How to specify default TX power at runtime for the nrf5340?

RE: How to specify default TX power at runtime for the nrf5340?

Einar Thorsrud — Mon, 03 Jun 2024 10:56:42 GMT

Hi,

I am glad to hear it works. Regarding doumentation that seems to be missing, and I have asked the team to look into that.

RE: How to specify default TX power at runtime for the nrf5340?

EDLT — Fri, 31 May 2024 19:25:05 GMT

Einar, thanks for your input. I was able to test and verify the behavior. I've not seen anything like this mentioned in documentation, and think it would be great to add this kind of detail. Thanks again for your help.

RE: How to specify default TX power at runtime for the nrf5340?

Einar Thorsrud — Mon, 27 May 2024 06:45:04 GMT

The handle is ignored when the type is scan, so you can pass 0.

RE: How to specify default TX power at runtime for the nrf5340?

EDLT — Fri, 24 May 2024 16:48:37 GMT

I see, since there's no handle, what handle value should be used when constructing bt_hci_cp_vs_write_tx_power_level?

RE: How to specify default TX power at runtime for the nrf5340?

Einar Thorsrud — Fri, 24 May 2024 14:09:24 GMT

Hi,

I did not get a chance to test this now, but looking at the implementation the same shoudl apply to scanning, by using handle type BT_HCI_VS_LL_HANDLE_TYPE_SCAN.

RE: How to specify default TX power at runtime for the nrf5340?

EDLT — Fri, 24 May 2024 14:00:31 GMT

I didn't realize the peripheral connection power level is determined from the advertising power level. That is a helpful bit of information.

I don't imagine this applies for the central role, who may know nothing about the peripheral's TX power level. For the central, how does one setup the connection power level before connecting?

RE: How to specify default TX power at runtime for the nrf5340?

Einar Thorsrud — Fri, 24 May 2024 08:38:31 GMT

Hi,

Sorry, the link was wrong. I did not find the one I indended to link to again now, but it is essentially what is demonstrated in the HCI Power Control sample. This demonstragte how you adjust the Tx power on the host side (so the app core on he nRF53).

A key poin there, which is demonstrated by the sample but perhaps not very clearly, is that the Tx power used for advertising will be the initial (default if you like) Tx power for the resulting connection. So there is no need to explicitly set the Tx power for the connection(s) as long as you set it for the advertiser.

RE: How to specify default TX power at runtime for the nrf5340?

EDLT — Thu, 23 May 2024 14:23:26 GMT

Thanks, I understand the use of the HCI commands for setting the power on a per handle basis and use those. I was hoping for something like "sdc_default_tx_power_set" that can be triggered from the application core after the BLE stack is already initialized.

RE: How to specify default TX power at runtime for the nrf5340?

Einar Thorsrud — Thu, 23 May 2024 11:10:53 GMT

Hi,

You can use the approach shown in this post.