Problem bringing up a custom board (cant see board outside of bootloader mode)

[hmahdi]

I have designed a custom board for the nrf52840 and upon testing it in the nrf connect sdk (using a JLink), I can only see the board when it's in bootloader mode. When it's in normal operation, the debugger does not show it. 

Additionally, it does not appear as a USB device although I enabled USB CDC. In fact, I kept the configuration pretty much similar to the nrf52840 dongle when I defined the custom board on the nrf connect sdk.

Has anyone run into a similar issue? Are there any guidelines for how to debug such a problem?

[hmahdi]

I found this person saying the reset pin could solve the problem. I will try to connect the reset to the jlink:

https://devzone.nordicsemi.com/f/nordic-q-a/82547/cant-program-custom-board

I'll keep you posted. Meanwhile, if it seems anything is wrong with the configuration i posted please let me know!

[hmahdi]

Unfortunately, connecting the reset pin did not change the behaviour.

[Einar Thorsrud]

Hi,

Can you backtrack and continue to test with the Blinky example first, and use a board based on nrf452840dk_nrf52840 (not the dongle!)? Even if you have a dongle form factor, the nrf452840dk_nrf52840 is likely a better starting point as it has no fuzz. Then it should be enough to only change the LED pin to get the blinky sample working.

[hmahdi]

Thanks for your patience we me. I remade the board with the vscode extension this time (not starting from the dk or the dongle) to back track even more.

It seems this is definetly on the right track, because I no longer get a SIGTRAP when running debug (but of course I cant actually debug because jlink still only sees the board when the reset switch is flipped).

Here is a screenshot of when I run debug in reset mode: 

P.S. I did what you suggested by essentially only adding the one pin needed by the blinky program for the sake of simplicity.

[hmahdi]

I have some more information about the error. When I use the "recover board" feature in vscode, I can see the board when not in reset mode as long as I have not downloaded any code to the board. So what I did, I clicked debug on this clean board, and I got a new error message:

Program
 received signal SIGTRAP, Trace/breakpoint trap.
0xdeadbeee in ?? ()
Debug-14: Enqueuing {"command":"disassemble","arguments":{"memoryReference":"0xdeadbeee","offset":0,"instructionOffset":-200,"instructionCount":400,"resolveSymbols":true},"type":"request","seq":14}
Note: We detected the following memory regions as valid using gdb "info mem" and "objdump -h"
    This information is used to adjust bounds only when normal disassembly fails.
================================================================================
  Using following memory regions for disassembly
================================================================================
      Size   VMA Beg   VMA End   LMA Beg   LMA End  Attributes
================================================================================
  Unfortunately, No memory information from gdb (or gdb-server). Will try to manage without
  ------------------------------------------------------------------------------
  0000503c  00000000  0000503c  --------  --------  (.sec1) contents alloc load
================================================================================
Debug-14: Dequeuing...
Debug: Gdb command: -data-disassemble -s 0xdeadbbce -e 0xdeadc20e -- 5     1600 bytes 
Error: GDB failed: Cannot access memory at address 0xdeadbbce (from data-disassemble -s 0xdeadbbce -e 0xdeadc20e -- 5)