Unable to recover NRF52832 with JLink after reset event

RE: Unable to recover NRF52832 with JLink after reset event

Sigurd — Mon, 08 Oct 2018 13:05:25 GMT

I don’t see anything wrong in the schematics.

Have you measured (using logic analyzer or oscilloscope) that the SWD signals are actually reaching all the way to the chip? I.e. that there are no bad wires or soldering?

Have you measured the amplitude of the SWD signals reaching the chip?

RE: Unable to recover NRF52832 with JLink after reset event

Expy — Wed, 03 Oct 2018 14:29:29 GMT

Thank for your feedback,

Yes, we connected the VTG and GND detectors.
The voltage on the reset pin is 3.65 measured.
The wiring of the SWG should be correct because we have already flashed the NRF a few times.

Our setup :

The only pin that we didn't connect is SWO (But we never used it before).

Our Jtag adapter :

RE: Unable to recover NRF52832 with JLink after reset event

Sigurd — Wed, 03 Oct 2018 08:42:57 GMT

Hi,

Have you connected VTG detect and GND detect?

What is the voltage on the reset pin(P0.21)?

Could you double check you wiring, and make sure that you have not e.g switched SWD IO AND SWD CLK.

Could you upload a picture of your setup that shows how the wires are connected?

RE: Unable to recover NRF52832 with JLink after reset event

Expy — Thu, 27 Sep 2018 08:41:34 GMT

Thanks, but i've already read it, and I know we can disabled Reset, but I've not found any information about a reconfiguration for SWD.

The Reset haven't been reconfigured. And yes the debugger connector was connected properly.

The 3.6V come from a regulator, and we use it because we have another component which required this voltage.

RE: Unable to recover NRF52832 with JLink after reset event

Turbo J — Wed, 26 Sep 2018 10:29:10 GMT

RTFM: SWD and Reset can be disabled in the UICR.

Did you remember to connect the target voltage properly to your Segger EDU?

The 3.6 Volts seems rather high - please don't connect an NRF5x directly to a Li-Ion or Li-Poly cell. These charge up to 4.2 Volts, which is above absolute maximum rating.

RE: Unable to recover NRF52832 with JLink after reset event

Expy — Tue, 25 Sep 2018 13:24:34 GMT

First, thank you for your support.
What do you mean by "reconfigure SWD" ? I didn't know that it was configurable.

I know that I need SWD, but it seems that the NRF52 not allow to use it. The connection between debugger and SWDIO/SWDCLK is good, but still, my JLink can't access.
I've already tried to force the reset pin but without success.

RE: Unable to recover NRF52832 with JLink after reset event

Turbo J — Tue, 25 Sep 2018 10:22:59 GMT

Did you reconfigure SWD or Reset pins?

Recovering requires at least SWD. There is a small timing window during power-up (or device reset) where recovery is possible.

You may need to play with target power (or reset if available) manually just before launching above nrfjprog command line.