NRF52840 About the 32.768kHz crystal oscillator (LFXO)

[Kono Kohei]

Is the GPIO pin in a reset state until the start-up time of the 32.768kHz crystal oscillator?

[Sigurd Hellesvik]

Hi,

It sounds like you are asking for a reason.
If I may: Why do you ask about this?

I try to best understand the customer's use-case before answering the question to give the best possible answer.

Regards,
Sigurd Hellesvik

[Kono Kohei]

I would like to consider whether it is necessary to delay the input signal of the microcontroller peripheral circuit until the crystal oscillation stabilizes and take care of the microcontroller so that it does not malfunction.

[Jared]

Hi,

By default the microcontroller will use the internal LFRC oscillator, I don't think you can tell based on the crystal oscillator whether the CPU is in reset mode or not. Instead, you should base it on the level of VDD supply, as long as you are within the VDD +0V3 max limit, then you should be Ok and not damage the microcontroller.

regards

Jared