NCS: Softdevice+Mesh+Ext. Advertising -> TX Power Control?

[mesh777]

Hello,

I have trouble again with TX Power control. This time using Softdevice Controller and NCS2.6.0.

Previous issue which was solved (this was using Zephyr Controller):  NCS Mesh: TX Power register value does not change when changing TX Power via HCI 

Is there a common solution to control TX Power runtime, when running Mesh + Extended Advertising and Softdevice controller?

Thanks in advance! :)

[Hieu]

Hi mesh777,

You should be able to control the TX Power following the method demonstrated in the Bluetooth: HCI Power Control sample.

Please note that the SoftDevice Controller only raise the TX Power momentarily for the radio action, and then will set it back to 0. A crude way I used to confirm things are working is to repeatedly print out the content of the TXPOWER register.

Hieu

[mesh777]

Hieu said:

Please note that the SoftDevice Controller only raise the TX Power momentarily for the radio action, and then will set it back to 0

What is the reason of such behaviour? Does it mean that TX Power needs to be reconfigured continuously or it is handled by Softdevice automatically?

The reference sample does not take into account multiple AVD sets, when EXT ADV is enabled. Maybe Conn Handle somehow can be determined to configure each set?

[Hieu]

mesh777 said:

What is the reason of such behaviour? Does it mean that TX Power needs to be reconfigured continuously or it is handled by Softdevice automatically?

The SoftDevice will handle the TX Power on its own. The Host only needs to request once.

mesh777 said:

The reference sample does not take into account multiple AVD sets, when EXT ADV is enabled. Maybe Conn Handle somehow can be determined to configure each set?

I believe that the sample take into account ADV sets as well. Notice that you can set TX Power with an advertising set handle: https://github.com/nrfconnect/sdk-zephyr/blob/v3.5.99-ncs1-1/samples/bluetooth/hci_pwr_ctrl/src/main.c#L239-L240.

[mesh777]

Is there a way to determine which handles are available? With Zephyr controller it worked 0-3 for 4 sets, but with Softdevice looks that it does not work that way. For last 3 sets I get such error: "Set Tx power err: -5 reason 0x00"

EDIT: Also I tried to print value of NRF_RADIO->TXPOWER each 200ms, it always returns 0, despite that tx power was reconfigured for 8dBm using functions from the sample project.

[Hieu]

For general legacy and extended advertising, you can use https://github.com/nrfconnect/sdk-zephyr/blob/v3.5.99-ncs1-1/include/zephyr/bluetooth/hci.h#L91-L98.

But for Mesh, there is no way to get the advertising handle, unfortunately. Sorry that we ended up at this dead end after my suggestions.

May I ask why you wish to have dynamic TX power control with mesh?