ESB on nRF52 SDK11: not sending ACK payloads

RE: ESB on nRF52 SDK11: not sending ACK payloads

Einar Thorsrud — Tue, 05 Mar 2019 18:37:28 GMT

The 15.3 release of the nRF5 SDK was limited in scope, so unfortunately this is among the several things that was not prioritized.

RE: ESB on nRF52 SDK11: not sending ACK payloads

mthomas — Tue, 05 Mar 2019 16:11:54 GMT

Any reason why this isn't fixed in SDK 15.3.0 yet?

RE: ESB on nRF52 SDK11: not sending ACK payloads

m.wagner — Mon, 04 Feb 2019 10:19:42 GMT

Well, I just made a buffer for each pipe which holds the ACK-Payload for the respective pipe, and created two additional functions to access this buffer externally.

uint32_t nrf_esb_preload_ack(uint8_t pipe, const uint8_t *p_data, uint8_t len);
uint32_t nrf_esb_flush_ack(uint8_t pipe)

Last but not least, I had to modify on_radio_disabled_rx to use my ACK-payload buffer instead of the original FIFO. Unfortunately, I can't share this code as I had to do a tonne of additional modifications to the ESB-library for it to properly work in my scenario-

RE: ESB on nRF52 SDK11: not sending ACK payloads

Einar Thorsrud — Mon, 04 Feb 2019 08:25:29 GMT

Hi,

I do not have any more information that what is in this thread. The suggested fix by ECEJeff is valid and can be used with later SDKs.

This has not yet been fixed in the SDK, as it slipped through the system because of a mishap on my part. I have bumped it again so that it can hopefully be fixed in a future release.

RE: ESB on nRF52 SDK11: not sending ACK payloads

Jose Xavier — Sun, 03 Feb 2019 23:12:32 GMT

Can you clarify in what case this bug occurs?

RE: ESB on nRF52 SDK11: not sending ACK payloads

Jose Xavier — Sun, 03 Feb 2019 23:09:50 GMT

Would you mind to share how had you done that?

RE: ESB on nRF52 SDK11: not sending ACK payloads

Einar Thorsrud — Mon, 05 Feb 2018 09:40:33 GMT

You are absolutely right that this is a bug in the ESB library. Unfortunately, it has not been fixed in the SDK yet, but I will bump this issue internally.

Your modifications seem valid, and can hopefully be useful for others until the SDK incorporates a fix.

RE: ESB on nRF52 SDK11: not sending ACK payloads

ECEJeff — Wed, 29 Nov 2017 20:27:38 GMT

Just experienced this myself today. Looks like the ESB library has a bug.

Here's how I solved the issue: I changed the following code (starting line 773 nrf_esb.c in SDK 14.1.0):

        case NRF_ESB_PROTOCOL_ESB_DPL:
            {
                if (m_tx_fifo.count > 0 &&
                    (m_tx_fifo.p_payload[m_tx_fifo.exit_point]->pipe == NRF_RADIO->RXMATCH)
                   )
                {
                    // Pipe stays in ACK with payload until TX FIFO is empty
                    // Do not report TX success on first ack payload or retransmit
                    if (p_pipe_info->ack_payload == true && !retransmit_payload)
                    {
                        if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
                        {
                            m_tx_fifo.exit_point = 0;
                        }

                        m_tx_fifo.count--;

                        // ACK payloads also require TX_DS
                        // (page 40 of the 'nRF24LE1_Product_Specification_rev1_6.pdf').
                        m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
                    }

                    p_pipe_info->ack_payload = true;

                    mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];

                    update_rf_payload_format(mp_current_payload->length);
                    m_tx_payload_buffer[0] = mp_current_payload->length;
                    memcpy(&m_tx_payload_buffer[2],
                           mp_current_payload->data,
                           mp_current_payload->length);
                }
                else
                {
                    p_pipe_info->ack_payload = false;
                    update_rf_payload_format(0);
                    m_tx_payload_buffer[0] = 0;
                }

                m_tx_payload_buffer[1] = m_rx_payload_buffer[1];
            }
            break;

to the following:

        case NRF_ESB_PROTOCOL_ESB_DPL:
            {
            	// Pipe stays in ACK with payload until TX FIFO is empty
				// Do not report TX success on first ack payload or retransmit
				if (p_pipe_info->ack_payload == true && !retransmit_payload)
				{
					if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
					{
						m_tx_fifo.exit_point = 0;
					}

					m_tx_fifo.count--;

					// ACK payloads also require TX_DS
					// (page 40 of the 'nRF24LE1_Product_Specification_rev1_6.pdf').
					m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
				}

                if (m_tx_fifo.count > 0 &&
                    (m_tx_fifo.p_payload[m_tx_fifo.exit_point]->pipe == NRF_RADIO->RXMATCH)
                   )
                {
                    p_pipe_info->ack_payload = true;

                    mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];

                    update_rf_payload_format(mp_current_payload->length);
                    m_tx_payload_buffer[0] = mp_current_payload->length;
                    memcpy(&m_tx_payload_buffer[2],
                           mp_current_payload->data,
                           mp_current_payload->length);
                }
                else
                {
                    p_pipe_info->ack_payload = false;
                    update_rf_payload_format(0);
                    m_tx_payload_buffer[0] = 0;
                }

                m_tx_payload_buffer[1] = m_rx_payload_buffer[1];
            }
            break;

This moves the completion code outside of the check for new packets to send. The SDK's code would send uninitialized data from the FIFO, which usually worked, but sometimes failed disastrously.

It's a pretty serious bug that in practice makes PRX ACK payloads unusable. Hopefully someone from Nordic will see this post and incorporate the fix into the next SDK release.

RE: ESB on nRF52 SDK11: not sending ACK payloads

Einar Thorsrud — Fri, 23 Sep 2016 05:39:27 GMT

Thanks for reporting this issue. I have forwarded it internally in Nordic, so that hopefully it can be fixed in a future SDK release.

RE: ESB on nRF52 SDK11: not sending ACK payloads

m.wagner — Thu, 22 Sep 2016 06:37:19 GMT

I modified the ESB driver to not use a FIFO in my use case. Instead, I preload one payload per pipe which keeps being sent as an ack payload (even on retransmissions) as long as it is not replaced or explicitly cleared.

RE: ESB on nRF52 SDK11: not sending ACK payloads

Einar Thorsrud — Thu, 22 Sep 2016 05:48:43 GMT

Have you had any progress on this issue? It seems like a problem in the case where you flush the TX FIFO and use ACK payload, which is something I don't think we have tested.