RTT viewer or Segger message: CTRL-AP indicates that the device is secured (J-Link V6.88a Info)

[Bruno Saraiva]

Working in a Windows 64 environment with nRF Connect SDK v1.5.0. Target is a custom nRF5340 board connected through a nRF5340-PDK as a debugger, via USB.

I can no longer use RTT Viewer to connect to our target: any attempt to connect pops up a message saying CTRL-AP indicates that the device is secured... Do you want to unsecure the device?

Answering YES fully erases the target. Answering NO results in denied connection.

 

The same message is popping up when trying to run the debugger directly via Segger (the debugger works, but only after it fully erased the target and reuploaded the code).

This was not happening before, but we are unsure of what was changed to cause it and how to get around.

Regards

Bruno

[Vidar Berg]

Hi,

Please try using the attached hex files and see if you get the same result. This time, I built the sample with CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y, and the DCDC regulators are disabled in case your board does not have the optional DCDC inductors mounted.

Symbols to disable the DCDC regulators (must be applied to the app core build)

CONFIG_BOARD_ENABLE_DCDC_APP=n
CONFIG_BOARD_ENABLE_DCDC_NET=n
CONFIG_BOARD_ENABLE_DCDC_HV=n

nrfjprog commands to program the hex files

$ nrfjprog --coprocessor CP_NETWORK --program net.hex --recover --verify
$ nrfjprog --program app.hex --recover --verify -r

hex files

4370.app.hex

net.hex

[C.Thilo]

Hey Vidar 

very old post, but I face the same problem today.

Sadly I don't get, what the fix was. In your project, you just enabled logging for both cores and build a source which outputs every second something.

But how this fixes the SEGGER RTT problem, is not mentioned:

CTRL-AP indicates that the device is secured.
For debugger connection the device needs to be unsecured.
Note: Unsecuring will trigger a mass erase of the internal flash, SRAM and UICR of both the application and the network core.

Everytime I connect the RTT Viewer to the netcore (nRF5340_xxAA_NET) I get that message and the mass erase removes the fw, of course.

After that I need to recover flash to be able to get fw onto the cores.
But the recover flash secures the device again, so I can't get any logging from netcore at all.

Cheers
Thilo