RE: RTC stops running after soft reset with WDT enabled

Remi.G — Wed, 02 Sep 2020 01:42:41 GMT

Thanks for the speedy reply!

I can confirm that disabling those lines fixes the issue both in the example and in my application.

To avoid modifying SDK code, I am actually using the following:

err_code = nrf_drv_clock_init();

APP_ERROR_CHECK(err_code);

nrf_drv_clock_lfclk_request(NULL);

nrfx_clock_lfclk_start();

which also works.

RE: RTC stops running after soft reset with WDT enabled

Vidar Berg — Mon, 31 Aug 2020 11:11:10 GMT

Hello,

Thank you for providing the code needed to reproduce this behavior, it's really helpful! It sounds like this issue may be the same as the one discussed here: https://devzone.nordicsemi.com/f/nordic-q-a/65329/bootloader-with-wdt-and-app_time which I'm still working on. I will continue to debug the problem and keep you posted.

Best regards,

Vidar

Update: I think this related to the behavior Håkon describes here (link) in that you have to start the LF clock start task even if the clock has been started by the WDT first. Removing the if condition in nrf_drv_clock_init() as shown below should fix the problem.

ret_code_t nrf_drv_clock_init(void)
{
    ret_code_t err_code = NRF_SUCCESS;
    if (m_clock_cb.module_initialized)
    {
        err_code = NRF_ERROR_MODULE_ALREADY_INITIALIZED;
    }
    else
    {
        m_clock_cb.p_hf_head      = NULL;
        m_clock_cb.hfclk_requests = 0;
        m_clock_cb.p_lf_head      = NULL;
        m_clock_cb.lfclk_requests = 0;
        err_code = nrfx_clock_init(clock_irq_handler);
#ifdef SOFTDEVICE_PRESENT
        if (!nrf_sdh_is_enabled())
#endif
        {
            nrfx_clock_enable();
        }

#if CALIBRATION_SUPPORT
        m_clock_cb.cal_state = CAL_STATE_IDLE;
#endif

        m_clock_cb.module_initialized = true;
    }

/* Mod: start LF clock regardless of WDT state */

//    if (nrf_wdt_started())
//    {
//        m_clock_cb.lfclk_on = true;
//    }
//
    NRF_LOG_INFO("Function: %s, error code: %s.",
                 (uint32_t)__func__,
                 (uint32_t)NRF_LOG_ERROR_STRING_GET(err_code));
    return err_code;
}