Manual reflash of nRF 52840 Dongle - Failed to power up DAP

[TE_Leo]

I'm trying to reflash the dongle with the "connectivity firmware". I previously used nRF Connect to do that, but with the latest version, the bootloader got somehow corrupted (it proposed to update the bootloader, i clicked no, then the device was no longer visible in Windows). The device is not even shown in device manager, so i suppose that the bootloader is somehow corrupted, and the USB connectivity is completly broken.

So instead of USB SDFU, i'm using a Jlink probe to reflash through SWD. 

The following error message appears : 

CLCK, IO, Vtref and GND are cabled.

Best regards,

[Turbo J]

Connect the RESET line too and let nrfjprog "recover" the device.

[TE_Leo]

Thanks for your answer.

I used nrfjprog and here's the output of the command "nrfjprog --recover -f NRF52" : 

With or without the reset line connected. By the way, to re-flash the reset line is not needed, right ?

[Einar Thorsrud]

Hi,

Which type of debugger are you using? If you are using something like the nRF DKs as debugger those are fixed to 3V, and that can be problematic if you have done a full erase of a donge, as that will also erase the high voltage regulator configuration in the UICR, making it use 1.8V as VDD, making the SWD signal voltage also 1.8 V. If that is the case, please refer to the Recover after an accidental UICR erase section in the nRF52840 Dongle Programming Tutorial.

[TE_Leo]

I'm powering up the Dongle through an external alimentation with 5V on VBUS.
I'm using Jlink EDU https://www.segger.com/products/debug-probes/j-link/models/j-link-edu/ and i connected its VTREF to the dongle VDD_OUT

Is the problem related to this debug probe ? Like mentionned inside the tutorial you linked, the probe does not adapt its SWD voltage level ?

[TE_Leo]

You right the VDD OUT is 1.8V so i guess the IUCR has been erased.

Iborrowed a Jlink PRO from a colleague, and the output of the same command i posted above is as follow : 

[Einar Thorsrud]

Hi,

The dongle is always powered by 5V (USB VBUS), but internally the output of the high voltage regulator REG0 is used. And after a full chip erase this will be 1.8 V. And the J-Link EDU only support 3.3V (though 3V will work fine). 1.8 V will not though. So you either need to power the dongle externally while recovering (power it with 3V) or use another debugger.

[TE_Leo]

Ok after using the jlink pro, the result are the same, i've got timeout error. Is there any specfic configuration to enable on the probe ? Or is it plug and play. 
Error msg is the same on nrf COnnect programmer "TIME_OUT"

[Einar Thorsrud]

Hi,

TE_Leo said:

Is there any specfic configuration to enable on the probe ? Or is it plug and play. 

You can configure VDD manually, but if you connect VDD (which I suspect is 1.8V on your dongle at this point) to the J-Link, it should automatically juse that voltage for SWD. For this you can use the VDD OUT connection on the dongle (see the hardware drawing).

Can you run nrfjprog with debug logging (--log) and upload the log here? I suspect there are still problems communicating with the nRF via SWD as you get -21, but perhaps the log will tell us more.