Inquiries about Central beacon scanner

[leejh]

Hello, Nordic.

I'm currently developing multiple sensor beacons and a scanner for asset tracking (scanner app based on ble_app_uart_c)

ble_app_uart_c has  SCAN INTERVAL / SCAN WINDOWS time. But I saw that it restart the scan in a function called on_adv_report().

The app was originally intended to connect with beacons with nus_uuid, but when I deleted the call to the on_adv_report function.

I found that the beacons scanned by ble_evt_handler are no longer identified. ( In my case, I only receive advertising continuously without connection)

So, my inquiries are as follows:

1. If the on_adv_report function restarts the scan every time a beacon is detected, what does the scan interval and scan windows mean?

    If the above assumptions are wrong, what is the flow chart for the scanner?

2. I looked at on_adv_report and confirmed that filtering by uuid is possible. In 15.2.0 SDK, I know that filtering by manufacturer uuid is possible. Isn't it possible to filter by manufacturer uuid in previous version? If not, is there a reference example for filtering by manufacturer uuid?

 I will wait for your reply. Thanks.

[Hung Bui]

Hi Leejh, 

As you can find the flow chart of the scanning mechanism here: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v7.0.1/group___b_l_e___g_a_p___s_c_a_n___m_s_c___l_e_g_a_c_y.html?cp=4_5_2_1_2_1_5_14_0

From S132/S140 version 6.x, you would need to resume scanning by calling sd_ble_gap_scan_start() every time you get a adv_report event. 

The interval and scan window still applied until the packet event is sent to the application. The application should call sd_ble_gap_scan_start() as soon as possible. The softdevice when receiving sd_ble_gap_scan_start() will not restart the scanning, but just continue the scheduled scanning. The call is just to tell the softdevice that the buffer is now safe to use and it can continue to scan. 

2. I'm not aware of an option to scan by Manufacturer UUID. What we have in our nrf_ble_scan module is to scan by the service UUID, not the Manufactuerer UUID. But you can implement that on your own by handling the adv_report event.