How to reset the uptime after a reboot?

RE: How to reset the uptime after a reboot?

Nick Ewalt — Thu, 24 Apr 2025 20:20:02 GMT

You need to set NRFX_GRTC_CONFIG_CLEAR_AT_INIT. See:

devzone.nordicsemi.com/.../grtc-is-not-cleared-on-reset-causes-zephyr-sys_clock-to-break-when-uptime-20-hours

RE: How to reset the uptime after a reboot?

vesrup — Wed, 26 Feb 2025 12:50:56 GMT

Would like to add, that doing the "button" sample and initiating the reboot on the button press, uptime does not in fact reset on the 54l15 DK. It is probably a problem with the 54l15 chip, which we are using on our custom board. Hopefully it will be fixed on the next SDK update.

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 14:21:05 GMT

As I understand it, yes, this parameter initializes the GRTC.

RE: How to reset the uptime after a reboot?

Jakob Ruhe — Tue, 25 Feb 2025 14:19:20 GMT

Good that you found it! I had no idea about this. Is this somehow related to the configuration parameter `CONFIG_NRF_GRTC_START_SYSCOUNTER`?

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 13:59:21 GMT

Managed to fix it by calling

NRF_GRTC_S->TASKS_CLEAR = 1;

before initiating the reboot.

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 13:39:07 GMT

Yes, pulling the reset pin or resetting the power does reset the uptime, however we need a way to do that using firmware, not hardware.

RE: How to reset the uptime after a reboot?

Sigurd — Tue, 25 Feb 2025 13:31:14 GMT

Hi!
A pin reset or a power on reset will reset the GRTC counter.

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 13:21:21 GMT

Thank you for trying to help.

RE: How to reset the uptime after a reboot?

Jakob Ruhe — Tue, 25 Feb 2025 13:13:20 GMT

OK. It was a very long shot indeed. I have no more ideas at the moment. I think you need to share more about your board and how you have configured it, in order for others to help you troubleshoot further.

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 12:59:24 GMT

First time booting:

startup_test: b1: 0, b2: 42

Second time booting after calling NVIC_SystemReset():

startup_test: b1: 0, b2: 42

No change.

RE: How to reset the uptime after a reboot?

Jakob Ruhe — Tue, 25 Feb 2025 12:52:29 GMT

I see. Strange.

What output do you get if you call this function twice during each boot?

void startup_test(void)
{
    static int b1;
    static int b2 = 42;
    LOG_INF("%s: b1: %d, b2: %d", __func__, b1, b2);
    b1++;
    b2++;
}

Since I know nothing about how much you have customized for your board I just want to check that the `bss` and `data` sections are initialized correctly by the reset handler. If they are not, you would probably see other, more severe, problems. But it should be quick to test and rule out at least.

RE: How to reset the uptime after a reboot?

vesrup — Tue, 25 Feb 2025 12:24:28 GMT

I tried checking k_uptime_get() and its not reset after the reboot.

Using sys_reboot(); or NVIC_SystemReset(); does perform a reboot. Logs clearly indicate that the device is rebooted, by showing the startup of the bootloader and the startup process of our device, but the uptime is carried over, instead of starting at 0.

Uptime is printed first things first with the logging system:

[00:47:01.025,216] <dbg> watchdog: primary_feed_worker: Feeding watchdog
[00:47:31.025,280] <dbg> watchdog: primary_feed_worker: Feeding watchdog
[00:48:01.025,344] <dbg> watchdog: primary_feed_worker: Feeding watchdog

I tried reproducing the problem by using the "button" sample. Constantly printing out uptime by using k_uptime_get() and calling NVIC_SystemReset() when the button is pressed, the uptime does reset. I was using the N52832 DK, since it is the only one I had on hand. However, on our device, printing k_uptime_get() on boot and then initiating NVIC_SystemReset() does not reset the uptime.

RE: How to reset the uptime after a reboot?

Jakob Ruhe — Tue, 25 Feb 2025 11:28:51 GMT

The Zephyr function `k_uptime_get()` should return the uptime in milliseconds since boot.

The function `NVIC_SystemReset()` should perform a reboot. Can you verify that your system actually reboots?

How do you read the uptime in your system?

Can you reproduce your problem on a standard development board?

Can you share a minimum example that makes it possible for others to reproduce your problem?