Merge pull request #40 from dparson55/discardData

Closes #39

examples/MultiplePacketSizes_RX/MultiplePacketSizes_RX.ino

@@ -53,24 +53,38 @@ void loop()
     // 'hasData' returns the size of the packet that was received, or 0 if there is no data.
     uint8_t packetSize = _radio.hasData();
 
-    if (packetSize == sizeof(RadioPacket1))
+    if (packetSize > 0)
     {
-        _radio.readData(&_radioData1);
+        if (packetSize == sizeof(RadioPacket1))
+        {
+            _radio.readData(&_radioData1);
 
-        Serial.print("Received ");
-        Serial.print(_radioData1.Counter);
-        Serial.print(" from radio ");
-        Serial.println(_radioData1.FromRadioId);
-    }
-    else if (packetSize == sizeof(RadioPacket2))
-    {
-        _radio.readData(&_radioData2);
+            Serial.print("Received ");
+            Serial.print(_radioData1.Counter);
+            Serial.print(" from radio ");
+            Serial.println(_radioData1.FromRadioId);
+        }
+        else if (packetSize == sizeof(RadioPacket2))
+        {
+            _radio.readData(&_radioData2);
+
+            String msg = String(_radioData2.Message);
+
+            Serial.print("Received '");
+            Serial.print(msg);
+            Serial.print("' from radio ");
+            Serial.println(_radioData2.FromRadioId);
+        }
+        else
+        {
+            // We have a packet with an unexpected size, either an invalid packet or packet
+            // that was sent from a radio that we cannot handle, so remove it from the radio.
 
-        String msg = String(_radioData2.Message);
+            Serial.print("Received packet with length '");
+            Serial.print(packetSize);
+            Serial.println("', it will be discarded");
 
-        Serial.print("Received '");
-        Serial.print(msg);
-        Serial.print("' from radio ");
-        Serial.println(_radioData2.FromRadioId);
+            _radio.discardData(packetSize);
+        }
     }
 }

library.properties

@@ -1,5 +1,5 @@
 name=NRFLite
-version=2.2.2
+version=2.3.0
 author=Dave Parson <dparson55@hotmail.com>
 maintainer=Dave Parson <dparson55@hotmail.com>
 sentence=nRF24L01+ library requiring very little code along with YouTube videos showing all available features.

src/NRFLite.cpp

@@ -88,6 +88,20 @@ void NRFLite::addAckData(void *data, uint8_t length, uint8_t removeExistingAcks)
     spiTransfer(WRITE_OPERATION, (W_ACK_PAYLOAD | 1), data, length);
 }
 
+void NRFLite::discardData(uint8_t unexpectedDataLength)
+{
+    // Read data from the RX buffer.
+    uint8_t data[unexpectedDataLength];
+    spiTransfer(READ_OPERATION, R_RX_PAYLOAD, &data, unexpectedDataLength);
+
+    // Clear data received flag.
+    uint8_t statusReg = readRegister(STATUS_NRF);
+    if (statusReg & _BV(RX_DR))
+    {
+        writeRegister(STATUS_NRF, statusReg | _BV(RX_DR));
+    }
+}
+
 uint8_t NRFLite::hasAckData()
 {
     // If we have a pipe 0 packet sitting at the top of the RX buffer, we have auto-acknowledgment data.

src/NRFLite.h

@@ -44,13 +44,15 @@ class NRFLite {
     uint8_t hasAckData();
 
     // Methods for receivers.
-    // hasData    = Checks to see if a data packet has been received and returns its length.  It also puts the radio in RX mode
-    //              if it was previously in TX mode.
-    // addAckData = Enqueues an acknowledgment data packet for sending back to a transmitter.  Whenever the transmitter sends the 
-    //              next data packet, it will get this ACK packet back in the response.  The radio will store up to 3 ACK packets
-    //              and will not enqueue more if full, so you can clear any stale packets using the 'removeExistingAcks' parameter.
+    // hasData     = Checks to see if a data packet has been received and returns its length.  It also puts the radio in RX mode
+    //               if it was previously in TX mode.
+    // addAckData  = Enqueues an acknowledgment data packet for sending back to a transmitter.  Whenever the transmitter sends the 
+    //               next data packet, it will get this ACK packet back in the response.  The radio will store up to 3 ACK packets
+    //               and will not enqueue more if full, so you can clear any stale packets using the 'removeExistingAcks' parameter.
+    // discardData = Removes the current received data packet.  Useful if a packet of an unexpected size is received.
     uint8_t hasData(uint8_t usingInterrupts = 0);
-    void addAckData(void *data, uint8_t length, uint8_t removeExistingAcks = 0); 
+    void addAckData(void *data, uint8_t length, uint8_t removeExistingAcks = 0);
+    void discardData(uint8_t unexpectedDataLength);
 
     // Methods when using the radio's IRQ pin for interrupts.
     // Note that if interrupts are used, do not use the send and hasData functions.  Instead the functions below should be used.