About removing the 32.768kHz crystal oscillator

[Rekolhy]

Hello,

While designing the hardware circuit for the CAAA WLCSP with internal LDO regulator setup on the nrf52810, I removed the 32.768kHz crystal oscillator and retained only the 32MHz crystal oscillator. During software debugging, I found that when using the k_msleep function alone, its counting is relatively accurate. However, after adding GPIO drivers, the k_msleep function frequently gets stuck and fails to proceed to the next step. Does the software require any special adaptation or adjustment when retaining the 32MHz crystal oscillator to resolve this issue?

Thank you very much.

[Rekolhy]

Thank you very much，
My issue has been resolved. I have an additional question: Can the system enter sleep mode and wake up periodically when using only a 32MHz crystal oscillator?
Thank you.

[Ressa]

Glad to hear it is working. Yes you can have only 32MHz external crystal and still enter and wake up from sleep mode, in that case internal LFRC will be used. 

Best regards,
Ressa 

[Rekolhy]

Hello,
Could you please provide relevant examples for entering system off mode and RTC wake-up from system off mode?
Thank you.

[Ressa]

Hi, 
You can check the below sample as it can be used for evaluating different power modes:
Bluetooth: Peripheral power profiling

Best regards,
Ressa

[PaKa]

Note: for GRTC in system off you need to have the 32KHz crystal mounted, this mode is not available with the LFRC

[Rekolhy]

Thanks for the reminder. May I ask which sleep mode I can enter and use the RTC for wake-up when only using a 32MHz external crystal?

[PaKa]

Power On All Idle is the mode with the lowest power consumption when using the LFRC. This means the device is active but everything can be stopped.