nrf5340 resets but does not halt on "mon reset" command in debugger

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

Priyanka — Fri, 04 Jul 2025 12:45:24 GMT

I would recommend checking like that too since you seem to have everything else correct. 🙂

Do let us know regarding the issue once you are able to get any leads, or in case you have any further doubts related.

-Priyanka

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

randomdude — Fri, 04 Jul 2025 12:34:27 GMT

Nevermind the capacitor placement in the schematics. In reality it looks a lot more like this, again, largely following the reference suggestion (inner layers hidden for readability):

By this point, the most likely cause really seems to be some kind of manufacturing defect.

Maybe now is the right time to ask my boss to buy an X-ray machine... 🙂

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

Priyanka — Thu, 03 Jul 2025 09:36:28 GMT

Hi,

[quote user="randomdude"]I assume this is what you meant by " REST"[/quote]

Yes, I meant RESET. Sorry for the typo.

[quote user="randomdude"]Apparently, my initial observation turned out to be wrong, and the behavior is not the same across all boards. Some seem to behave correctly, while others don't.[/quote]

Then this could be some soldering or other differences on the boards.

[quote user="randomdude"]nrf53-fanout.pdf[/quote]

The schematic seems to comply well with the reference design. I just have one comment though.

These are correct in terms of the number of capacitors and their values, but please make sure that these caps are placed as close to their pin on the SoC bacuse if they are far away from their corresponding pins, this can cause trouble.

This is how it's placed in the reference design:

-Priyanka

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

randomdude — Mon, 30 Jun 2025 13:30:07 GMT

Hi Priyanka,

as this is contract work for a client, I can't share a complete schematic of the project. The differences between both revisions are marginal and only apply to a few GPIO pins. The power supply and clock configuration hasn't changed between revisions, and matches the PDF I uploaded.

I actually did have the RESET (I assume this is what you meant by " REST"?) pin floating in both revisions, but I added a 10k pull-up to the board that was misbehaving, and it didn't make a difference.

But I've got a few more details about the behavior:

Apparently, my initial observation turned out to be wrong, and the behavior is not the same across all boards. Some seem to behave correctly, while others don't.

I can't make heads or tails of this, it all seems very odd. I still hope this helps a bit anyway.

Regards,

devzone.nordicsemi.com/.../nrf53_2D00_fanout.pdf

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

Priyanka — Wed, 25 Jun 2025 11:47:10 GMT

Hi,

Apologies for the delay in response. We are a bit understaffed at the moment due to the summer vacations here in Norway.

Thank you for understanding.

Since you are flashing the same firmware, same flashing method as well as debugging procedure, then it could only be a hardware difference in the two revisions that is causing this issue.

Please make sure that the REST pin is not floating in either revisions. Could you tell me what are the differences in both design?

I guess it would be a bit helpful if you could upload the schematics of both revisions so that I can take a look at it.

Regards,

Priyanka

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

randomdude — Tue, 17 Jun 2025 10:24:33 GMT

Hi Priyanka, Thanks for answering!

It's our own design, but I largely followed the nrf5340 QKAA reference layout 1_2 suggestion on both revisions.

Regards,

RE: nrf5340 resets but does not halt on "mon reset" command in debugger

Priyanka — Tue, 17 Jun 2025 09:47:23 GMT

Are you working with the nRF5340 DK? Or is it some other board?

If it's the DK, could you tell us the revisions of both boards?

Regards,

Priyanka