Softdevice doesn't turn on HFCLK

[shai.c]

Hi,

We build a new board based on nRF52833 wlcsp,

I tried to run a simple code with BLE peripheral (ble_app_uart example), and I noticed that the HFCLK is not working (Tested with scope)

Using s140_nrf52_7.0.1 softdevice

When I'm running the following code:

NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
NRF_CLOCK->TASKS_HFCLKSTART    = 1;

/* Wait for the external oscillator to start up */
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)
{
}

while (1)
{

}

that only turning on the HFCLK it works good (tested with scope)

What can be the problem of softdevice to turn on the HFCLK?

[Sigurd]

Hi,

The SoftDevice will only request the HFCLK when it needs to. I.e. when it uses the RADIO. Only requesting the HFCLK when needed lowers the power consumption.

If you want the SoftDevice to keep the HFCLK running, use the function sd_clock_hfclk_request()

ble_app_uart example

 Do you see the device advertising, if you use nRF Connect for mobile to scan for the device ?

[shai.c]

No, the device isn't advertising

[Sigurd]

shai.c said:

No, the device isn't advertising

 Do you have a LF Crystal on your custom board?

[shai.c]

No

[Sigurd]

Try using the internal LFRC oscillator instead. In sdk_config.h set NRF_SDH_CLOCK_LF_SRC to 0, NRF_SDH_CLOCK_LF_RC_CTIV to 16, NRF_SDH_CLOCK_LF_RC_TEMP_CTIV to 2, and NRF_SDH_CLOCK_LF_ACCURACY to 1