Added writeFast() cmd - fill FIFO or return 0

- WriteFast allows the FIFO buffers to be filled up before returning 0
- The current payload will be dropped, and the previous payload resent
- The user should just keep trying to send the same data if a 0 is
received

RF24.cpp

@@ -468,16 +468,14 @@ bool RF24::write( const void* buf, uint8_t len )
 
 /****************************************************************************/
 
-//For general use, the flags are not important to clear
+//For general use, the interrupt flags are not important to clear
 bool RF24::writeBlocking( const void* buf, uint8_t len )
 {
  //Block until the FIFO is NOT full.
  //Keep track of the MAX retries and set auto-retry if seeing failures
  //This way the FIFO will fill up and allow blocking until packets go through
  //The radio will auto-clear everything in the FIFO as long as CE remains high
 
- //Start Writing
- startWrite(buf,len);
 
  while ( (read_register(FIFO_STATUS) & _BV(FIFO_FULL))){ //Blocking only if FIFO is full. This will loop and block until TX is successful
 
@@ -486,9 +484,12 @@ bool RF24::writeBlocking( const void* buf, uint8_t len )
  reUseTX(); //Set re-transmit
  ce(LOW); //Re-Transfer packet
  ce(HIGH);
+ delayMicroseconds(15);
  }
 
  }
+ //Start Writing
+ startWrite(buf,len);
 
  return 1;
 }
@@ -500,6 +501,39 @@ void RF24::reUseTX(){
  csn(HIGH);
 
 }
+
+/****************************************************************************/
+
+//This is for when every bit of data is important
+bool RF24::writeFast( const void* buf, uint8_t len )
+{
+ //Block until the FIFO is NOT full.
+ //Keep track of the MAX retries and set auto-retry if seeing failures
+ //Return 0 so the user can control the retrys and set a timer or failure counter if required
+ //The radio will auto-clear everything in the FIFO as long as CE remains high
+
+
+ while ( (read_register(FIFO_STATUS) & _BV(FIFO_FULL))){ //Blocking only if FIFO is full. This will loop and block until TX is successful
+
+ if( get_status() & _BV(MAX_RT)){
+ write_register(STATUS,_BV(MAX_RT) ); //Clear max retry flag
+ reUseTX(); //Set re-transmit
+ ce(LOW); //Re-Transfer packet
+ ce(HIGH);
+ delayMicroseconds(15); //CE needs to stay high for 10us, for TX_REUSE to engage
+ return 0; //Return 0. The previous payload has been retransmitted
+ //From the user perspective, if you get a 0, just keep trying to send the same payload
+ }
+
+ }
+ //Start Writing
+ startWrite(buf,len);
+
+ return 1;
+}
+
+
+
 /****************************************************************************/
 
 //Per the documentation, we want to set PTX Mode when not listening. Then all we do is write data and set CE high

RF24.h

@@ -225,6 +225,7 @@ class RF24
  void txStandBy();
  bool writeBlocking( const void* buf, uint8_t len );
  void reUseTX();
+ bool writeFast( const void* buf, uint8_t len ); //Fills FIFO buffer, uses packet re-use function of the chip and returns 0 if packet failed and re-sent
 
  /**
  * @name Primary public interface