nRF52840 DK cannot run Direct Test Mode APP in nRF connect for Desktop

[chenzhao]

Hello

I got a nRF52840 DK and try to use Direct Test Mode APP (v2.0.3) in the nRF Connect for Desktop (v3.12.0).

However, it always says "Can not communicate with device. Make sure it is not in use by another application and it has a Direct Test Mode compatible firmware".

It seems that Uploading image through Jlink process is always 0%.

Does that means I need to connect the Jlink to the nRF52840 DK, apart from the micro-USB connection? 

Hope someone could help answer this question.

Many thanks for your support. 

Logs

=====================================================================================================

19:22:50.099

Validating firmware for device with s/n 001050238327

19:22:54.258

{"chip_erase_mode":"ERASE_ALL","qspi_erase_mode":"ERASE_NONE","reset":"RESET_NONE","verify":"VERIFY_NONE"} 100%

19:22:54.258

Uploading image through JLink: 0%

19:22:54.475

Device programming completed.

19:22:54.479

Device selected successfully

======================================================================================================

Error message

Hardware picture

[Amanda Hsieh]

Hi, 

Please run "nrfjprog --recover" before programming the board. 

Regards,
Amanda H.

[chenzhao]

Hi Amanda 

Many thanks for your feedback. I have downloaded the nRF command line tool using the download link below.

https://www.nordicsemi.com/Products/Development-tools/nrf-command-line-tools/download#infotabs

And connect the Jlink to the "Debug in" port in the middle of nRF 52840 DK board and try to run "nrfjprog --recover"  and it works.

command line log

======================================
D:\>nrfjprog --recover
Recovering device. This operation might take 30s.
Erasing user code and UICR flash areas.
Writing image to disable ap protect.
=======================================

Then I can successfully uses Direct Test Mode APP, as shown below.

==============================================================

09:46:55.555

Using nrf-device-lib-js version: 0.4.13

09:46:55.555

Using nrf-device-lib version: 0.12.8

09:46:55.556

Using nrfjprog DLL version: 10.16.0

09:46:55.556

Using JLink version: JLink_V7.80c

09:46:55.611

Installed JLink version does not match the provided version (V7.66a)

09:47:01.020

Validating firmware for device with s/n 001050238327

09:47:05.554

{"chip_erase_mode":"ERASE_ALL","qspi_erase_mode":"ERASE_NONE","reset":"RESET_NONE","verify":"VERIFY_NONE"} 100%

09:47:05.554

Uploading image through JLink: 0%

09:47:05.924

Uploading image through JLink: 100%

09:47:06.109

Device programming completed.

09:47:07.350

Device selected successfully

09:47:12.518

Running device setup

================================================================

May I know what is the purpose of "nrfjprog --recover" ? Is it to disable the AP protect? 

Looking forward to your reply. Thanks.

Hardware setup

[Amanda Hsieh]

Hi, 

The DK is v.3.0.0 which comes with the access port protection enabled. It needs to unlock (nrfjprog --recover) before programming. 

See IN141 Informational Notice v1.1 and Working with the nRF52 Series' improved APPROTECT. 

-Amanda H.