ESB ACK packet not received?

[Philip]

Hi.

I am experimenting with using a nRF52832 to communicate with a nRF24L01+. It is almost working, the nRF52 is sending a packed to the nRF24 ok, and the NRF_ESB_EVENT_TX_SUCCESS event is triggered when the device is in range, so it must be at least detecting the ACK packet back to know the message got through ok. If I turn the nRF24 off (which is setup as RX) then the NRF_ESB_EVENT_TX_FAILED event is triggered instead.

However I am struggling to get the NRF_ESB_EVENT_RX_RECEIVED: event to trigger so I can read the ACK packet.

Basically my question is what will cause the NRF_ESB_EVENT_RX_RECEIVED event to trigger rather than the NRF_ESB_EVENT_TX_SUCCESS? Will it only be triggered when in RX mode, and not by an ACK packet. If so where would I read this ACK payload?

Thanks

void nrf_esb_event_handler(nrf_esb_evt_t const * p_event)
{
    nrf_gpio_pin_set(LED_3);
    nrf_gpio_pin_set(LED_4);
    switch (p_event->evt_id)
    {
        case NRF_ESB_EVENT_TX_SUCCESS:
            nrf_gpio_pin_clear(LED_4); //turn on LED
            
            //NRF_LOG_DEBUG("TX SUCCESS EVENT");
            break;
        case NRF_ESB_EVENT_TX_FAILED:
            nrf_gpio_pin_clear(LED_3); //turn on LED
            //NRF_LOG_DEBUG("TX FAILED EVENT");
            (void) nrf_esb_flush_tx();
            (void) nrf_esb_start_tx();
            
            break;
        case NRF_ESB_EVENT_RX_RECEIVED:
            
            //NRF_LOG_DEBUG("RX RECEIVED EVENT");
            while (nrf_esb_read_rx_payload(&rx_payload) == NRF_SUCCESS)
            {
                nrf_gpio_pin_clear(LED_2);
                if (rx_payload.length > 0)
                {
                
                    //NRF_LOG_DEBUG("RX RECEIVED PAYLOAD");
                }
            }
            break;
        
    }
    NRF_GPIO->OUTCLR = 0xFUL << 12;
    NRF_GPIO->OUTSET = (p_event->tx_attempts & 0x0F) << 12;
}

[Philip]

I have just found a few similar cases that suggest a data packed can only be received with the ACK if the protocol is NRF_ESB_PROTOCOL_ESB_DPL rather than NRF_ESB_PROTOCOL_ESB i.e. dynamic payload is on.

So does this mean a legacy nRF24L01+ system set up to use static payloads and as a RX, can't communicate back via ACK to a nRF52832 setup as a TX? 

Thanks