RE: nrf54L15 RF match

Einar Thorsrud — Tue, 07 Apr 2026 13:06:52 GMT

Hi,

The nRF54L15 lets you output the LFXO directly on P0.04, and this method is suited for measuring the LFXO accuracy. You can do that using this short application:

#include <hal/nrf_gpio.h>
#include <hal/nrf_grtc.h>
#include <haly/nrfy_grtc.h>
#include <nrfx_grtc.h>

#include <zephyr/drivers/gpio.h>
#include <zephyr/kernel.h>

#define PIN_NUM NRF_DT_GPIOS_TO_PSEL(DT_ALIAS(toggler), gpios)

int main(void)
{
	/* Output 32.768 kHz clock on pin P0.04 */
	nrfy_grtc_clkout_set(NRF_GRTC, NRF_GRTC_CLKOUT_32K, true);
	k_sleep(K_FOREVER);

	return 0;
}

Note that if the board use P0.04 for other things you need to modify the board file. If building for the DK which use P0.04 for button 3, add this in an overlay file:

/ {
	aliases {
		/delete-property/ sw3;
	};
};

/delete-node/ &button3;

Attached full project for reference: devzone.nordicsemi.com/.../grtc_5F00_32768hz_5F00_out_5F00_nrf54l15.zip.

Regarding matching, measuring other than 50 ohm at J1 is not unexpected and not indicative of a problem. See this post. Tuning of the match should be done by measuring output power and harmonics.

Note that if you want assistance on this you can make a private case where you upload your schematics and layout for a HW review, and once that looks good, we may also assist in tuning the HW.