Hello everyone,
I am doing some testing regaring advertising TX power on peripheral side with BLE.
I am using NCS version 2.6.1.
Hardware: nRF52840 Dev Kit
My tests have so far been based on the given sample: HCI power control. The function of interest is:
At the very end of the function I have added a log message to log the argument of the function tx_pwr_lvl and the actual TX power level as supplied in the response:
Expected: That both the TX power I am trying to set and the TX power in the response are identical.
Instead, both numbers differ:
TX - tried to set: -10, actual: -10
TX - tried to set: 5, actual: 2
TX - tried to set: 20, actual: 18
TX - tried to set: -40, actual: -30
TX - tried to set: 0, actual: -2
Now I have some questions:
- Why is there a difference between the TX power I try to set and the actual TX power configured by the controller?
- Where does this difference come from?
- What can I do to get a minimal difference between wanted and actual TX power?
- Where can I find documentation regarding this behaviour? I expect I have to look into the softdevice specification? But I was not able to find a link from the application interface ov the BLE stack to the softdevice specification. Example:
- The following link describes the command, but no I was not able to find any documentation giving more information than its existance: e.g. https://docs.zephyrproject.org/apidoc/latest/hci__vs_8h.html
Thank you for your help!
Markus