Advertisement interval Vs Connection interval

RE: Advertisement interval Vs Connection interval

awneil — Tue, 18 Oct 2016 06:59:01 GMT

Correct: advertising stops once connected.

RE: Advertisement interval Vs Connection interval

awneil — Tue, 18 Oct 2016 06:54:34 GMT

As far as Bluetooth is concerned, you can vary the advertising interval however & whenever you like (within the spec limits)

But if you have structured your software design with just a single, global "APP_ADV_INTERVAL" - then that's something you'll need to rethink!

RE: Advertisement interval Vs Connection interval

AmiguelS — Mon, 17 Oct 2016 23:47:13 GMT

If I'm not mistaken, the device stops advertising once it connects. If the device becomes disconnected, you have to run the advertising start procedure. If you use a variable as said above, you can change the interval at will, and the change will become effective wonce you start advertising again. I'm not 100% sure on this matter, so please correct me if I'm wrong.

RE: Advertisement interval Vs Connection interval

nordicdev — Mon, 17 Oct 2016 22:12:39 GMT

Hi Amiguel, THanks for the reply. Is it possible to change advertisement interval on the fly(while the connection is still on and not disconnected)? THanks

RE: Advertisement interval Vs Connection interval

AmiguelS — Mon, 17 Oct 2016 17:10:16 GMT

As anweil pointed out, Advertising Interval and Connection Interval are independent from each other.

If you want to force a connection to have a certain Connection Interval (CI), you should set MIN_CONN_INTERVAL and MAX_CONN_INTERVAL to the same value. But beware that not all devices support every CI. Some more information here.

As to your other question (re-connect), yes, you may choose a different Advertising Interval for each situation. In your code, there should something like:

ble_gap_adv_params_t advertising_parameters;
....
advertising_parameters.interval = APP_ADV_INTERVAL;
....
sd_ble_gap_adv_start(&advertising_parameters);

In that piece of code ADVERTISING_INTERVAL is a #define, which makes it constant. This is similar to what is provided on the Nordic examples. However, you may instead use a variable, and set it for the value that you wish, depending on the situation, using

advertising_parameters.interval = my_adv_interval;

RE: Advertisement interval Vs Connection interval

nordicdev — Mon, 17 Oct 2016 15:21:30 GMT

Hi Awneil, consider the situation phone and nRF51 have already been connected and bonded before. Then, the phone and app have been disconnected(for example, phone has gone out of range of the nRF51 Bluetooth range). Now, will the nRF51 be using advertisement packets (using advertisement interval) to make itself available on the Bluetooth network so that the app can find it and reconnect to it, or, is there any re-connection advertisement interval to do so? I am asking this because, for reconnection (example: phone has gone out of the nRF51 Bluetooth range, and when the phone comes back into the range, my nRF51 would have already started a sensitive algorithm, which needs minimal softdevice's cpu block time), I need the re-connection advertisement interval to be as slow as 1 second or more.

RE: Advertisement interval Vs Connection interval

nordicdev — Mon, 17 Oct 2016 15:08:53 GMT

Hi Awneil, Thanks for the reply. Is advertisement interval in APP_ADV_INTERVAL and connection interval in MIN_CONN_INTERVAL and MAX_CONN_INTERVAL?

RE: Advertisement interval Vs Connection interval

awneil — Mon, 17 Oct 2016 10:12:34 GMT

Yes - the Advertising Interval & Connection Interval are entirely independent.