nRF21540 on custom PCB won’t activate; works fine with nRF21540-EK + nRF54L15DK

[ChenyangR]

Hi,

Issue

• With the official nRF21540-EK + nRF54L15DK setup, my app/config works: advertising, connections, and PA/LNA behavior are all OK.

• On my custom PCB (nRF54L15 + nRF21540-QDAA), the PA seems not enabled: the phone rarely finds the device, and RSSI does not improve when I “enable” the FEM.

• Conclusion so far: software stack is sane (proven on EK+DK), but on my board the nRF21540 path likely isn’t being driven/selected.

• SoC: nRF54L15 (nrf54l15dk/nrf54l15/cpuapp)

• FEM: nRF21540-QDAA

• NCS: v3.1.0

Hardware connection:

Overlay

/ {
	nrf_radio_fem: name_of_fem_node {
	   compatible  = "nordic,nrf21540-fem";
	   tx-en-gpios = <&gpio1 11 GPIO_ACTIVE_HIGH>;
	   rx-en-gpios = <&gpio1 12 GPIO_ACTIVE_HIGH>;
	   pdn-gpios   = <&gpio1 2 GPIO_ACTIVE_HIGH>;
		mode-gpios   = <&gpio1 3 GPIO_ACTIVE_HIGH>;
		tx-en-settle-time-us = <27>;
		rx-en-settle-time-us = <12>;

 };
}; //54L15

conf file:

#FEM general
CONFIG_NFCT_PINS_AS_GPIOS=y
CONFIG_MPSL_FEM=y
CONFIG_MPSL=y
CONFIG_MPSL_FEM_NRF21540_GPIO=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y
CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=20
CONFIG_MPSL_FEM_NRF21540_RX_GAIN_DB=13
CONFIG_MPSL_FEM_NRF21540_RUNTIME_PA_GAIN_CONTROL=y

[ChenyangR]

I think I have solved the problem, I use gpio 2 &3 which is used for NFC, but forget to open it in overlay. 

When I add the below overlay code it can work:

&uicr {
 
      nfct-pins-as-gpios;
 
};