How to make the Intermittent application with GRTC and LFXO while asleep.

[shibuta]

Hi.

I have been investigating how to use GRTC and LFXO for LFCLK with nRF54L15DK.
In my goal, I would like to make the Intermittent application with sleep and GRTC that works with LFXO even if the MCU stay asleep.

I found the library(nrfx_grtc.h), but I couldn't find the sample named 'GRTC' with the library from ncs 3.0.0.

Do you know how to manipulate the API of GRTC, and properly to write the prj.cof ?

Best regards.

[Vidar Berg]

Hello,

The system clock in Zephyr is already running off the GRTC (or the RTC if you're using a nRF52/53/91 series device). So, let's say you have a single threaded application, you can make it wake up periodically using Zephyr primitives such as k_msleep(). It will be in System ON mode  between the wake ups.

int main(void)
{
    while (1) {
        printk("Woke up. Going back to sleep\n);
        k_msleep(1000);  // Sleep for 1000 ms
    }
    
    return 0;
}

https://docs.nordicsemi.com/bundle/ncs-3.1.0-preview1/page/nrf/test_and_optimize/optimizing/power_general.html 

Best regards,

Vidar

[shibuta]

HI.
Thank you for replying, but where did you find GRTC automatically works responding to power state?
Indeed, I see the k_sleep() go sleep, but I couldn't find that automatic clock source change in your URL document.
The document seemes to state some techniques for power saving.

Anyway, I will try obeying your suggested document.
If I confirm the power consumption become lower, I will report them.

Best regards.