Smallest amount of advertising time?

[Elm]

Hi,

I would like to misuse the SDK by creating an communications systems based on advertising. From several Q&A posts, e.g. this one), I understand that the current S130 softdevice (1.0.0) does not support simultaneous advertising and scanning. If I understand that post correctly, it suggests using:

  ble_gap_adv_start(), 
  ble_gap_adv_stop(), 
  sd_ble_gap_scan_start() and
  sd_ble_gap_scan_stop()

to control the advertising.

Now, how do I create the minimum advertising/non-scanning time? I would like to send exactly one BLE Advertisement Event (i.e one advertisement on each of the three advertisement channels.)

Could I do like this: After a ble_gap_adv_start(), start a timer, set to maybe 20ms, after which I call ble_gap_adv_stop()?

Or, is there any Softdevice event that I can use to catch when the BLE Advertising Event is over?

any help appreciated.

regards, Elm

[shibshab]

You can use the radio notifications in order to get notified once the radio has gone from disabled to enabled back to disabled state. The SDK module "ble_radio_notifications.c" provides simplified functionality for this.

static void my_radio_event_handler(bool radio_active) { ... }

...
    err_code = ble_radio_notification_init(NRF_APP_PRIORITY_HIGH,
                                       NRF_RADIO_NOTIFICATION_DISTANCE_800US,
                                       my_radio_event_handler);

This will then register a callback to my_radio_event_handler when the radio changes state (active/not active).

[Petter Myhre]

The conclusion of the question you linked to is not that you cannot scan and advertise at the same time. It is that you can't start to advertise if you are scanning, but you can start to scan if you are advertising. The workaround was to stop scanning, then start advertising, then start scanning again.

However, I believed this bug is fixed in S130 v1.0.0, and the version they were talking about was 0.5.0.

Anyways, the best solution to your question is the one shibshab has given you, but a timer would also probably work, since advertising would start quickly as long as you are not doing anything else, like scanning.

You will not get an event every time there is an advertising event. You will get an advertising timeout event, as you already know.

[Elm]

Unfortunately, this does not help. I cannot see what kid of radio activity (transmit or receive) created the event. Elm

[Elm]

I consider my original question out of date, but this is the best answer I got. Elm