ncs 2.3.0 FEM not working!

[Wangshuhai]

Hi Nordic.

   I‘m using NCS 2.3.0, and trying to add FEM to the lbs example program.

   I created the nrf5340dk_nrf5340_cpuapp.overlay in the lbs example program and released the corresponding pins to the network core. Then, I created a childimage folder and created the nrf5340dk_nrf5340_cpunet.overlay , added the 21540 fem into file.

   I check the build/hci_rpmsg/.config the CONFIG_MPSL_FEM and CONFIG_MPSL_FEM_NRF21540_GPIO is opened , but there not effect ,

   I migratethe project back to 2.2.0, and it turned out to be ok

  peripheral_lbs_230.zip

Can your give me some advise，thanks!

[Hieu]

Hi wangshuhai,

Your description is strange, because it is NCS v2.2.0 which has a defect that prevents FEM setup to achieve the desired TX Power (see DRGN-18568 in the list for v2.2.0 here: Known Issues).

How are you checking whether the setup work or not?

Please review your test. Also, please note that from NCS v2.2.0, in addition to the configuration you are listing, you also need to add CONFIG_BT_CTLR_TX_PWR_ANTENNA. However, as noted above, NCS v2.2.0 has a known issue that prevents such setup to achieve the desired TX Power. This is fixed in NCS v2.3.0.

Hieu

[Wangshuhai]

Hi Hieu, 

   sorry , My mistake not say clear . I changed the power in NCS 2.3.0 , but I not change power in NCS 2.2.0，at little different.

I commented the CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=20  In NCS 2.2.0 . other config not change.

[Hieu]

Hi wangshuhai,

The expectation would be that, due to a known issue, on v2.2.0, FEM setup does not work correctly. On v2.3.0, the known issue is fixed.

On v2.3.0, I have tested and see that Peripheral LBS can advertise with the expected TX Power with the following Kconfig:

CONFIG_MPSL_FEM=y
CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=10
CONFIG_BT_CTLR_TX_PWR_ANTENNA=10

Please also be informed that it is the Easter holiday here, so responses on DevZone can be delayed, and I will be out of office from today and return Tuesday Apr 11. 

[Wangshuhai]

Hi Hieu

    Thanks for your help, I'll try! and Wishes you to have a happy vacation!