RE: nRF54L15 GRTC SYSCOUNTER accuracy

tmav — Mon, 10 Nov 2025 14:52:24 GMT

Hello Kazi.

Many thanks for your answer.

RE: nRF54L15 GRTC SYSCOUNTER accuracy

Kazi Afroza Sultana — Mon, 10 Nov 2025 13:54:29 GMT

Hello,

From the documentation ''Automatic synchronization of SYSCOUNTER with the internal low frequency timer for ultra-low power operation

Internal low frequency timer runs on LFCLK (32768 Hz clock)
Internal low frequency timer can run while the device is in System OFF mode''

The SYSCOUNTER runs off the fast clock (16MHz clock) but uses only LFCLK while SYSCOUNTER is in sleep state.

GRTC's timekeeping accuracy is determined by LFXO, not by the HFINT. The 16MHz HFINT is used for high resolution counting during active periods, it doesn't have any long-term effect because LFXO can resynchronize periodically.

So, I think you can use GRTC as timekeeper with an external LFXO as long as the quality of LFXO is good.

However, I have asked the team to make it assure. I will get back to you soon.

Thanks.

BR
Kazi