Use TCXO as LFXO (nRF52)

[mzi]

Hi, I would like to know, whether it is possible to use a TCXO with single output as a LFCLK source, i.e. connecting the TCXO output only to XL1, instead of connecting an xtal between XL1 and XL2.

Thanks,

Martin

[Hung Bui]

Hi Martin,

On nRF52, the HFCLK was not made to work with external clock source other than the Xtal.

[mzi]

And I guess it is the same with LFCLK?

[RK]

You guess wrong - you can use an external source for the LFCLK. The information about that including the type of signals permissable and the pin connections, are all documented in the manual.

[mzi]

Thanks RK! I found the information in the online manual right now, I was working with PDF version of the manual until now where this information was missing completely. My bad.

[Hung Bui]

@mzi: It's actually available at section 19.2.4 nRF52632_PSv1.1.pdf

[inushii]

Hello, Could you please expand on why a 32MHz TXCO or other external clock source cannot be used with the HFCLK? Thank you!