FEM Support For Radio Test Example on custom board

[Brosnan]

Hi,

I needed assistance to get the SKY66112-11 FEM working with the Radio Test Example, for certification testing (FCC, CE etc). I am using the NCS 1.5.1 SDK. I have followed the following link. I am using a custom board with nRF52832 SoC and it has the LFXO present.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_radio_fem.html#ug-radio-fem

I have made changes to the Configuration file of the project and added the device tree node as mentioned in the following forum post.

https://devzone.nordicsemi.com/f/nordic-q-a/74433/ncs-v1-5-1-pa-lna-support-for-bluetooth/306783#306783

Are there any addition changes required beside these to be done to get the FEM working? For instance I need to initialize the other 2 control gpios on the FEM which are of fixed logic levels, how should i go ahead adding those to the project?

Also are the any changes required to be done in the main application file itself of the Radio Test code to add support for the MPSL lib or just the project configuration settings are enough? 

PS: Just wanted to mention that I tried running the Radio Test Example directly without adding the support for the FEM and that works as expected. So this tells me that the COM lines gpio changes I did in the dts file worked as it should and the crystal is fine too.

Thanks in Advance

[run_ar]

Hi,

For TX see: Transmit sequence Enable the ePA at the same time as TASKS_TXEN. The ramp up time of the radio is 40µs which is usually enough. Alternatively start a timer at this event an enable the ePA closer to the EVENTS_READY event, but some time is needed for the ePA to ramp up as well. Use EVENTS_END to disable the ePA.

For RX, see:Receive sequence. Similar as tx, use TASKS_RXEN. 40µs ramp up. Use EVENTS_END to disable the eLNA (if there is one). If you are not using a eLNA, just keep the ePa in bypass mode when TX is disabled for the test.

[Brosnan]

Thanks run_ar I'll test this out.