nRF5340 FEM

[yas745]

Hello,

I have three questions regarding FEM.

#1 According to the following URL, FEM function is supported only for nRF52 series.

Would the FEM function be available on BL5340 as well?

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.0/nrfxlib/mpsl/README.html

 

#2 The header file of “mpsl_fem_disable” function(described in the following URL) exists at "v2.0.0\nrfxlib\mpsl\include\protocol\mpsl_fem_protocol_api.h".

In order to see the detail, could you tell us where the function(source code like .c) exists?

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/mpsl/doc/api.html?highlight=dppi#c.mpsl_fem_disable

 

#3 Could you tell us if there is something that should be added in order to use FEM function on BL5340 + Peripheral_uart project?

Regards,

[JONATHAN LL]

Hi,

The nRF5340 can also use a FEM, we have in our Thingy53 product the nRF5340 and the nRF21540. So it is possible. 


https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/mpsl/doc/api.html?#mpsl-fem 

There is even a example here Working with RF front-end modules — nRF Connect SDK 2.0.99 documentation (nordicsemi.com) on testing the FEM with the nrf5340.

Would the FEM function be available on BL5340 as well?

The if the BL5340 module can integrate a FEM in a way then that should be doable. 


There is some example code here: sdk-nrf/subsys/mpsl/fem at v2.0.2 · nrfconnect/sdk-nrf · GitHub , but seems to be some changes in master so that is something to consider. 


So building for the nRF5340DK with the nRF21540 FEM as a shield you can use the following as a command to build

west build -b nrf5340dk_nrf5340_cpuapp -- -DSHIELD=nrf21540_ek -Dmultiprotocol_rpmsg_SHIELD=nrf21540_ek 

So using a BL5340 module together with a FEM should work much in the same way, you would need to map the correct pins, create a board file or use a overlay file. 

3 Could you tell us if there is something that should be added in order to use FEM function on BL5340 + Peripheral_uart project?

Looks like the module dos not by default have a FEM, so this would need to be tied in to the RF section of the module. Then you would need to connect the rest of the pins to that it can be controlled. Then add the whatever is needed by the FEM to work in SW. We dont relay have examples for this for any FEM, but can always create a new Devzone ticket with the specific project and setup in mind to smooth out any quirks. 


Regards,
Jonathan

[yas745]

Hi,

Thank you for the answer.

I understood that FEM can be used in nRF5340.

I would appreciate it if you could tell us about Question #2.

Regards,

[JONATHAN LL]

yas745 said:

I would appreciate it if you could tell us about Question #2.

There are no C files available publicly it is closed source. 

This is the closest to a C file you can get is probably this.
https://github.com/nrfconnect/sdk-nrfxlib/blob/f44027395ff417dddbb3b34f5a79579f62229d98/nrf_802154/sl/sl_opensource/src/nrf_802154_sl_fem.c#L109 

Regards,
Jonathan