From 77cf9ec5a45c38b237d5a521e795b702cb06620d Mon Sep 17 00:00:00 2001
From: FesterBesterTester <git@candoran.com>
Date: Sun, 25 May 2014 01:02:19 -0400
Subject: [PATCH] RF24::available() should report, but not change, data
 availability.

---
 RF24.cpp | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/RF24.cpp b/RF24.cpp
index 9471583d..e8fe43a4 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -549,26 +549,13 @@ bool RF24::available(uint8_t* pipe_num)
   // Too noisy, enable if you really want lots o data!!
   //IF_SERIAL_DEBUG(print_status(status));
 
-  bool result = ( status & _BV(RX_DR) );
+  bool result = !(read_register(FIFO_STATUS) & _BV(RX_EMPTY));
 
   if (result)
   {
     // If the caller wants the pipe number, include that
     if ( pipe_num )
       *pipe_num = ( status >> RX_P_NO ) & B111;
-
-    // Clear the status bit
-
-    // ??? Should this REALLY be cleared now?  Or wait until we
-    // actually READ the payload?
-
-    write_register(STATUS,_BV(RX_DR) );
-
-    // Handle ack payload receipt
-    if ( status & _BV(TX_DS) )
-    {
-      write_register(STATUS,_BV(TX_DS));
-    }
   }
 
   return result;
@@ -578,9 +565,21 @@ bool RF24::available(uint8_t* pipe_num)
 
 bool RF24::read( void* buf, uint8_t len )
 {
+  uint8_t status = get_status();
+
   // Fetch the payload
   read_payload( buf, len );
 
+  // Clear the status bit
+
+  write_register(STATUS,_BV(RX_DR));
+
+  // Handle ack payload receipt
+  if ( status & _BV(TX_DS) )
+  {
+    write_register(STATUS,_BV(TX_DS));
+  }
+
   // was this the last of the data available?
   return read_register(FIFO_STATUS) & _BV(RX_EMPTY);
 }