RE: why I cannot start external xo.

nick yong — Tue, 14 Jan 2025 16:12:47 GMT

thanks. I will try .
I find several code for xtal . I will try.

Håkon Alseth — Mon, 13 Jan 2025 12:44:15 GMT

Hi,

On boot, it's the HFINT (64 MHz RC oscillator) that is sourcing the system.

The HFXO needs to be explicitly started if your firmware requires it.

The simplest form is like this:

NRF_CLOCK->TASKS_HFCLKSTART=1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

If you hang in the while-loop, there is likely an issue with your soldering or loading caps.

Please share the xtal used and the value of C19 (and either C18 or C20?).

Kind regards,

Håkon

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