RE: How to configure hci_pwr_ctrl demo to support nrf21540dk

lcj — Thu, 13 Nov 2025 12:55:57 GMT

Ok. Thank you. Looks like that worked:

I see the power being set to 20 and the reading of the power at 20.

RE: How to configure hci_pwr_ctrl demo to support nrf21540dk

Einar Thorsrud — Tue, 11 Nov 2025 12:29:11 GMT

Hi,

Using the DK you can enable runtime dynamic power control and FEM by adding these configs to prj.conf in the hci_pwer_ctrl sample:

CONFIG_MPSL_FEM=y
CONFIG_MPSL_FEM_NRF21540_GPIO_SPI=y
CONFIG_MPSL_FEM_NRF21540_RUNTIME_PA_GAIN_CONTROL=y

And as you write, you can modify the txpower array to test other values, for instance:

static const int8_t txpower[DEVICE_BEACON_TXPOWER_NUM] = {20, 10, 4, 0, -3, -8,
							  -18, -30};

No other changes should be needed, as the board files for the DK has the other configurations that are needed (for custom boards, you would have to do as shown under Enabling GPIO+SPI mode support for nRF21540).

The Rx gain can be configured statically, but there is no support for dynamic Rx gain adjustment using CONFIG_MPSL_FEM_NRF21540_RX_GAIN_DB.