Configure external clock 32.768K

[Josh_1]

Hi

Please advise how to configure external clock instead using the internal.

Thanks

[Josh_1]

Additional issue is what is the configuration for using Clock instead of crystal, e.g connecting LF (32.768) external clock to XL1 and XL2 to GND.

Thanks  

[awneil]

You haven't said what chip you're using.

Have you checked what the Product Specification for your chip says?

Take a look at the Rigado blog post linked here:

https://devzone.nordicsemi.com/f/nordic-q-a/46564/error-133-0x85-gatt-error-on-nrf52840/185362#185362

Although it is about using the internal RC, it does give some explanation of what all the settings are.

Also, look at the comments in the sdk_config.h file - they also give brief descriptions of the settings.

For viewing & editing the sdk_config.h file, see:

https://devzone.nordicsemi.com/f/nordic-q-a/45362/cmsis-configuration-wizard---option-highlighting/178343#178343

[Simonr]

Hi Josh

As awneil says, please see the sdk_config.h file and particularly the NRFX_CLOCK_CONFIG_LF_SRC define.

For configuration of the clock versus crystal, please refer to this table.

Best regards,

Simon

[Josh_1]

Hi,

I`m using nRF52832.

Can I use external 32.768K square wave Oscillator?

If yes what is the hardware and software configuration?

Thanks

[Simonr]

Hi Josh

Yes, you can. It's important that the clock applies a rail-to-rail clock signal. Please read more on how to configure the 32.768 kHz oscillator here. 

Best regards,

Simon