How to add Skyworks fem to nrf5340 audio

[LandyWang]

Hello,

I am using nrf5340 audio sample with the custom board. The nRF Connect SDK version I used is v2.7.0.

I referred to this post and tried to add skyworks fem to my nrf5340 audio application.

The following is the part I modified:

nrf5340_audio_dk_nrf5340_cpunet.overlay

/ {
    nrf_radio_fem: pa_lna {
        compatible = "skyworks,sky66112-11", "generic-fem-two-ctrl-pins";
        ctx-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
        ctx-settle-time-us = < 23 >;
        crx-gpios = <&gpio1 5 GPIO_ACTIVE_HIGH>;
        crx-settle-time-us = < 5 >;
        cps-gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
        tx-gain-db = < 13 >;
        rx-gain-db = < 14 >;
    };
};
&radio {
	fem = <&nrf_radio_fem>;
};

nrf5340_audio_dk_nrf5340_cpuapp.overlay

/ {
    nrf_radio_fem: pa_lna {
        compatible = "skyworks,sky66112-11", "generic-fem-two-ctrl-pins";
        ctx-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
        ctx-settle-time-us = < 23 >;
        crx-gpios = <&gpio1 5 GPIO_ACTIVE_HIGH>;
        crx-settle-time-us = < 5 >;
        cps-gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
        tx-gain-db = < 13 >;
        rx-gain-db = < 14 >;
    };
};

prj.conf

CONFIG_MPSL=y
CONFIG_MPSL_FEM_ONLY=y
CONFIG_MPSL_FEM_SIMPLE_GPIO=y

But it doesn't seem to work.

Is there any way to add skyworks fem to nrf5340 audio application?

[Elfving]

Hi again, and sorry about the wait.

I see. Then I suspect that it is not enabled.

I bet there either is a config or two that has been overlooked, or maybe a config that we've forgotten to add to the child image, as 5340 allows you to have a separate set of configs for the netcore child-image.

Have you followed the steps outlined here?

Regards,

Elfving

[LandyWang]

Elfving said:

Have you followed the steps outlined here?

I've followed most of the steps listed here to modify the code, as the parts I posted above.

But I don’t quite understand with the step 4 of the document. Does it mean creating a child image/hci_ipc.overlay file to the nrf5340 audio application? But in NCS v2.7.0, the child image has been replaced by sys build. What should I do to apply the devicetree node to the network core?

I tried adding hci_ipc.overlay in sysbuild/ipc_radio, but it seems that fem has no effect.

Then,I added a child image folder in the nrf5340 audio application and put it in hci_ipc.overlay, but fem still had no effect.

[hci_ipc.overlay]

/ {
    nrf_radio_fem: pa_lna {
        compatible = "skyworks,sky66112-11", "generic-fem-two-ctrl-pins";
        ctx-gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
        ctx-settle-time-us = < 23 >;
        crx-gpios = <&gpio1 5 GPIO_ACTIVE_HIGH>;
        crx-settle-time-us = < 5 >;
        cps-gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
        tx-gain-db = < 13 >;
        rx-gain-db = < 14 >;
    };
};
&radio {
	fem = <&nrf_radio_fem>;
};