Support for PA/LNA and Thread NCP

[MarcoLG]

Hello,
we are using a usb dongle where we have a NRF52840 and RFX2401 PA+LNA frontend.

The latter can be controlled with TX_EN and RX_EN pins.
8512.NRF52840_USB_DONGLE_PA (2).pdf
Please see attached schematic.

https://it.aliexpress.com/item/4000396608137.html

We saw from the documentation that automatic control of frontend can be done with the ENABLE_FEM feature:

https://infocenter.nordicsemi.com/topic/sdk_tz_v4.1.0/shared_fem_feature.html

We would like to configure that in the NCP example for thread in order to get our thread radio to use also the LNA. We are using the source code from PCA10059.

We are trying to do that, as mentioned in the SDK documentation, by defining the  ENABLE_FEM variable in the preprocessor options and FEM_CONTROL_DEFAULT_PA_PIN and FEM_CONTROL_DEFAULT_LNA_PIN in the sdk_config.h

However, after deploying the software to the usb dongle, the TX_EN and RX_EN lines are not switched.

Is there something we are missing?

Thanks

[Kenneth]

I don't know if it is enough to set the preprocessor defines. You likely also need to call nrf_802154_fem_control_cfg_set in addition, or possible PlatformFemSetConfigParams  in OpenThread.

[Rob C]

Check out this https://groups.google.com/g/openthread-users/c/PpGYsTLcfQQ/m/t0mHS7qSAgAJ discussion in the openthread users group.  At present, you need to make a couple changes to OpenThread source, then re-build the libraries used in your application project.

Stuart at VRT systems has a fork of OpenThread that automates this process more automated, particularly if you can use a standard NCP build output.  Also note if you're using your NCP in an OpenThread Border Router, you're probably going to want to migrate to the RCP architecture (vs. NCP, which is being deprecated in otbr).