updating periodic advertising data after each advert

Question

Hi, I use periodic advertising to send live data based on readings from an accelerometer. I want to change the advertising packet after every advert to the new values. 
 My advertising interval is currently set with

struct bt_le_per_adv_param per_adv_param =
 {
 .interval_min = 80, // 100ms N * 1.25 milliseconds
 .interval_max = 100, // 125ms
 .options = BT_LE_PER_ADV_OPT_NONE,
 };

At the moment I just change the advertising data by calling bt_le_per_adv_set_data every 100ms. But this seems quite imprecise 
 Is there a way to get a callback when the advert goes out? Or to read a counter of advertisements sent? Or to stack up an array of adverts somehow? 
 I've looked in the docs and all I can find is radio notify event which isn't quite what I want. I don't think it differentiates between connection events and advertisements. 
 I've also looked through zephyr/include/zephyr/bluetooth/bluetooth.h but I couldn't find anything that looked useful 
 Is there an easy way to do this? 
 Thanks for your help. 
 -Jason

ovrebekk · Accepted Answer

Hi Jason 
 There is no way to get a callback for every sent advertisement packet unfortunately. The radio notification feature is the closest you get, and as you say this one will not differentiate between the differents types of events. 
 It's a bit odd that the timer approach would be imprecise though. You mean to say that you don't see the data change as expected? 
 Possibly it would work better if you send the periodic advertisements at a faster rate than the data gets updated. Then you have a higher chance of picking up each accelerometer update, since there is always a risk that you don't manage to receive 100% of the advertise packets on the receiving side. 
 Jason said: I assume this is only for extended adverts, not periodic adverts. 
 This one should work for periodic advertising as well. 
 First off, periodic advertising is based on extended advertising, and uses a similar principle of having a small packet sent on the primary (legacy) advertising channels that points to more data being sent on the secondary channels. 
 Secondly, the bt_le_ext API's are not limited to extended advertising only. They are a replacement of the older bt_le_adv API that can do both legacy and extended advertising. 
 Best regards Torbjørn

updating periodic advertising data after each advert

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