0xDEADBEEE when flashing and debugging a custom 52840 board

[August Fricking]

Hi, 

I'm having some trouble running example code on my custom board with the nrf52840 SoC. Im using nRF Connect for VSC on Windows and can flash the simple "blinky" program to a DK without any trouble. But when flashing the same code to my custom board the debugger says:

"Thread 2 received signal SIGTRAP, Trace/breakpoint trap.

0xdeadbeee in ?? ()"

This error seems to occur before even entering the main loop. Any suggestions of what might be wrong?

[Priyanka]

Hi,

Is the DK that you tried on an nRF52840DK? 

Could you attach what you see in the Problems /Output window in VS Code?

What version of nRF Connect SDK are you using?

Best Regards,

Priyanka

[August Fricking]

Yes it is, sorry for not specifying that.

Of course;

the problems window is empty.

Im using v2.1.0 of the nRF Connect SDK.

[Priyanka]

Hi August,

Could you try to read the RESETREAS register in order to check if the RESET pin was enabled somehow?

-Priyanka

[August Fricking]

Seems like it might be getting reset by the pin if I'm interpreting this correctly. The thing is I have to reset the CPU to every time I want to read/write to the chip. The first result was after a reset, and the second ("Failed to read memories") was after I had erased and flashed the device. So it seems like the device is getting read/write protected after flashing it, which maybe is the expected outcome? And if that is the case, then the RESET pin should read 0 since it is read protected right?

I'm issuing the reset command via J-Link Commander.

[Priyanka]

Hi August,

What is your chip revision? 

All new chips have the protection on by default

So this read/write protection after flashing is an expected behaviour.

-Priyanka

[August Fricking]

Hi, 

It is chip revision 2. 

[Priyanka]

Okay, but only for revision 3 is the approtect enabled by default. Could you try to reset using the nrfjprog --reset and then try to read again?

-Priyanka

[August Fricking]

I was only able to run the "nrfjprog --reset" command if I first reset the CPU via J-Link commander and followed it up with the commands seen in the picture. Otherwise, "failed to read device memories" was the only output I got. 

[Priyanka]

Hi,

I will check internally and get back to you soon.

-Priyanka

[August Fricking]

Alright, thank you!
Let me know if you need any additional information.

[Gray L]

Hi Priyanka I'm having the same issue on a nrf52840 on a custom board. Was there any resolution here?

[August Fricking]

This was a while ago and I don't recall the solution to this specific problem.

But the biggest error in my case was that the custom board didn't have a 32 kHz crystal while the devkit did. But like I said, I'm not sure if that is related at all to this though.