NRF52840 SoftDevice S140 6.1

[Stefan B]

Hello,

I got a problem duringing advertising with the following scenario:

1. I advertise some data to a Scanner.
2. The Scanner answers with a Scan Request.
3. The ble event handler jumps into BLE_GAP_EVT_SCAN_REQ_REPORT
4. within this event, I  change the scan response data depending on the received peer address.

--> That  data is not sent in the scan response packet.

Obiviously I can not change the response data until the current advertising has been terminated.

Is this a bug in the Softdevice or done on perpose ?

Best regards

Stefan

PS: could you help me finding the ble timing parameters (timing between advertsinng --> scan request --> scan repsonse) within the bluetooth spec ?

[Stefan B]

Hello, I want to clarify:

1. The bluetooth spec foresees an inter frame space T_IFS of 150µs before the scan response packet must be sent.
2. Thus, it should be enought time to make some changes in the response data field ?!

Best regards

Stefan

[Simonr]

Hi Stefan

It is not possible to change the response data, as 150us is not enough time to signal this to the application. You can look at this case for some more info on the BLE_GAP_EVT_SCAN_REQ_REPORT event. If you wanted to use this as a security measurement, I'd recommend trying a whitelist approach instead where you can manage the devices your scanner allows to communicate with it.

The time between an adverrtising event and a scan request is ~160us and between request to response it is ~150us.

Best regards,

Simon