Created a non-blocking write and an example for how to use it.

RF24.cpp

@@ -356,17 +356,8 @@ boolean RF24::write( const void* buf, uint8_t len )
 {
   boolean result = false;
 
-  // Transmitter power-up
-  write_register(CONFIG, ( read_register(CONFIG) | _BV(PWR_UP) ) & ~_BV(PRIM_RX) );
-  delay(2);
-
-  // Send the payload
-  write_payload( buf, len );
-
-  // Allons!
-  ce(HIGH);
-  delayMicroseconds(15);
-  ce(LOW);
+  // Begin the write
+  startWrite(buf,len);
 
   // ------------
   // At this point we could return from a non-blocking write, and then call
@@ -379,7 +370,7 @@ boolean RF24::write( const void* buf, uint8_t len )
   uint8_t observe_tx;
   uint8_t status;
   uint32_t sent_at = millis();
-  const uint32_t timeout = 100; //ms to wait for timeout  
+  const uint32_t timeout = 500; //ms to wait for timeout  
   do
   {
     status = read_register(OBSERVE_TX,&observe_tx,1);
@@ -420,6 +411,22 @@ boolean RF24::write( const void* buf, uint8_t len )
 
   return result;
 }
+/******************************************************************/
+
+void RF24::startWrite( const void* buf, uint8_t len )
+{
+  // Transmitter power-up
+  write_register(CONFIG, ( read_register(CONFIG) | _BV(PWR_UP) ) & ~_BV(PRIM_RX) );
+  delay(2);
+
+  // Send the payload
+  write_payload( buf, len );
+
+  // Allons!
+  ce(HIGH);
+  delayMicroseconds(15);
+  ce(LOW);
+}
 
 /******************************************************************/
 
@@ -507,6 +514,8 @@ void RF24::whatHappened(bool& tx_ok,bool& tx_fail,bool& rx_ready)
   tx_ok = status & _BV(TX_DS);
   tx_fail = status & _BV(MAX_RT);
   rx_ready = status & _BV(RX_DR);
+
+  //print_status(status);
 }
 
 /******************************************************************/

RF24.h

@@ -252,9 +252,6 @@ public:
      * getPayloadSize().  However, you can write less, and the remainder
      * will just be filled with zeroes.
      *
-     * @todo Write a non-blocking write to support users who want to 
-     * check on progress separately or use an interrupt.
-     *
      * @param buf Pointer to the data to be sent
      * @param len Number of bytes to be sent
      * @return True if the payload was delivered successfully false if not
@@ -403,6 +400,21 @@ public:
      */
     boolean available(uint8_t* pipe_num);
 
+    /**
+     * Non-blocking write to the open writing pipe
+     *
+     * Just like write(), but it returns immediately. To find out what happened
+     * to the send, catch the IRQ and then call whatHappened().
+     *
+     * @see write()
+     * @see whatHappened()
+     *
+     * @param buf Pointer to the data to be sent
+     * @param len Number of bytes to be sent
+     * @return True if the payload was delivered successfully false if not
+     */
+    void startWrite( const void* buf, uint8_t len );
+
     /**
      * Enable custom payloads on the acknowledge packets
      *

examples/pingpair_irq/pingpair_irq.pde

@@ -7,12 +7,10 @@
  */
 
 /**
- * Example of using Ack Payloads
+ * Example of using interrupts
  *
- * This is an example of how to do two-way communication without changing 
- * transmit/receive modes.  Here, a payload is set to the transmitter within 
- * the Ack packet of each transmission.  Note that the payload is set BEFORE
- * the sender's message arrives.
+ * This is an example of how to user interrupts to interact with the radio.
+ * It builds on the pingpair_pl example, and uses ack payloads.
  */
  
 #include <SPI.h>
@@ -58,6 +56,13 @@ const char* role_friendly_name[] = { "invalid", "Sender", "Receiver"};
 // The role of the current running sketch
 role_e role;
 
+// Message buffer to allow interrupt handler to print messages
+bool message_ready;
+char message[100];
+
+// Interrupt handler, check the radio because we got an IRQ
+void check_radio(void);
+
 void setup(void)
 {
   //
@@ -81,9 +86,15 @@ void setup(void)
   
   Serial.begin(57600);
   printf_begin();
-  printf("\n\rRF24/examples/pingpair_pl/\n\r");
+  printf("\n\rRF24/examples/pingpair_irq/\n\r");
   printf("ROLE: %s\n\r",role_friendly_name[role]);
 
+  //
+  // Attach interrupt handler to interrupt #0 (using pin 2)
+  //
+
+  attachInterrupt(0, check_radio, FALLING);
+
   //
   // Setup and configure rf radio
   //
@@ -93,6 +104,9 @@ void setup(void)
   // We will be using the Ack Payload feature, so please enable it
   radio.enableAckPayload();
 
+  // Pick a high channel
+  radio.setChannel(110);
+
   //
   // Open pipes to other nodes for communication
   //
@@ -123,9 +137,10 @@ void setup(void)
   radio.printDetails();
 }
 
+static uint32_t message_count = 0;
+
 void loop(void)
 {
-  static uint32_t message_count = 0;
   
   //
   // Sender role.  Repeatedly send the current time
@@ -133,17 +148,10 @@ void loop(void)
   
   if (role == role_sender)
   {
-    // Take the time, and send it.  This will block until complete
+    // Take the time, and send it.
     unsigned long time = millis();
     printf("Now sending %lu...",time);
-    radio.write( &time, sizeof(unsigned long) );
-
-    if ( radio.isAckPayloadAvailable() )
-    {
-      radio.read(&message_count,sizeof(message_count));
-      printf("Ack: [%lu] ",message_count);
-    } 
-    printf("OK\n\r");
+    radio.startWrite( &time, sizeof(unsigned long) );
     
     // Try again soon 
     delay(2000);
@@ -176,5 +184,47 @@ void loop(void)
       ++message_count;
     }
   }
+
+  //
+  // Message handler.  Display messages from the interrupt
+  //
+  if ( message_ready )
+  {
+    message_ready = false;
+    Serial.println(message);
+  }
 }
+
+void check_radio(void)
+{
+  // What happened?
+  bool tx,fail,rx;
+  radio.whatHappened(tx,fail,rx);
+ 
+  char *messageptr = message;
+  message_ready = true;
+  sprintf(message,"Unknown");
+  
+  if ( tx )
+  {
+    radio.powerDown();
+    sprintf(messageptr,"Send:OK ");
+    messageptr += strlen(messageptr);
+  }
+
+  if ( fail )
+  {
+    radio.powerDown();
+    sprintf(messageptr,"Send:Failed ");
+    messageptr += strlen(messageptr);
+  }
+
+  if ( rx )
+  {
+    radio.read(&message_count,sizeof(message_count));
+    sprintf(messageptr,"Ack:%lu ",message_count);
+    messageptr += strlen(messageptr);
+  }
+}
+
 // vim:ai:cin:sts=2 sw=2 ft=cpp