Modems exhibiting different behavior

Keysight 34450A

I have no experience with such high speed multimeter. But “190 readings/sec” is much slower then I run my power profiler. So, not sure, if that value fits the reality. A simple Nordic Power Profiler Kit II is quite inexpensive (around 100 Euro). There are a couple of power charts of the nRF9160 in the web, I also published some one, see zephyr-coaps-client / power-consumption

Would that be PSM sleep?

The modem has several function to save energy (mainly by switching between the 3 states faster). If you switch the modem off/on (CFUN=0/CFUN=1) the switching on takes some more energy. If you network supports PSM, then the device will be able to enter the sleepmode and wakeup faster (and with less energy). In general, people report, that the difference is quite large. In my own experience with the nRF9160 both works very close to each other.
If you want to know more about the “state” the modem is actually using, there are events which indicates RRC active, RRC ide, sleeping on and sleeping off.

Nordic’s power profiler is great for budget projects but the Joulescope, in my experience, has a significantly higher sample rate which is useful for catching transients

JS220

2 million times per second with 300 kHz bandwidth.

PPK II

100 ksps sampling rate

Anyway, a PPK II does a better job than a high speed multimeter with 190 sps.
It would be very interesting, if the higher sample rate really does an even better job. Did you made some test comparing that?
In my experience I use even less samples. I have even tested an “on device” approach with an INA233 at about 1ksps, which results also in pretty good values (about 10% delta to PPK II, but measured “continuously in the wild”).

AchimKraus Anyway, a PPK II does a better job than a high speed multimeter with 190 sps.

Yes!

AchimKraus It would be very interesting, if the higher sample rate really does an even better job. Did you made some test comparing that?

It sure does. I’ve done side by side tests because one of my customers was saying the current draw was higher than I saw on the PPKII. Ran the test on the Joulescope and sure enough he was right!

piotr337 Any thought on what could be causing an issue with not being able to program a board?

Did you have the serial monitor open at the same time. That will cause issues with bootloader usage. Is the blue LED solid when running the load command?

SilasValera what firmware are you running? Still your application firmware? What are the values if you run at 3.5VDC on VBAT? I assume the first numbers are the identifiers for the boards?

piotr337 I ran a quick test with a different board, and that worked, then I switched back the “bad” board and it fails.

Gotcha thanks for checking. Are you strictly using the bootloader only? Is it possible you may have overwritten the bootloader?

I believe the default configuration for the newer boards is reverse the polarity that it should be for >= v5. Meaning that if you initialize the LED without those changes it’s on by default. i.e. that may not be the bootloader running but another application

Yea if you’re only using the bootloader via the onboard USB-C then that’s likely not it. Has that board been modified at all? (Headers soldered, etc)

this board has had headers soldered on it

Did you clean the headers? That was something, which costs me several days and is so far the only cause I found when I get irritating different behavior between nRf9160 feathers v5.

Just to make sure, it’s not something in the firmware, did you try the system OFF mode?

#include <modem/lte_lc.h>
void main(void)
{
 lte_lc_power_off();
 k_sleep(K_MSEC(1000));
 NRF_REGULATORS->SYSTEMOFF = 1;
}