Unable to recover nrf52832 after writing into APPROTECT register

RE: Unable to recover nrf52832 after writing into APPROTECT register

Simen August Tinderholt — Tue, 16 Jan 2018 09:07:02 GMT

Hi, Are you able to do this test? It would give us some valuable information so we can find out exactly where it fails.

RE: Unable to recover nrf52832 after writing into APPROTECT register

Simen August Tinderholt — Fri, 12 Jan 2018 09:25:45 GMT

Hi, could you do the following and attach both the resulting nRFJProg and Segger log files?

Open J-Link Commander.
Right click the small green J-Link icon in the windows task bar and press Open.
Under Settings->Log File, tick the "Override" box, and specify a log file path for the Segger log.
Close Control Panel, but leave J-Link Commander open.
Run nrfjprog -f NRF52 --recover --log

After you're finished, you may want to the log file setting as Segger will remember it between sessions. This can be done by removing the "Override" check mark. in the Control panel.

RE: Unable to recover nrf52832 after writing into APPROTECT register

Simen August Tinderholt — Thu, 11 Jan 2018 07:50:22 GMT

Ok, and both the J-Link pro and the J-Link edu fail? That should at least rule out incompatability.

RE: Unable to recover nrf52832 after writing into APPROTECT register

sreehari410 — Wed, 10 Jan 2018 15:19:42 GMT

I don't have a DK.

RE: Unable to recover nrf52832 after writing into APPROTECT register

David García Polo — Wed, 10 Jan 2018 13:55:13 GMT

Do you have a DK? Why dont you use the debugger in the DK in that case?

RE: Unable to recover nrf52832 after writing into APPROTECT register

sreehari410 — Wed, 10 Jan 2018 13:53:29 GMT

I am using the JLink Pro with dll version V6.20i

RE: Unable to recover nrf52832 after writing into APPROTECT register

David García Polo — Wed, 10 Jan 2018 12:46:02 GMT

What segger debug probe are you using? What segger dll version are you using? What device are you using?

I have never seen "Not supported by current CPU + target interface combination." error message in the log.

RE: Unable to recover nrf52832 after writing into APPROTECT register

endnode — Fri, 29 Dec 2017 14:57:39 GMT

And one more btw.: it's kind of logical to enforce chip read-back protection at the start-up if it is not done through the external SWD programmer before even running the FW for the first time. However your code snippet suggests that you run some code including enabling BLE stack, then you disable it again because you want to write to UICR (it could be done through SD API as well - at least I believe so) and then you enable the stack again. Why so complicated????

RE: Unable to recover nrf52832 after writing into APPROTECT register

endnode — Fri, 29 Dec 2017 14:55:18 GMT

First of all you shouldn't write into such register blindly in your code. It almost looks like at certain point you write into it on every occasion! It would be much better to just read the value first and write into it only if the value isn't the one you need.

To the issue itself: what SEGGER J-Link probe do you use? Is it running the latest SEGGER J-Link firmware and the same for SEGGER J-Link SW pack on our PC? Could you try to recover the chip through nRFgo Studio instead of nrfjprog?