Unable to scan advertising device after it gets bonded.

RE: Unable to scan advertising device after it gets bonded.

Hung Bui — Mon, 20 Nov 2023 10:03:55 GMT

Hi Swapnil,

I'm glad that you found the issue. You can use NRF_BLE_SCAN_EVT_NOT_FOUND, but if the filter is not needed you can just remove the filter. I don't see much point of using the filter if the name is not included in the advertising packet.
Of course if you have a reason to use it (if before bonding it advertiser with name) then it's fine.

RE: Unable to scan advertising device after it gets bonded.

Swapnil Karkare — Mon, 20 Nov 2023 07:09:21 GMT

Hi,

There is misunderstanding from my side. The advertising is unidirected one.To verify the packets I am using Name filter comparison. But actual advertising packet doesn't have Name in adv data. I can see the adv when I compare respective MAC address. That resolved my issue.

Also found out that using nrf_ble_scan. library we can see those adv packet in event NRF_BLE_SCAN_EVT_NOT_FOUND. So no need to use BLE_GAP_EVT_ADV_REPORT BLE event handler.

Thanks.

RE: Unable to scan advertising device after it gets bonded.

Hung Bui — Fri, 17 Nov 2023 13:43:31 GMT

Hi,

Please clarify what I pointed to earlier. I don't see the device doing Directed advertising, it's more likely also Undirected advertising, just with different flag.

You can do a test by setting up a device doing similar advertising with the same flag and check if the scanner can actually scan.

Please be aware that BLE_GAP_SCAN_FP_ACCEPT_ALL will scan all advertising packet, but it will not show the directed advertising with the wrong address. So there can be a chance that the directed advertising was using a wrong address.

It's important that you can verify that the device actually does directed advertising, not the normal one. And that the directed advertising packet has the correct target address.

Don't use NAME filter. The directed advertising packet doesn't have any name included in the packet, only address.

RE: Unable to scan advertising device after it gets bonded.

Swapnil Karkare — Fri, 17 Nov 2023 10:47:50 GMT

Hi Hung,

I have attached my scan init implementation. Also using BLE_GAP_SCAN_FP_ACCEPT_ALL as filter policy. I have also tried to check BLE_GAP_EVT_ADV_REPORT event. Where i can compare desire MAC address with all adv report. I Didn't found any match there as well.

Unfortunately, The Testing going on at diff location so they don't have nrf dongle or dk.

Also we are using NAME filter for scanning.

RE: Unable to scan advertising device after it gets bonded.

Hung Bui — Fri, 17 Nov 2023 10:11:27 GMT

Hi Swapnil,
From what I can see both of the screenshot showed that the advertising type was "Connectable Undirected"
So I'm not so sure if one of them was doing directed advertising.

As far as I know the Softdevice can scan regardless if the device has the discoverable flag or not.

Could you show how you do scanning ?

Could you try capture a sniffer trace when the device does advertising in discoverable and non-discoverable ?