PPK time problem

RE: PPK time problem

Krzysztof Rosinski — Wed, 16 Nov 2016 11:53:22 GMT

I was testing an external device, tired this with both J-Link Lite and nRF52 DK (PCA10040) and had the same results. Today a trigger definitely stopped. Switch settings was as follows:

DUT select: External Power select: Reg. COM: DK/EXT

J-Link was connected directly to USB port on my PC, here are its stats:

RE: PPK time problem

wlgrd — Wed, 16 Nov 2016 11:47:04 GMT

Okay. This also sounds like you have the trigger running or for some reason are using a lot of resources on your computer and the J-Link connection is not able to empty it's buffers fast enough. Which DK or external debugger are you using? I will try to recreate it here as well.

RE: PPK time problem

Krzysztof Rosinski — Wed, 16 Nov 2016 10:45:15 GMT

Thanks for reply, I thought I had a trigger stopped but I'm not fully sure at the moment.

I've tried repeat this problem today and I couldn't. However today when I try to stop average scanning, it takes couple more seconds for graph to stop scrolling. It is quite hard to stop scrolling at a certain event, need to stop it in advance. I think yesterday graph stopped instantaneously.

I'll let you know if I'll be able to repeat this problem again.

RE: PPK time problem

wlgrd — Wed, 16 Nov 2016 10:15:29 GMT

The timing should be accurate to milliseconds, and the average current consumption of the whole window will be incorrect in your case. The instantanious current consumption numbers will still be correct.

These timing issues may happen if, for instance in this case, the trigger window is continously firing at say 2.5mA. The throughput capacity will be reached quite fast and this may cause lost packets or timing errors in the average window. Try to turn off the trigger while doing this measurement and see if that works. The User Guide states that it is recommended to not use the trigger window if not needed due to this.

RE: PPK time problem

wlgrd — Wed, 16 Nov 2016 10:08:34 GMT

Does your trigger run while doing this? If so, try to stop the trigger window and do the same measurement and report back.