nRF52810 LF CLK source from stm32

RE: nRF52810 LF CLK source from stm32

ketiljo — Fri, 09 Nov 2018 14:54:53 GMT

Hi Andy

No, nor really, unless you set this pin as output low, it should not behave like this. Is the output pin from the STM connected directly to XL1 or do you have something in between?

cheers,

Ketil

RE: nRF52810 LF CLK source from stm32

andyf — Thu, 08 Nov 2018 16:50:46 GMT

Hi Ketil,

Thanks for the quick reply and apologies for the delay in responding.

The trace on the scope in the previous image is probing pin 2 on the nRF while it is not powered which confirms it the signal is reaching the right place. Do you know of anything in the initialisation of the pins on the nRF that could be affecting the STM's ability to drive the clock on this pin?

Thanks,
Andy

RE: nRF52810 LF CLK source from stm32

ketiljo — Tue, 06 Nov 2018 08:19:53 GMT

Hi Andy

That was very strange, the input of the oscillator should have very a high impedance. Unless you have a large resistor in series, the signal level should stay the same. Can you double check that the signal is actually connected to pin 2?

cheers,

Ketil

RE: nRF52810 LF CLK source from stm32

andyf — Mon, 05 Nov 2018 16:03:25 GMT

Hi Ketil,

Thanks for the quick response.

I have attached an image of what the CLK signal from the STM looks like when the nRF is switched off. As soon as I power the nRF this signal disappears and all I see is GND.

Thanks,
Andy

RE: nRF52810 LF CLK source from stm32

ketiljo — Mon, 05 Nov 2018 14:32:19 GMT

Hi Andy

We've taken a look at the code and the schematic. It all looks correct, no reason for this to fail. All register are set correctly and the clock input is also correct. XL2 should be grounded with a full swing signal, so that's correct as well. How does the input signal look like?

best regards,

Ketil Aas-Johansen