Unkwon Resets after Long runtime ; Several Hours

RE: Unkwon Resets after Long runtime ; Several Hours

Stian Røed Hafskjold — Fri, 08 Jul 2022 08:11:37 GMT

Hi,

[quote user="krisnov"]

When the reset pin ist activated the pin in RESETREAS is set as expected.

The problem is the other way around, reset pin is reported in RESETREAS but the pin was never set.

[/quote]

Yes, I understand that the problem is that RESETREAS is reported even if the pin was never set. So to figure out if these resets are actually related the internal pin reset circuitry or not, it would be nice to do some tests to narrow down the problem. Hence my questions in the previous reply. If you disable the pin reset functionality in UICR, do you still get resets? And if so, what is the RESETREAS now?

Note that in order to disable pin reset, the UICR will have to be erased, and you have to make sure that PSELRESET[n] is not rewritten by the firmware.

On the scope are you able to zoom in to about 10 us/div?

RE: Unkwon Resets after Long runtime ; Several Hours

krisnov — Mon, 04 Jul 2022 09:28:06 GMT

Hi Stian,

When the reset pin ist activated the pin in RESETREAS is set as expected.

The problem is the other way around, reset pin is reported in RESETREAS but the pin was never set.

In the scope picture line 1 (yellow) is the reset, it never goes below a treshold to become a valid reset.

In the scope picture line 2 (blue) is VDD supply. It has a dip in the voltage for a short time.

RE: Unkwon Resets after Long runtime ; Several Hours

Stian Røed Hafskjold — Wed, 29 Jun 2022 08:29:21 GMT

Hi Kristijan,

Just to figure out if this RESETREAS =1 is valid or not, can you try to do a power cycle and read the RESETREAS register afterwards, and check if it is 1? I have seen previously that capacitance on the reset pin may cause the rise of the reset pin to lag behind the power on reset, so that a false pinreset is reported.

Is pin reset in UICR enabled? Can you try to disable pin reset (erase UICR) and see if you still get these resets? Then we would know for sure if this is related to the reset pin or not.

The 52840 and 52832 are very similar so I would assume that the 300mV/300ms system reset is valid for 52840 as well.

Do you have any plots of the VDD fluctuations?

Are you reproducing these resets at normal indoor temperatures?

Best regards,
Stian

RE: Unkwon Resets after Long runtime ; Several Hours

krisnov — Tue, 21 Jun 2022 11:57:03 GMT

Hi Pryanka,

Sorry I forget that

We use the NRF52840. CKAA-D0.

Regards

Kristijan

RE: Unkwon Resets after Long runtime ; Several Hours

Priyanka — Tue, 21 Jun 2022 11:48:53 GMT

[quote user="PriyankaKesav"]What IC version are you using?[/quote]

Could you provide your version?

-Priyanka

RE: Unkwon Resets after Long runtime ; Several Hours

krisnov — Tue, 21 Jun 2022 10:52:10 GMT

Hi Pryanka,.

I investigated already the bits in RESTREAS.
As a matter of fact I wrote the result initially with with the support request

There is no question about which bits are set.

Could you connect me with some other support member that has a deeper knowledge about the reset procedure and the corresponding hardware ?

Regards Kristijan

RE: Unkwon Resets after Long runtime ; Several Hours

Priyanka — Mon, 20 Jun 2022 07:36:48 GMT

Hi,

You could try reading the RESETREAS for understanding the reason for the reset. If it shows PIN, then the reason must be power on reset.

There is also this errata. What IC version are you using?

-Priyanka

RE: Unkwon Resets after Long runtime ; Several Hours

krisnov — Fri, 17 Jun 2022 12:59:59 GMT

Hi Pryanka,

Please ignore first screenshot it was sent by mistake.

I refer to the second one. The data sheet says that the bit 1 in RESTREAS is set if the reset pin is activated.

BUT we have the case that the bit is set AND the reset pin was not set.

I am asking for if this is possible and how.

Than I added the screenshot as a possible explanation (reset can be set due to voltage change of 300mV in short time). But it is from the NRF52832.

And may other question, if the same can happen with NRF52840.

Regards Kristijan

RE: Unkwon Resets after Long runtime ; Several Hours

Priyanka — Fri, 17 Jun 2022 11:07:46 GMT

Hi,

I am sorry but I did not quite understand the query. The screenshot provided shows the description for RESETREAS of the nRF52840, hence it is valid for the nRF52840. Maybe you could take a look at the various reasons for reset in the documentation for RESETREAS.

Regards,

Pryanka

RE: Unkwon Resets after Long runtime ; Several Hours

krisnov — Fri, 17 Jun 2022 08:27:13 GMT

here is the right screenshot: