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JBron
Associate II
December 21, 2021
Question

Any way to scan BLE devices that are non-discoverable?

  • December 21, 2021
  • 3 replies
  • 2102 views

Hi,

I know that the question may seem silly (if devices are non-discoverable they should not be reported in a BLE scan result) but it looks like it is more complicated than that.

I am using STM32WB55 MCU.

I need to scan for BLE beacons that are around my device. I already integrated many BLE beacons in my firmware.

Now I want to support another BLE beacon but this one does not set any of the LE Limited Discoverable Mode (bit 0) or LE General Discoverable Mode (bit 1) flag in its AD flags.

Currently when I call the Scan_Request function (app_ble.c) it does not report this device advertising frames (as expected I guess).

Is there a way to force such non-discoverable devices to be reported in scan results?

The BLE beacon provider (that is also my customer at the end, so complex relationship) mentioned that other BLE devices are able to scan it (and indeed some BLE applications on my smartphone does show it).

And looking on internet it is not that clear that having those 2 bits unset should result in ignoring the advertising frame (ex: https://github.com/WebBluetoothCG/web-bluetooth/issues/141)

Anyway, any help would be greatly appreciated here.

Thanks & Best Regards,

Julien.

This topic has been closed for replies.

3 replies

Remy ISSALYS
ST Technical Moderator
April 4, 2022

Hello,

In order to see non-discoverable devices, you need to recover the scan responses.

Best Regards

FrankYang-P&S
Associate II
October 11, 2022

Hi Remy,

Would you please talk about more detail about how to recover the scan responses. As I have the same issue.

Thanks a lot,

Best Regards

Frank