Separate transmit power setting for BLE and Thread when using MPSL

[Jon]

Hello,

I have a design where I am using an nRF52840 along with a SKY66112-11 and am using Zephyr/MPSL for both BLE and Thread. Some questions:

1) The .dts node has pa_gain_db and lna_gain_db parameters, which default to ~20dBm and ~11dBm for the skyworks part. What are these parameters actually used for by the MPSL library? Do they affect CSMA thresholds, etc?

2) How do I reduce BLE transmit power such that BLE still operates at ~0dBm (which is our desired operation for BLE) while still allowing the Thread packets to transmit at high power?

I noticed that there is a CONFIG_BT_CTLR_TX_PWR setting in Zephyr but that does not seem to have any effect.

Thanks

Jon

[Susheel Nuguru]

Honestly speaking, I have not tried to control power with BLE/Thread combo in Zephyr, but CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL should expose HCI commands to write and read the TX power. Can you give me your project and your attempt of writing these HCI commands so that I can try to dig into it and figure out what else needs to enabled for this feature to work.

[Jon]

I don't think I can provide our project since it part of the CHIP (Matter) SDK development. If there is a BLE/Thread (on Zephyr) example you can point me to with the correctly-configured setup that I can evaluate I can probably work from there. Specifically, I need an example that:

a) Configures Thread transmit power at +0dBm

b) Configures BLE transmit power at -20dBm (e.g., advertisements are transmitted at -20dBm)

or alternatively

a) Provides some sort of callback from MPSL to the application layer before any Thread or BLE operations such that the the application can change power and/or reconfigure PA/LNA on FEM differently between BLE and Thread packets.