Dear Robin!
Maybe I'm wrong, but I suppose you code doesn't work.
I've found only this code:
// MultiTxAckPayload - the master or the transmitter
// works with two Arduinos as slaves
// each slave should the SimpleRxAckPayload program
// one with the adress {'R','x','A','A','A'}
// and the other with {'R','x','A','A','B'}
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
#define CE_PIN 9
#define CSN_PIN 10
const byte numSlaves = 2;
const byte slaveAddress[numSlaves][5] = {
** // each slave needs a different address**
** {'R','x','A','A','A'},**
** {'R','x','A','A','B'}**
** };**
RF24 radio(CE_PIN, CSN_PIN); // Create a Radio
//~ char dataToSend[10] = "Message 0";
char dataToSend[10] = "ToSlvN 0";
char txNum = '0';
int ackData[2] = {-1, -1}; // to hold the two values coming from the slave
bool newData = false;
unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000; // send once per second
//===============
void setup() {
** Serial.begin(9600);**
** Serial.println(F("Source File = /mnt/SGT/SGT-Prog/Arduino/ForumDemos/nRF24Tutorial/MultiTxAckPayload.ino "));**
** Serial.println("SimpleTxAckPayload Starting");**
** radio.begin();**
** radio.setDataRate( RF24_250KBPS );**
** radio.enableAckPayload();**
** radio.setRetries(3,5); // delay, count**
** // radio.openWritingPipe(slaveAddress); -- moved to loop()**
}
//=============
void loop() {
** currentMillis = millis();**
** if (currentMillis - prevMillis >= txIntervalMillis) {**
** send();**
** }**
** // showData(); -- moved into send()**
}
//================
void send() {
** // call each slave in turn**
** for (byte n = 0; n < numSlaves; n++){**
** // open the writing pipe with the address of a slave**
** radio.openWritingPipe(slaveAddress[n]);**
** // include the slave number in the message**
** dataToSend[5] = n + '0';**
** bool rslt;**
** rslt = radio.write( &dataToSend, sizeof(dataToSend) );**
** // Always use sizeof() as it gives the size as the number of bytes.**
** // For example if dataToSend was an int sizeof() would correctly return 2**
** Serial.print(" ======== For Slave ");**
** Serial.print(n);**
** Serial.println(" ========");**
** Serial.print(" Data Sent ");**
** Serial.print(dataToSend);**
** if (rslt) {**
** if ( radio.isAckPayloadAvailable() ) {**
** radio.read(&ackData, sizeof(ackData));**
** newData = true;**
** }**
** else {**
** Serial.println(" Acknowledge but no data ");**
** }**
** updateMessage();**
** }**
** else {**
** Serial.println(" Tx failed");**
** }**
** showData();**
** Serial.print("\n");**
** }**
** prevMillis = millis();**
}
//=================
void showData() {
** if (newData == true) {**
** Serial.print(" Acknowledge data ");**
** Serial.print(ackData[0]);**
** Serial.print(", ");**
** Serial.println(ackData[1]);**
** Serial.println();**
** newData = false;**
** }**
}
//================
void updateMessage() {
** // so you can see that new data is being sent**
** txNum += 1;**
** if (txNum > '9') {**
** txNum = '0';**
** }**
** dataToSend[8] = txNum;**
}
but I don't see any startListening or stopListening functions. I've tried to initialize every time writing pipe using openWritingPipe but it still doesn't work.