Discard repeated messages

src/application.cpp

@@ -227,6 +227,8 @@ bool Application::CheckMsgs() {
     while (modules::serial::Available()) {
         switch (protocol.DecodeRequest(modules::serial::ConsumeByte())) {
         case mpd::MessageCompleted:
+            // Discard any unread data
+            modules::serial::Reset();
             // process the input message
             return true;
             break;

src/hal/avr/usart.cpp

@@ -14,6 +14,16 @@ uint8_t USART::Read() {
     return c;
 }
 
+void USART::ResetReceiver()
+{
+    // Disable/Enable Receiver to discard pending bytes
+    husart->UCSRxB &= ~(1 << 4);
+    husart->UCSRxB |= (1 << 4);
+
+    // Reset circular buffer, head = tail
+    rx_buf.reset();
+}
+
 void USART::Write(uint8_t c) {
     _written = true;
     // If the buffer and the data register is empty, just write the byte

src/hal/circular_buffer.h

@@ -31,6 +31,11 @@ public:
         return ((index_t)(head - tail) % (size * 2)) == size;
     }
 
+    /// Reset the circular buffer to empty
+    inline void reset() {
+        head = tail;
+    }
+
     /// Advance the head index of the buffer.
     /// No checks are performed. full() needs to be queried beforehand.
     inline void push() {
@@ -101,6 +106,11 @@ public:
         return index.full();
     }
 
+    /// Reset the circular buffer to empty
+    inline void reset() {
+        index.reset();
+    }
+
     /// Insert an element into the buffer.
     /// Checks for empty spot for the element and does not change the buffer content
     /// in case the buffer is full.

src/hal/usart.h

@@ -44,6 +44,9 @@ public:
     /// @returns current character from the UART and extracts it from the read buffer
     uint8_t Read();
 
+    /// Discard all pending data from the receiver
+    void ResetReceiver();
+
     /// @param c character to be pushed into the TX buffer (to be sent)
     void Write(uint8_t c);
     /// @param str pointer to a string in RAM to be pushed byte-by-byte into the TX buffer (to be sent)

src/modules/serial.cpp

@@ -32,6 +32,10 @@ uint8_t ConsumeByte() {
     return hu::usart1.Read();
 }
 
+void Reset() {
+    hu::usart1.ResetReceiver();
+}
+
 } // namespace serial
 
 } // namespace modules

src/modules/serial.h

@@ -12,6 +12,8 @@ bool Available();
 
 uint8_t ConsumeByte();
 
+void Reset();
+
 } // namespace serial
 
 } // namespace modules