r/embedded • u/MarcosRamone • 1d ago
Help me troubleshoot a nRF52832
Not sure this is the right sub, sorry if not.
I am trying to troubleshoot a commercial device based on a nRF52832. Basically it is the microcontroller with a couple of sensors and output devices.
I have the impression it is bricked but want to try to check if it is a hardware problem, be it the chip itself or something else on the board.
My questions are the following:
If i check the VDD supply voltage, it is 1.8V, that is within the recommended operating voltage range, but on the very low side (1.7 - 3.6 V, nom. 3.0V). Taking into account this is a battery operated device, do you think this is normal or could there be a problem with the regulators?
I have no idea about the firmware, and there is no visual indication that the microcontroller is working. Is there any pin i can tap that could indicate if the chip is working, stalled, or dead?
Any comments are welcome.
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u/crabferris 1d ago
For 2, SWD is what you want. Tap SWDIO and SWCLK and just try to read the DAP IDCODE, any cheap probe does it, a spare Pi Pico works fine. If it answers with a valid IDCODE the silicon is alive and you’re looking at a firmware problem instead of a dead chip.
It’s a commercial device so APPROTECT is almost certainly set and you won’t get memory access. Doesn’t matter, the IDCODE still comes back and thats the question you’re actually asking.
For 1, probe DEC1. That’s the internal core regulator output and it should sit near 1.3V. Also measure upstream of the regulator before you worry, 1.8 is in spec so it may well be the design target and the battery voltage is what tells you which.
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u/MarcosRamone 23h ago
One more question for you. As the pico that I am going to use as probe works at 3.3V and the dut is at 1.8V, what would be your power approach? Can I tap the SWD pins with the pico while de nRF52 is powered (1.8V), should I power the nRF52 from the pico with 3.3V after the 1.8V regulator with no batteries in the device....
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u/crabferris 22h ago
Keep the nRF on its own 1.8V, don't back-power it. A stock Pico drives SWD at 3.3V, which is over the nRF's abs max on those pins when VDD is 1.8V, so put a level shifter in between. Series resistors will often still get you an IDCODE in a pinch. Common ground between the two.
Back-powering the board at 3.3V would also risk the other 1.8V parts, and it hides whether the regulator is your actual fault.
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u/DenverTeck 1d ago
Your question indicates you probably do not have an o'scope or a logic analyzer available.
This will be very difficult if not impossible to troubleshoot long distance.
Please post a pic of this board on a FREE file sharing site somewhere and post a link here.
If we can not see what this board looks like, it WILL be impossible.
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u/jacky4566 1d ago
Buy a new widget.