NRF52 - ESB - Receiving duplicate packets

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Tue, 14 Feb 2023 09:52:30 GMT

Great, thank you for the help.

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Tue, 14 Feb 2023 09:48:44 GMT

Sorry, that is not possible. If you have specific questions I can answer them, but in terms of software development you will need to use the example as starting point and develop you own project. Personally I would have considered using the first 1-2bytes as a header for the application, e.g. information about what packet this was in a sequence of x packets etc. But I don't have any example or guidance on how this can be done in specific no.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Tue, 14 Feb 2023 08:58:15 GMT

This will be tricky if I need to send a 300 bytes reply fragmented in multiple acks.

Can someone from your team write a proof of concept maybe? I am sure it will benefit the whole community.

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Tue, 14 Feb 2023 08:50:15 GMT

Hello,

I opened the example project I previously linked for Gazell, I can see that the project supports bidirectional data (see that the host call nrf_gzll_add_packet_to_tx_fifo() to add data to ACK).

I can find frmo nrf_gzll_constants.h that the max payload length is 32bytes as I suspected:
#define NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH 32 ///< Maximum allowed payload length in bytes.

So this means that if you want to send 300bytes either way, then you need to fragment the data into 32byte chunks.

Gazell was never meant for dynamic switching between host and device no.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Tue, 14 Feb 2023 07:09:25 GMT

Can you please provide some sample code for Gazell RX and TX, for sending 300 byte payload?

How about bi-directional, can I change between host and device fast enough? Any other tips?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 18:52:58 GMT

32byte payload either way should be supported as-is I believe, do not believe larger is possible no.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 16:17:17 GMT

As far as i remember, Gazell has a pretty small max payload size. Is there any code available demonstrating bidirectional communication using parge payloads?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 16:13:16 GMT

Gazell:
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/gzll_02_user_guide.html
https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/gzll_examples_device_and_host.html

PTX is called device, and PRX is called host in Gazell.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 12:42:04 GMT

Are there any protocols already written that will ensure packets arrive in the other side or do I have to write it from scratch?

i can barely find anything about esb online to be honest.

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 11:48:47 GMT

[quote user="nordicfreak"]disabling the radio too soon after tx?[/quote]

In normal radio communication in the 2.4GHz it's pretty common with packet loss due to interference from nearby wifi or other bt devices. So if you have 1ms delay, you are likley only have enough time to send 1ack, and if that one is lost then the peer will retransmit again. I suspect that when you are exiting rx mode/disabling esb that the ESB library no longer remember what the latest packet received was, so once you enter rx mode again, it will treat the received packet as a new packet, hence fowarding it to the application.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 11:07:02 GMT

As you can see in my tx function, I am blocking until NRF_ESB_EVENT_TX_SUCCESS or NRF_ESB_EVENT_TX_FAILED received.

This should take care of that right?

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 11:04:38 GMT

What do you think is the reason for the duplicates? disabling the radio too soon after tx?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 11:03:26 GMT

But I see your point, if you send data so infrequently it may make more sense to follow your approach, but have in mind that having a radio in continous rx will draw current. But if you follow your approach you must live with handling duplicates in rx.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 11:00:00 GMT

[quote user="nordicfreak"]What if data is unexpected? Should I send every 1ms some empty packet from the TX until RX has data available?[/quote]

It depends on your latency requirements really.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 10:55:35 GMT

What if data is unexpected? Should I send every 1ms some empty packet from the TX until RX has data available?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 10:54:00 GMT

[quote user="nordicfreak"]Is this not a good approach?[/quote]

No, if the PTX expect data, it can just send 1byte 0xFF dummy data to fetch the data from the PTX. This is also much better in terms of current consumption.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Mon, 13 Feb 2023 10:29:46 GMT

Yes, this I understand. However, the RX might send some data after a few minutes so appending to ack would not be feasible, that's why I keep both sides in RX mode and when they want to send I switch to TX.

Is this not a good approach?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Mon, 13 Feb 2023 10:27:23 GMT

If the PRX want to send data to the PTX, then it don't disable esb or switch to tx, it simply call nrf_esb_write_payload() while in rx mode, then the packet will be appended to the next ack going from the PRX to the PTX. So there should be no need to disable esb or switch mode of operation to use nrf_esb_write_payload().

If you look at the \examples\proprietary_rf\esb_low_power_prx you can see what I mean.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Thu, 09 Feb 2023 15:56:32 GMT

even when switching to tx mode?

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Thu, 09 Feb 2023 15:55:12 GMT

Try to remove that, keep rx allways on. Or at least remove the ESB disable/enable part. When you disable/enable ESB you like also remove the info of the last received packet info, thereby it think it is a new packet.

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Thu, 09 Feb 2023 14:45:50 GMT

Check line 100 in RX code.

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Thu, 09 Feb 2023 13:54:45 GMT

And you are not starting and stopping rx here at any time? e.g. nrf_esb_start_rx()/nrf_esb_stop_rx().

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Thu, 09 Feb 2023 13:24:55 GMT

Is the TX also an nRF52840-DK? - Yes

Acks sometimes are received sometimes not.

This is nRF5 SDKv17.1? - yes

RE: NRF52 - ESB - Receiving duplicate packets

Kenneth — Thu, 09 Feb 2023 13:23:47 GMT

That should be good. This is nRF5 SDKv17.1?

Do I understand it correctly it's allways duplicates and that the ack is never received? It's not quite clear to me whether there is intermittently ack's or not.

Is the TX also an nRF52840-DK?

Kenneth

RE: NRF52 - ESB - Receiving duplicate packets

nordicfreak — Thu, 09 Feb 2023 13:20:48 GMT

PCA10056 - 3.0.0 2022.34