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nRF51 interval and scan window

gdeblasio

Hi,

How can I know the value of the interval and scan window for an nRF51 dongle? Is there any way to change these values? What is the valid range for both parameters?

I'm using BLE beacons iBKS105 (based on the nrf51822 chipset from Nordic Semiconductor) and Wireshark 2.4.6

Thanks in advance!

  • 0 in reply to Edvin

    Hello Edvin,

    My initial question was how can I find out the scan interval and the scan window because I am not using any SDK. I would like to set those parameters in a simple way, that is, without programming any application: is there any application that allows me to set those parameters directly to the dongle?

    With respect to receiving too many advertising packets, I solved the problem going back to nRF51 Sniffer v1.01 + Wireshark 1.10.14 + JLink v616a instead of using Sniffer v2 + Wireshark 2.4.6 + JLink v616c. Maybe the problem is due to the beta version of the Sniffer (v2).

    Thank you very much for your support!

    G.

    Edit1: Sorry, I forgot to tell you that I set the advertising interval of the beacon to 1000ms

  • +1 in reply to gdeblasio

    Hello,

    The sniffer firmware does not use the SoftDevice, so it works a little different than when you program it. It does not use a scan interval and window like in the link that you posted. When you have selected a specific device, it will follow that device between the channel hops. 

     

    But are you sure that you see more packets when you use the v2 of the sniffer than you see on v1? I have not managed to replicate this, but the only thing I can think of is that this is due to the fact that you have several beacons in the same application. Are both of the beacons on the same nRF? Would it be possible to share the application, so that I can reproduce the sniffer issue here?

     

    Best regards,

    Edvin

  • 0 in reply to Edvin

    Hello Edvin,
    I think I understood your clarification: the Sniffer v1.01 simply scans all frames coming from the beacon and does not use a scan interval or a scan window, right?

    I am completely sure of receiving more packages with v2 than with v1: I have tried it on three computers (two laptops and a desktop) always with the same result. Although I have more beacons but I did the tests with just one (the rest of the beacons were off and there were no other Bluetooth devices on in the area). Attached you will find a .pcap file in which you will see something very strange: from frame 1 to frame 44 the time increment is completely different with respect to frame 45 onwards. Also you will see that from frame 45 onwards I receive the expected packets number, 1-3 packets per second, according to advertising interval set in the beacon (1000ms).

    7853.test.pcap

    If you need more information do not hesitate to ask me.

    Thank you very much!

    Cheers,

    G.

  • 0 in reply to gdeblasio

    What I would like to know is what beacon firmware you are using? I have tested it on my computer, and I see only 3 packets every second when I select it from the dropdown menu (Device->"the beacon I want to sniff") using v.2.

     

    Would it be possible to send the beacon firmware? The reason I ask is because I understand from your other case that you are shifting between two beacon modes? This may cause some unexpected behavior regarding the advertisement, and it would be interresting to see whether it is the beacon transmitting more than 3 packets per second, or if it is the sniffer v2 that behaves weird. Either way, we would have to reproduce it in order to find a fix.

     

    If you do not want to share the project here, you can send me (or the support engineer from your other case)  a PM.

     

    Best regards,

    Edvin

  • 0 in reply to Edvin

    Hello Edvin,

    I am using Accent Systems beacons, model iBKS105, firmware version EDSTEID V5.2016.12.13.1, Hardware version: v2.0. These are the same factory parameters that I have not changed and that I have also used with the two versions of the Sniffer + Wireshark.

    Thank you very much for your support!

    Best regards,

    Gabriel

    Edit1: I guess you already know, but just in case I have to tell you that the iBKS105 beacons are based on the Nordic Semiconductor nRF51822 chipset.

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