Fragmented advertising in legacy mode (BLE 4.2)

Question

Hello. 
 I have a requirement to encrypt the scan response from my device. This means I will have to split my data in 4 packets to fit within the 27 byte limit. 
 Is there any way of telling if an advertisement has been sent in legacy mode? I know there are callbacks for this when using extended advertising. I have this with legacy support but the callback is never triggered when advertising in legacy mode. 
 Please let me know if you need any more information on my setup. 
 Device: nRF 52840 
 nRF Connect SDK version 2.1.0 / Zephyr.

Sigurd · Accepted Answer

Hi! 
 1) 
 To get the on_scanned callback, you need to add this flag: 
 
 BT_LE_ADV_OPT_NOTIFY_SCAN_REQ 
 
 snippet: 
 struct bt_le_adv_param param =
 BT_LE_ADV_PARAM_INIT(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_USE_NAME | BT_LE_ADV_OPT_NOTIFY_SCAN_REQ,
 BT_GAP_ADV_FAST_INT_MIN_2,
 BT_GAP_ADV_FAST_INT_MAX_2,
 NULL);

2) 
 You get the on_sent callback when either timeout occurs, or the number of advertising events specified have occurred. If both are set to 0, you don't get any callback. Advertising stops when either occurs. 
 
 https://docs.zephyrproject.org/latest/connectivity/bluetooth/api/gap.html#c.bt_le_ext_adv_cb.sent 
 
 https://docs.zephyrproject.org/latest/connectivity/bluetooth/api/gap.html#c.bt_le_ext_adv_start

BR, 
 Sigurd

Fragmented advertising in legacy mode (BLE 4.2)

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