Noise from power profiler analysis

RE: Noise from power profiler analysis

Einar Thorsrud — Tue, 23 Feb 2021 11:56:39 GMT

Hi,

[quote user="Ripitchip00"]Is there a way to repair it ? [/quote]

I cannot really say, but if it is an issue with bad contact (let's say bad soldering because of mechanical strain or similar) you could try to find it and fix it. This was jus tan idea, though - I cannot say for sure that is part of the problem.

Regarding the general behaviour you see I am not able to reproduce or find similar past reports. Just as a shot in the dark, could you try to re-flash the onboard debugger on the DK's and see if that has any effect? You can put the debugger in DFU mode by holding the reset button while power-cycling. Then copy devzone.nordicsemi.com/.../6888.J_2D00_Link-OB_2D00_SAM3U128_2D00_V2_2D00_NordicSemi-170724.bin onto it , wait a bit and power-cycle again. Does it change anything with any of the two DKs?

RE: Noise from power profiler analysis

Ripitchip00 — Tue, 23 Feb 2021 10:15:31 GMT

Hello,

Thank you for your answer.

[quote userid="7377" url="~/f/nordic-q-a/71824/noise-from-power-profiler-analysis/295577#295577"] I assume you are using the first generation PPK and not PPK2?[/quote]

Yes it's the first generation PPK.

1st problem :

[quote userid="7377" url="~/f/nordic-q-a/71824/noise-from-power-profiler-analysis/295577#295577"]Are you trying to program the nRF on the DK or the nRF on the power profiler in this case (depending on the COM switch position)[/quote]

I'm trying to program the nRF on the DK. When I'm trying to flash, the power profiler isn't set on the DK, it's removed. I only have a DK with the jumper.

[quote userid="7377" url="~/f/nordic-q-a/71824/noise-from-power-profiler-analysis/295577#295577"]I suspect there could be an issue with the communication between the debugger on the DK and the nRF being programmed[/quote]

Is there a way to repair it ?

2nd problem :

[quote userid="7377" url="~/f/nordic-q-a/71824/noise-from-power-profiler-analysis/295577#295577"]Could it be that you accidentally programed the nRF on the DK (which is the DUT here?) with the PPK firmware?[/quote]

Well, here is the procedure I followed :

Remove the power profiler from any nRF
Setup the jumper on the nRF with cut SB40
Flash the beacon program, verify with nRF connect App that we really have a beacon device
Turn off the nRF, setup the power profiler on the nRF, remove the jumper, turn on
Open the Power Profiler app, select device. It doesn't ask to flash so I suppose it's ok ?
The first result was this, then I closed and reopened the Power profiler app and had only noise like the image in the original post.

For the sake of the experiment, I tried to setup the power profiler on the nRF that I can't flash again. I have the right Power Profiler output.

3rd problem :

[quote userid="7377" url="~/f/nordic-q-a/71824/noise-from-power-profiler-analysis/295577#295577"]You are covering 7 seconds here, so if there is a lot changes in current consumption that would be squashed together and look like a big blue square.[/quote]

Yes you are right but if I zoom in, I just have line going from down to up, there is no sense. And this blue square would be followed by a straight line.
I wanted to be able to flash the first device to see once again how the Power Profiler sees the mesh at the beginning as it's normal to have a lot of packets sending and receiving before and during provisioning but it's certainly not a blue square :)

I just was wondering if the change of device could impact the measurements, dunno.

Best regards

RE: Noise from power profiler analysis

Einar Thorsrud — Mon, 22 Feb 2021 13:05:16 GMT

Hi,

I assume you are using the first generation PPK and not PPK2?

[quote user=""]1st problem : I had one device with which I could use the power profiler correctly. Unfortunately I'm not able to flash a program on it. [/quote]

Are you trying to program the nRF on the DK or the nRF on the power profiler in this case (depending on the COM switch position) Based on the information in the 2nd question that this works with another DK, and the error message I suspect there could be an issue with the communication between the debugger on the DK and the nRF being programmed. If you are trying to program the PPK, then it could be an issue with the headers connecting the two boards. Perhaps some modifications or hard treatment has caused a bad connection or similar?

[quote user=""]2nd problem : I tried to use another nRF52840 with the power profiler. I cut the SB40. The problem is that I seem to get wrong measurements.[/quote]

It is a bit interesting that you get seemingly correct measurements with the other DK, which you have issue programming. Could it be that you accidentally programed the nRF on the DK (which is the DUT here?) with the PPK firmware? That will not have the current consumption pattern you expect to see.

[quote user=""]3rd problem : I tried to measure the power consumption of the sparkfun nRF52840 Mini as DUT and using the power profiler. When measuring the beacon app, everything is working great, so I'm able to set up everything correctly. But then measuring a mesh network application, I only see a blue square, or a straight line. Why is that ? [/quote]

You are covering 7 seconds here, so if there is a lot changes in current consumption that would be squashed together and look like a big blue square. It would not be possible to read anything from this plot. I suggest you look at a much smaller time window.

Einar