Fix: txStandBy hang. Updated Transfer example

- txStandBy was hanging if the last of the data timed out. Now clears
the MAX_RT flag if timed out
- Finished updating example file Transfer.ino for demonstrating
half-rate transfers using the FIFO buffers

RF24.cpp

@@ -553,6 +553,10 @@ bool RF24::txStandBy(){
 		ce(LOW);
 		return 1;
 	}
+	if( get_status() & _BV(MAX_RT)){
+		write_register(STATUS,_BV(MAX_RT) );
+	return 0;
+	}
 	return 0;
 }
 

RF24.h

@@ -270,7 +270,7 @@ public:
   void stopListening(void);
 
   /**
-   * Optimization: Improved performance and reliability
+   * @note Optimization: Improved performance and reliability
    * Write to the open writing pipe
    *
    * Be sure to call openWritingPipe() first to set the destination
@@ -293,16 +293,17 @@ public:
   bool write( const void* buf, uint8_t len );
 
   /**
-   * Optimization: New Command
+   * @note Optimization: New Command
    * Write to the open writing pipe filling up the FIFO buffers
    *
    * Be sure to call openWritingPipe() first to set the destination
    * of where to write to.
    *
    * This will not block until the 3 FIFO buffers are filled with data.
-   * Once the FIFOs are full, writeFast will simply return 0. From a user
-   * perspective, just keep trying to send the same data. The library will
-   * keep auto retrying the previous payload using the built in functionality.
+   * Once the FIFOs are full, writeFast will simply wait for success or
+   * timeout, and return 1 or 0 respectively. From a user perspective, just
+   * keep trying to send the same data. The library will keep auto retrying
+   * the current payload using the built in functionality.
    *
    * The maximum size of data written is the fixed payload size, see
    * getPayloadSize().  However, you can write less, and the remainder
@@ -317,7 +318,7 @@ public:
   bool writeFast( const void* buf, uint8_t len );
 
     /**
-     * Optimization: New Command
+     * @note Optimization: New Command
      * Write to the open writing pipe
      *
      * Be sure to call openWritingPipe() first to set the destination
@@ -344,7 +345,7 @@ public:
   bool writeBlocking( const void* buf, uint8_t len );
 
   /**
-   * Optimization: New Command
+   * @note Optimization: New Command
    * This function should be called as soon as transmission is finished to
    * drop the radio back to STANDBY-I mode. If not issued, the radio will
    * remain in STANDBY-II mode which, per the data sheet, is not a recommended
@@ -781,8 +782,8 @@ public:
 };
 
 /**
- * @example GettingStarted.pde
- *
+ * @example GettingStarted.ino
+ * Updated: TMRh20
  * This is an example which corresponds to my "Getting Started" blog post:
  * <a style="text-align:center" href="http://maniacbug.wordpress.com/2011/11/02/getting-started-rf24/">Getting Started with nRF24L01+ on Arduino</a>.
  *
@@ -793,6 +794,17 @@ public:
  * node can then see how long the whole cycle took.
  */
 
+/**
+ * @example Transfer.ino
+ * Updated: TMRh20
+ * This example demonstrates half-rate transfer using the FIFO buffers
+ *
+ * It is an example of how to use the RF24 class.  Write this sketch to two
+ * different nodes.  Put one of the nodes into 'transmit' mode by connecting
+ * with the serial monitor and sending a 'T'.  The data transfer will begin,
+ * with the receiver displaying the payload count. (32Byte Payloads)
+ */
+
 /**
  * @example nordic_fob.pde
  *
@@ -812,7 +824,7 @@ public:
  */
 
 /**
- * @example pingpair.pde
+ * @example pingpair.ino
  *
  * This is an example of how to use the RF24 class.  Write this sketch to two
  * different nodes, connect the role_pin to ground on one.  The ping node sends

examples/Transfer/Transfer.ino

@@ -19,105 +19,92 @@ TMRh20 2014
 #include "RF24.h"
 #include "printf.h"
 
-// Hardware configuration
-// Set up nRF24L01 radio on SPI bus plus pins 9 & 10 
+/*************  USER Configuration *****************************/
+                                          // Hardware configuration
+RF24 radio(48,49);                        // Set up nRF24L01 radio on SPI bus plus pins 9 & 10 
+boolean RADIO_NO = 0;  //SET THIS TO 0 or 1 for 1st or 2nd radio
 
-RF24 radio(48,49);
+/***************************************************************/
 
-// Topology
-// Radio pipe addresses for the 2 nodes to communicate.
-const uint64_t pipes[2] = { 0xABCDABCD71LL, 0x544d52687CLL };
+const uint64_t pipes[2] = { 0xABCDABCD71LL, 0x544d52687CLL };   // Radio pipe addresses for the 2 nodes to communicate.
 
-// Role management
-// Set up role.  This sketch uses the same software for all the nodes
-// in this system.  Doing so greatly simplifies testing.  
+byte data[32];                           //Data buffer for testing data transfer speeds
 
-// The various roles supported by this sketch
-typedef enum { role_TX = 1, role_RX } role_e;
-
-// The debug-friendly names of those roles
-const char* role_friendly_name[] = { "invalid", "Ping out", "Pong back"};
-
-//Set this to determine the default role of the current running sketch
-role_e role = role_RX;
-
-//Data buffer for testing data transfer speeds
-byte data[32]; 
-
-//Counter and timer for keeping track transfer info
-unsigned long counter, rxTimer;
+unsigned long counter, rxTimer;          //Counter and timer for keeping track transfer info
 float startTime, stopTime;  
+bool TX=1,RX=0,role=0;
 
-void setup(void)
-{
+void setup(void) {
 
   Serial.begin(57600);
   printf_begin();
-  printf("\n\rRF24/examples/GettingStarted/\n\r");
-  printf("ROLE: %s\n\r",role_friendly_name[role]);
-  printf("*** PRESS 'T' to begin transmitting to the other node\n\r");
 
   radio.begin();                           // Setup and configure rf radio
   radio.setChannel(1);
   radio.setPALevel(RF24_PA_MAX);
   radio.setAutoAck(1);                     // Ensure autoACK is enabled
-  radio.setRetries(2,3);                // Optionally, increase the delay between retries & # of retries
-  //radio.disableCRC();
+  radio.setRetries(1,1);                   // Optionally, increase the delay between retries & # of retries
   radio.setCRCLength(RF24_CRC_8); 
+  
+  if(RADIO_NO){                            //Lets the two radios choose the correct pipes depending on user selection
+    radio.openWritingPipe(pipes[0]);
+    radio.openReadingPipe(1,pipes[1]);
+  }else{
     radio.openWritingPipe(pipes[1]);
     radio.openReadingPipe(1,pipes[0]);
+  }
   
   radio.startListening();                 // Start listening
   radio.printDetails();                   // Dump the configuration of the rf unit for debugging
   
+  printf("\n\rRF24/examples/Transfer Rates/\n\r");
+  printf("*** PRESS 'T' to begin transmitting to the other node\n\r");
+  
   randomSeed(analogRead(0));              //Seed for random number generation
   
   for(int i=0; i<32; i++){
      data[i] = random(255);               //Load the buffer with random data
   }
-  radio.powerUp();
+  radio.powerUp();                        //Power up the radio
 }
 
 void loop(void){
 
 
-  //TX with pre-blocking writes
-  if(role == role_TX){
+  if(role == TX){
     
     delay(1500);
     
     printf("Initiating Basic Data Transfer\n\r");
     
     
-    float cycles = 10000;
+    float cycles = 1000; //Change this to a higher or lower number. 
     
     startTime = millis();
             
-    for(int i=0; i<cycles; i++){
-      if(!radio.writeFast(&data,32)){
-        counter++;
+    for(int i=0; i<cycles; i++){        //Loop through a number of cycles
+      data[0] = i;                      //Change the first byte of the payload for identification
+      if(!radio.writeFast(&data,32)){   //Write to the FIFO buffers
+        counter++;                      //Keep count of failed payloads
       }
     }
+    
     stopTime = millis();
     
-   while(!radio.txStandBy()){ }
+    while(!radio.txStandBy()){ }         //This should be called to wait for completion and put the radio in standby mode after transmission
    
    float numBytes = cycles * 32;
    float rate = numBytes / (stopTime - startTime) / cycles;
     
-    
    printf("Transfer complete at "); Serial.print(rate); printf(" KB/s \n\r");
    printf("%d of ",counter); Serial.print(cycles); printf(" Packets Failed to Send\n\r");
    counter = 0;   
     
-
-
-
    }
   
   
   
-  if(role == role_RX){
+  if(role == RX){
      while(radio.available()){       
       radio.read(&data,32);
       counter++;
@@ -130,9 +117,7 @@ void loop(void){
      printf("Payload Count: %d \n\r", counter);
      counter = 0;
    }
-    
   }
-
   //
   // Change roles
   //
@@ -140,23 +125,17 @@ void loop(void){
   if ( Serial.available() )
   {
     char c = toupper(Serial.read());
-    if ( c == 'T' && role == role_RX )
+    if ( c == 'T' && role == RX )
     {
       printf("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK\n\r");
       radio.stopListening();
-      role = role_TX;                  // Become the primary transmitter (ping out)
-      //radio.openWritingPipe(pipes[0]);
-      //radio.openReadingPipe(1,pipes[1]);
+      role = TX;                  // Become the primary transmitter (ping out)
     }
-    else if ( c == 'R' && role == role_TX )
+    else if ( c == 'R' && role == TX )
     {
       radio.startListening();
       printf("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK\n\r");      
-      
-       role = role_RX;                // Become the primary receiver (pong back)
-       
-      //radio.openWritingPipe(pipes[1]);
-      //radio.openReadingPipe(1,pipes[0]);
+      role = RX;                // Become the primary receiver (pong back)
     }
   }
 }