NRF54L15- Using external 32kHz source for LFCLK

[JTP]

Can the NRF54L accept a CMOS output clock signal on XL1? The NRF52s could do this via clock source register settings but such a configuration is not listed in the NRF54 datasheet.

Currently developing a board utilizing an NRF54L15 and another MCU. Both utilize 32kHz clocks and it would be useful for us to drive both from the same external oscillator. Sending the GRTC clock output to the other MCU isn't an option here.

[Simonr]

Hi James

I think this should be possible (similar to the nRF52 series) by just connecting the oscillator to XL1, but I need to check with the product manager. Most likely it just hasn't been added to the datasheet yet. I'll let you know when I hear from them.

Best regards,

Simon

[JTP]

Thank you Simon,
Another question, if we are using an external oscillator as a 32k source on XL1, could P1.01 be used as GPIO or is it always set as XL2?

[Simonr]

The following is also just what was true for the nRF52 series, so it will also need confirmation from the product management team. The config to enable or disable the external LF clock will set both XL1 and XL2 I'm afraid, so you can't use P1.01 as a GPIO while using an external 32kHz source. It must be left floating.

Best regards,

Simon