Transceiver52M: Separate main transmit and receive drive threads

This patch primarily addresses observed repeated overrun
conditions in embedded environments - namely ARM.

The heartbeat of the transceiver is derived from the receive
sample stream, which drives the main GSM clock. Detach the
transmit thread from the receive loop to avoid interfering with
the receive I/O, which is sensitive to overrun conditions if
pull process is interrupted.

Signed-off-by: Thomas Tsou <tom@tsou.cc>
diff --git a/Transceiver52M/Transceiver.h b/Transceiver52M/Transceiver.h
index 3175213..3e4f784 100644
--- a/Transceiver52M/Transceiver.h
+++ b/Transceiver52M/Transceiver.h
@@ -56,7 +56,8 @@
   VectorFIFO*  mTransmitFIFO;     ///< radioInterface FIFO of transmit bursts 
   VectorFIFO*  mReceiveFIFO;      ///< radioInterface FIFO of receive bursts 
 
-  Thread *mFIFOServiceLoopThread;  ///< thread to push/pull bursts into transmit/receive FIFO
+  Thread *mRxServiceLoopThread;   ///< thread to pull bursts into receive FIFO
+  Thread *mTxServiceLoopThread;   ///< thread to push bursts into transmit FIFO
   Thread *mControlServiceLoopThread;       ///< thread to process control messages from GSM core
   Thread *mTransmitPriorityQueueServiceLoopThread;///< thread to process transmit bursts from GSM core
 
@@ -191,7 +192,9 @@
   */
   bool driveTransmitPriorityQueue();
 
-  friend void *FIFOServiceLoopAdapter(Transceiver *);
+  friend void *RxServiceLoopAdapter(Transceiver *);
+
+  friend void *TxServiceLoopAdapter(Transceiver *);
 
   friend void *ControlServiceLoopAdapter(Transceiver *);
 
@@ -204,8 +207,9 @@
 
 };
 
-/** FIFO thread loop */
-void *FIFOServiceLoopAdapter(Transceiver *);
+/** Main drive threads */
+void *RxServiceLoopAdapter(Transceiver *);
+void *TxServiceLoopAdapter(Transceiver *);
 
 /** control message handler thread loop */
 void *ControlServiceLoopAdapter(Transceiver *);