Weird behaviour when dynamic updating connection parameters

RE: Weird behaviour when dynamic updating connection parameters

Jur — Wed, 01 Dec 2021 10:06:02 GMT

Fair enough! Thanks a lot for taking the time to look into this!

RE: Weird behaviour when dynamic updating connection parameters

Kenneth — Wed, 01 Dec 2021 08:07:45 GMT

Good to hear you have solved the issue.

A peripheral device can only request the central device to initiate a connection parameter update, so that should explain your UPDATE 1.

Typically a central device will re-connect using the previously used connection parameters yes.

Kenneth

RE: Weird behaviour when dynamic updating connection parameters

Jur — Tue, 30 Nov 2021 19:16:56 GMT

UPDATE: it seems like I needed to use

ble_conn_params_change_conn_params

instead of

sd_ble_gap_conn_param_update

!
It seems to work OK now, thanks for looking into this :)

UPDATE2:

I have one more question. ble_conn_params_change_conn_params takes a connection parameter, and when a device disconnects i would like to reset the desired connection parameters back to the original fast parameters. How would I do this without an active connection?

UPDATE3:

This seems to be the default behaviour :)

RE: Weird behaviour when dynamic updating connection parameters

Jur — Tue, 30 Nov 2021 19:03:12 GMT

Hi Kenneth,

A little change: The low power connection parameters are now applied after the central writes a certain payload to the main characteristic, instead of enabling notifications:

You can see the L2CAP package after the payload is sent. The problem is that right after the LE Connection Update Complete package, my device is sending a NEW L2CAP which requests to go back to the previous settings..

I do not understand why this is happening at all. Could this have something to do with the values passed to ble_conn_params_init ?

Here is a PCAP containing the communication.

devzone.nordicsemi.com/.../connparams2.pcap

RE: Weird behaviour when dynamic updating connection parameters

Kenneth — Tue, 30 Nov 2021 12:27:06 GMT

Can you share your sniffer log? Then I can show you how to find it.

Kenneth

RE: Weird behaviour when dynamic updating connection parameters

Jur — Tue, 30 Nov 2021 10:39:29 GMT

Hi Kenneth, Thanks for your reply! Would you happen to have any indication of how long this is supposed to take?

RE: Weird behaviour when dynamic updating connection parameters

Kenneth — Mon, 29 Nov 2021 16:28:34 GMT

Typically when agreeing on new connection parameters, these parameters will take affect some time in future (look for connection event), this is to ensure if there is packet loss/re-transmissions, that they will not loose connection due to difference in connection parameters.

Kenneth