT frame with 0x55, 0x5D as per M17 spec.
     for(size_t i = 0; i < eotFrame.size(); i += 2)
@@ -141,6 +139,7 @@ void M17Modulator::stop()
 
     symbolsToBaseband();
     sendBaseband();
+    #endif
 
     outputStream_stop(outStream);
     outputStream_sync(outStream, false);

openrtx/src/rtx/OpMode_M17.cpp

@@ -219,7 +219,7 @@ void OpMode_M17::txState(rtxStatus_t *const status)
         radio_enableTx();
 
         modulator.start();
-        modulator.send(m17Frame, false);
+        modulator.send(m17Frame);
     }
 
     payload_t dataFrame;
@@ -237,5 +237,8 @@ void OpMode_M17::txState(rtxStatus_t *const status)
     }
 
     encoder.encodeStreamFrame(dataFrame, m17Frame, lastFrame);
-    modulator.send(m17Frame, lastFrame);
+    modulator.send(m17Frame);
+
+    if(lastFrame)
+        modulator.stop();
 }