Understanding periodic advertising using periodic_adv and periodic_sync

RE: Understanding periodic advertising using periodic_adv and periodic_sync

Menon — Mon, 13 May 2024 09:27:29 GMT

Hello,

The timeout parameter in the sync creation process might be the reason for the periodic sync getting lost. See sync_create_param.timeout = 0xaa inside the main file of the sample; this sets the timeout parameters for the advertising synchronisation process. This specifies the maximum time that can pass without successfully receiving a periodic advertising packet before the synchronisation is considered lost. So from the sample, synchronisation will be considered lost if no packets are received in 1.7 sec/1700 ms (0xaa = 170 * 10 ms). See the below threads, which discuss more on this:

https://devzone.nordicsemi.com/f/nordic-q-a/84232/more-information-about-skip-and-timeout-parameters-of-ble-5-advertising

https://devzone.nordicsemi.com/f/nordic-q-a/103167/bt_le_per_adv_sync_create-term-event-timing.

Kind Regards,

Abhijith

RE: Understanding periodic advertising using periodic_adv and periodic_sync

Abudoo99 — Mon, 06 May 2024 07:09:52 GMT

Hello, an UPDATE:

I had commented out the prints from the scan_recv() function so I was able to get a clearer picture of what is going on. I was able to edit the data sent.

I have made some changes to the periodic_adv sample as well: I am sending data continuously in an infinite loop instead of sending three packets every 10 seconds. I have also commented out the code that stops the extended advertising.

I can see that the periodic sync is getting lost at random timings. Although it is in a do-while loop so it establishes the connection again, I would like to know if this is an observed behavior with periodic advertising or is it something we can change by changing the timeout?

Here is the log from periodic_sync sample receiving packets every five seconds from periodic_adv sample:

devzone.nordicsemi.com/.../periodic_5F00_sync_5F00_log_5F00_2.txt

RE: Understanding periodic advertising using periodic_adv and periodic_sync

Abudoo99 — Sun, 05 May 2024 00:39:31 GMT

I am using SDK v2.6.0 and yes I am trying the periodic_sync example from the SDK samples.

This is the entire log for the periodic _sync sample. I am also running the periodic_adv sample when I am running the periodic_sync. I am using TeraTerm to capture the log:

devzone.nordicsemi.com/.../periodic_5F00_sync_5F00_log.txt

I can see that it says 'Found periodic advertising' and 'Periodic Sync established' which means that the code works. But I am unable to find the mfg_data[] that I sent. I would also like to know how I can use this sync to transfer data of my choice.

RE: Understanding periodic advertising using periodic_adv and periodic_sync

Menon — Fri, 03 May 2024 11:21:24 GMT

Hello,

Could you share some more details, like which SDK version you are using here? Are you trying the periodic advertising synchronisation sample from the SDK? If so, could you attach the whole log here? You can paste this using the insert tab.

Kind Regards,

Abhijith