Connection dropped immediately by peripheral while connecting from nRF52840

RE: Connection dropped immediately by peripheral while connecting from nRF52840

Einar Thorsrud — Mon, 05 Dec 2022 07:43:11 GMT

I see, that is good. The next then would probably be to check what the difference is with regards to what you see on air between the nRF Connect SDK central examples and the others to help narrow down what it could be that the peripheral requires. I do not have any more specific advice, unfortunately.

RE: Connection dropped immediately by peripheral while connecting from nRF52840

DFisch — Thu, 01 Dec 2022 17:05:38 GMT

After spending several hours of analyzing, setting up toolchains and troubleshooting, I found a working setup.

Not working:

nRF5 SDK central examples
nRF Connect Desktop (probably also based on nRF5 SDK / SoftDevice)
NimBLE open-source bluetooth stack

Working:

nRF Connect SDK central examples

RE: Connection dropped immediately by peripheral while connecting from nRF52840

DFisch — Thu, 01 Dec 2022 14:23:28 GMT

Hi,

Thanks for your reply. Unfortunately, the peripheral is not our product.

I tried to compare all traces for working/non-working centrals and try to adjust nRF52840 parameters to eliminate all differences.

What I did so far:

PHY Flag set to 1M in packet header
CSA set to #1 in CONNECT_IND header
Window Size: 2 (2,5 msec)
Window Offset: 35 (43,75 msec)
Interval: 40 (50 msec)
Latency: 0
Timeout: 500 (5000 msec)
Sleep clock accuracy: 1 (151ppm to 250ppm)
Adjust the feature map in LL_FEATURE_REQ

Attached the wireshark log for nRF52840 central with all parameters adjusted to be the same like in successfull Android 9 connection procedure.

I'm running out of ideas what else could cause the peripheral to just terminate the connection. Android 9, 11 and Windows central will work just fine.

As there is same behavior with nRFConnect Desktop app and also for DK and Dongle, it seems to be some general issue. What else could cause differences, that are maybe hidden by the sniffing tool?
Any more timing settings that can be adjusted?

Regards

wireshark.png

nRF52840_params.pcapng

Android9_params.pcapng

RE: Connection dropped immediately by peripheral while connecting from nRF52840

Einar Thorsrud — Thu, 01 Dec 2022 12:21:24 GMT

Hi,

The disconnect reason in nRF5280_DK.pcapng is 0x13 (Remote user terminated connection), so the peripheral decided to do terminate for some reason which we cannot see from the sniffer trace. If you have developed the peripheral then the simplest would probably be to debug on the peripheral end to see what happens there and why it disconnects. If that is not your product, you don't really have any other way than to try to compare traces to see the difference in the central behavior, and experiment