NVMC Controller never gets ready when trying to flash nrf52840 custom board

RE: NVMC Controller never gets ready when trying to flash nrf52840 custom board

Sigurd Hellesvik — Wed, 03 Dec 2025 15:23:47 GMT

The first thing that comes to mind is that perhaps the debugging interface is not connected properly on the faulty device. For example a bad soldering.

Could you take oscilloscope readings from the SWD lines of both the working PCB and the faulty one, so we can compare them?

RE: NVMC Controller never gets ready when trying to flash nrf52840 custom board

ubimiles — Tue, 02 Dec 2025 14:13:02 GMT

Hi Sigurd,
yes they are indeed custom boards,
I am using a SEGGER JLink Base,
I have tried powering them on in both normal voltage and high voltage mode (~3.6V/~5.5V)

I do have two boards,
each with two nrf52840 chips
nrf52840-QIAA-T and nrf52840-CKAA-R

the two nrf52840-QIAA chips are behaving as expected
one of the two CKAA chips is erroring out with the NVMC error

RE: NVMC Controller never gets ready when trying to flash nrf52840 custom board

Sigurd Hellesvik — Tue, 02 Dec 2025 13:49:03 GMT

Hi,

These are custom boards right?
What do you use to program them?

What voltage are they powered by?

Regards,
Sigurd Hellesvik