Merge pull request #64 from brunojoyal/master

Added timeout parameter to Packet and SerialTransfer class

Author: PowerBroker2

examples/uart_rx_file/uart_rx_file.ino

@@ -14,6 +14,18 @@ void setup()
   Serial1.begin(115200);
 
   myTransfer.begin(Serial1);
+
+  /*
+    Or, use the full constructor:
+            myTransfer.begin(Serial1, true, Serial, 50);
+    With the timeout parameter set to 50ms, a packet must be fully received and parsed within 50ms,
+    or it will be discarded.
+    The timeout value should depend on the baud rate and on the application.
+    Example back-of-the-envelope calculation:
+    115200bps = 14400Bps
+    One packet = 264B (max) should take max 264/11400 s = 0.02s = 20ms
+    to transfer. Include some time for parsing the packet (which depends on the frequency 
+    of whatever task is calling transfer.available()) - and 50ms does not sound unreasonable.
 }
 
 

src/Packet.cpp

@@ -23,9 +23,8 @@ void Packet::begin(const configST configs)
 	debug        = configs.debug;
 	callbacks    = configs.callbacks;
 	callbacksLen = configs.callbacksLen;
+	timeout 	 = configs.timeout;
 
-	// need to give the debug port a kick to get things working for some strange reason...
-	debugPort->println();
 }
 
 
@@ -47,8 +46,15 @@ void Packet::begin(const bool _debug, Stream& _debugPort)
 {
 	debugPort = &_debugPort;
 	debug     = _debug;
+	timeout = __UINT32_MAX__;
 }
 
+void Packet::begin(const bool _debug, Stream& _debugPort, uint32_t _timeout)
+{
+	debugPort = &_debugPort;
+	debug     = _debug;
+	timeout = _timeout;
+}
 
 /*
  uint8_t Packet::constructPacket(const uint16_t &messageLen, const uint8_t packetID)
@@ -114,16 +120,27 @@ uint8_t Packet::constructPacket(const uint16_t& messageLen, const uint8_t packet
  -------
   * uint8_t - Num bytes in RX buffer
 */
+
 uint8_t Packet::parse(uint8_t recChar, bool valid)
 {
+	bool packet_fresh = packetStart==0 || millis()-packetStart<timeout;
+	if(!packet_fresh){	//packet is stale, start over.
+				debugPort->println("STALE PACKET");
+				bytesRead = 0;
+				state     = find_start_byte;
+				packetStart=0;
+				return bytesRead;
+	}
 	if (valid)
 	{
 		switch (state)
 		{
 		case find_start_byte: /////////////////////////////////////////
 		{
-			if (recChar == START_BYTE)
+			if (recChar == START_BYTE){
 				state = find_id_byte;
+				packetStart=millis();
+				}
 			break;
 		}
 

src/Packet.h

@@ -41,6 +41,7 @@ struct configST
 	bool               debug        = true;
 	const functionPtr* callbacks    = NULL;
 	uint8_t            callbacksLen = 0;
+	uint32_t			timeout = __UINT32_MAX__;
 };
 
 
@@ -58,6 +59,7 @@ class Packet
 
 	void    begin(const configST configs);
 	void    begin(const bool _debug = true, Stream& _debugPort = Serial);
+	void    begin(const bool _debug, Stream& _debugPort, uint32_t _timeout);
 	uint8_t constructPacket(const uint16_t& messageLen, const uint8_t packetID = 0);
 	uint8_t parse(uint8_t recChar, bool valid = true);
 	uint8_t currentPacketID();
@@ -171,8 +173,8 @@ class Packet
 	uint8_t idByte          = 0;
 	uint8_t overheadByte    = 0;
 	uint8_t recOverheadByte = 0;
-
-
+	uint32_t packetStart = 0;
+	uint32_t timeout;
 	void    calcOverhead(uint8_t arr[], const uint8_t& len);
 	int16_t findLast(uint8_t arr[], const uint8_t& len);
 	void    stuffPacket(uint8_t arr[], const uint8_t& len);

src/SerialTransfer.cpp

@@ -42,6 +42,13 @@ void SerialTransfer::begin(Stream& _port, const bool _debug, Stream& _debugPort)
 	packet.begin(_debug, _debugPort);
 }
 
+void SerialTransfer::begin(Stream& _port, const bool _debug, Stream& _debugPort, uint32_t _timeout)
+{
+	port = &_port;
+	timeout = _timeout;
+	packet.begin(_debug, _debugPort, _timeout);
+}
+
 
 /*
  uint8_t SerialTransfer::sendData(const uint16_t &messageLen, const uint8_t packetID)

src/SerialTransfer.h

@@ -13,6 +13,7 @@ class SerialTransfer
 
 	void    begin(Stream& _port, const configST configs);
 	void    begin(Stream& _port, const bool _debug = true, Stream& _debugPort = Serial);
+	void    begin(Stream& _port, const bool _debug, Stream& _debugPort, uint32_t _timeout);
 	uint8_t sendData(const uint16_t& messageLen, const uint8_t packetID = 0);
 	uint8_t available();
 	bool    tick();
@@ -97,4 +98,5 @@ class SerialTransfer
 
   private: // <<---------------------------------------//private
 	Stream* port;
+	uint32_t timeout;
 };