nRF24L01+ demo using ackPayload

I have tidied up (I hope) my use of ackLen and ackMessgLen in the versions in this Reply.
EDIT ... Note to self - I downloaded and tested this code successfully on 14/08/2016

There is a one packet delay in the signaling of an ack-reception.

I'm afraid I don't believe this happens with my code. The data that is sent in the acknowledgment is what I expect it to send.

Revised versions of the programs

The master program

// TrackControl - the master or the transmitter

 // http://tmrh20.github.io/RF24/

 //~ - CONNECTIONS: nRF24L01 Modules See:
 //~ http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
 //~ 1 - GND
 //~ 2 - VCC 3.3V !!! NOT 5V
 //~ 3 - CE to Arduino pin 9
 //~ 4 - CSN to Arduino pin 10
 //~ 5 - SCK to Arduino pin 13
 //~ 6 - MOSI to Arduino pin 11
 //~ 7 - MISO to Arduino pin 12
 //~ 8 - UNUSED

#include <SPI.h>
//~ #include <TMRh20nRF24L01.h>
//~ #include <TMRh20RF24.h>
#include <nRF24L01.h>
#include <RF24.h>


#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type
// These are the IDs of each of the slaves
const uint64_t slaveID[2] = {0xE8E8F0F0E1LL, 0xE8E8F0F0E2LL} ;

RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

int dataToSend[2];

unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000;
int txVal = 0;
int ackMessg[6];
byte ackMessgLen = 4; // NB this 4 is the number of bytes in the 2 ints that will be recieved


void setup() {

    Serial.begin(9600);
    Serial.println("Track Control Starting");
    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.enableAckPayload();
    radio.setRetries(3,5); // delay, count
}

//====================

void loop() {

    currentMillis = millis();
    if (currentMillis - prevMillis >= txIntervalMillis) {

    radio.openWritingPipe(slaveID[0]); // calls the first slave
                                        // there could be a FOR loop to call several slaves in turn
    dataToSend[0] = txVal; // this gets incremented so you can see that new data is being sent
    txVal += 1;
    dataToSend[1] = txVal;
    txVal += 1;
    bool rslt;
    rslt = radio.write( dataToSend, sizeof(dataToSend) );
    Serial.print("\nRSLT (1 = success) ");
    Serial.println(rslt);
    Serial.print("Data Sent ");
    Serial.print(dataToSend[0]);
    Serial.print("  ");
    Serial.println(dataToSend[1]);
    if ( radio.isAckPayloadAvailable() ) {
        radio.read(ackMessg,ackMessgLen);
        Serial.print("Acknowledge received: ");
        Serial.print(ackMessg[0]);
        Serial.print("  ");
        Serial.println(ackMessg[1]);
    }
    prevMillis = millis();
 }
}

and the slave program

// HandController - the slave or the receiver

    // http://tmrh20.github.io/RF24/

    //~ - CONNECTIONS: nRF24L01 Modules See:
    //~ http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo
    //~ 1 - GND
    //~ 2 - VCC 3.3V !!! NOT 5V
    //~ 3 - CE to Arduino pin 9
    //~ 4 - CSN to Arduino pin 10
    //~ 5 - SCK to Arduino pin 13
    //~ 6 - MOSI to Arduino pin 11
    //~ 7 - MISO to Arduino pin 12
    //~ 8 - UNUSED

#include <SPI.h>
//~ #include <TMRh20nRF24L01.h>
//~ #include <TMRh20RF24.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

// NOTE: the "LL" at the end of the constant is "LongLong" type

const uint64_t   deviceID = 0xE8E8F0F0E1LL; // Define the ID for this slave

int valChange = 1;

RF24 radio(CE_PIN, CSN_PIN);

int dataReceived[2];
int ackData[2] = {12,23};

void setup() {

    Serial.begin(9600);
    delay(1000);
    Serial.println("Hand Controller Starting");
    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.openReadingPipe(1,deviceID);
    radio.enableAckPayload();
    radio.writeAckPayload(1, ackData, sizeof(ackData));
    radio.startListening();
}

void loop() {

    if ( radio.available() ) {
        radio.read( dataReceived, sizeof(dataReceived) );
        Serial.print("Data received Number0 ");
        Serial.print(dataReceived[0]);
        Serial.print(" Number1 ");
        Serial.println(dataReceived[1]);
        radio.writeAckPayload(1, ackData, sizeof(ackData));
        ackData[0] += valChange; // this just increments so you can see that new data is being sent
    }
}

NOTE that these programs use TMRh20's version of the RF24 library

...R

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