Configure and Debug Clock Control

[notkuroneko]

Hello!

I don't know if there is a way to configure a nrf52832-QFAA's clock source on my custom board software-wise.

Just a disclaimer but please correct me if I'm wrong anywhere because there is little to no reliable tutorial for clock control and I'm also just as confused as you might be when looking at the code snippet I'm providing.

We were planning to use the 32MHz high frequency internal RC:

This is the snippet for the clock control section of the application:

dts file:

```

&clock {

    status = "okay";

   

    lf_clk {

        clock-source = <0>; /* RC oscillator */

        calibration = <1>; /*optional; default is true for RC*/

    };

};

```

defconfig file: 

```

# Enable Clock Control

CONFIG_CLOCK_CONTROL=y

CONFIG_CLOCK_CONTROL_NRF=y

# Enable DCDC and internal low freq clock

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y 

```

main.c

```

int start_hfclk(void)

{

    const struct device *clock_dev = DEVICE_DT_GET(DT_NODELABEL(clock));

   

    if (!device_is_ready(clock_dev)) {

        LOG_ERR("Clock device not ready");

        return -1;

    }

    // Start HFCLK - clock_control_on returns 0 on success

    int ret = clock_control_on(clock_dev, CLOCK_CONTROL_NRF_SUBSYS_HF);

    if (ret != 0) {

        LOG_ERR("Failed to start HFCLK: %d", ret);

        return -1;

    }

    // Wait for HFCLK to be ready

    int timeout = 5000; // Timeout in milliseconds

    int elapsed = 0;

    while (elapsed < timeout) {

        enum clock_control_status status = clock_control_get_status(clock_dev, CLOCK_CONTROL_NRF_SUBSYS_HF);

        if (status == CLOCK_CONTROL_STATUS_ON) {

            break; // HFCLK is ready

        }

        k_msleep(10);

        elapsed += 10;

    }

    if (elapsed >= timeout) {

        LOG_ERR("HFCLK ready timeout");

        return -1;

    }

    // Workaround for anomaly [68]: Add delay to ensure clock stability

    k_msleep(1); // Small delay to ensure HFCLK is truly stable

   

    LOG_INF("HFCLK is ready and stable");

    return 0;

}

```

The application works fine at first but then for some reason the clock_control_on() function returns error code 11 and stopped working ever since. I'm not sure if it's a problem software-wise or hardware-wise, since my group is using a custom designed board. My groupmate already made another private ticket for hardware debugging, but I want to see if there's any possible solution software-wise because this doesn't seem ideal.

Thank you for your help, and sorry if this code snippet confuses you in any way.

Regards,

Jackie

[Vidar Berg]

Hello Jackie,

The CPU and other peripheral's requiring the HF clock runs by default from the internal RC oscillator (HFINT) and the clock_control_on() is to request the more accurate crystal oscillator (HFXO), but it seems like it is failing to ramp up as it's returns with -EAGAIN (-11). Could you please try to run the snippet I posted here and see if the program is able to exit the while loop  RE: MPSL ASSERT: 112, 2134 if using multiple BLE communication  ?

Best regards,

Vidar

[notkuroneko]

Thank you Vidar for your support!

We have a few prototypes for our hardware at the moment, i will try to run that on the boards that are not functioning.

I'll assume that the code for starting the clock manually should work and I'll debug it alongside your snippet.

Once again, thank you! I'll update once we get this running.

Best regards,

Jackie