Error when programming a custom board using nRF52-DK

[Artem Efremov]

Dear colleagues,

I am trying to erase / program the custom board ( with nRF52832 SoC installed) using nRF52-DK. The setup looks like that:

nRF52-DK Custom / External Board

VDD ------+-------------> VDD

VTG ----+/

GND ------------------------> GND

GND DETECT -----/

SWD IO -----------------> SWD IO

SWD CLK ----------------> SWD CLK

As the picture shows, the custom board nRF52-DK is powered from USB, and the custom board is powered from the nRF52-DK. The voltage on VDD (P20), VTG (P20), and external board is 2.86V. The voltage on SWDCLC and SWDIO (P20) is 2.63V.

When I try to use nRFGO, the program just reloads whenever I click on motherboard's name. When I try to use nrfjprog, it shows the following error in log file:

When I try to connect using JLinkExe, it shows the error:

The schematic of the custom board is represented on the picture bellow:

I will appreciate any help!

P.S. programming the nRF52-DK (without custom board) works just fine.

UPDATE: when I power the custom board from the external power supply:

1. custom board and DK not connected:

• voltage at DK: VDD - 2.88V, VTG - 0, SWDIO-2.65V, SWDCLC-2.65V
• voltage at custom board: VDD - 3.26V, SWDIO-3.21V, SWDCLC-0V

2. custom board and DK are connected

nRF52-DK Custom / External Board

VTG ------+-------------> VDD

GND ------------------------> GND

GND DETECT -----/

SWD IO -----------------> SWD IO

SWD CLK ----------------> SWD CLK

• VTG - 3.26V, SWDIO: 3.30V, SWDCLC - 0.52V on both
• if I disconnect SWDCLCs, when SWDCLC at DK is 3.56V, at custom board - 0V
• if I disconnect SWDIOS, when SWDIO at DK is 3.56V, at custom board - 3.21V

The setup was tested with another nRF52-DK and it also did not work, so DK is not the problem.

The closer photo of how the chip is mounted is attached: DSC00364.png

[endnode]

Hi, it's not really visible from your photo but I guess you have VTG and GND DETECT PINs wrongly connected on nRF52 DK P20 header. VTG must be linked to 3V3 (ideally by short to some VDD PIN on nRF52 because you are powering everything through it) and GND DETECT should be grounded (again ideally to some GND PIN on nRF52). See scheme in this Q&A and alternatively other Q&As like this one when debugging flashing through P19 and P20 of nRF5x DK boards.

[Artem Efremov]

Thank you for your comment! But the connection scheme is correct (is is exactly the same as in the question which you referred): VTG is linked to VDD on nRF52, and GND Detect is linked to GND on nRF52 . It may look wrong due to colors of the wires, sorry about that.

[endnode]

I see. I was having similar errors due to bad wiring, are you sure all these jump wires have good contacts? Also good test that J-Link is working well is to remove short between VDD and VTG, it should then target internal nRF5x chip on the board (and typically flash it successfully if it's correct family).

[Artem Efremov]

yes, we double-checked everything one hundred times before posting to the forum, but, unfortunately, all jump wires have good contacts, so the problems is somewhere else. I have just removed the short between VDD and VTG, and the nRF52 DK was flashed successfully.

[endnode]

OK, almost running out of ideas. If usual nrfjprog --recover -c %SPEED% --family %NRFFAMILY% --log doesn't help in NRFTOOLS v9.4.0 then I once had more luck with recovery through nRFgo Studio (surprisingly). Note that I run all the tools on Win7, never on Linux/MAC (even with Win7 VM on these systems). You say that nRFgo Studio fails whenever you connect the board to the machine and try to select it, is that on Windows? If so then it more indicates HW (power) problem than anything else...