I am unable to debug a Fanstel BM840 nRF52840 based simple custom board using a nRF52840 DK. I believe the custom board is basically ok: Before flashing my application onto it, powering it would run a Fanstel BT test program visible over the air. The custom board is a Fanstel BM840 with connectors and nothing else.
Development context:
- Using nRF Connect for VS Code, version 2025.5.152
- nRF Connect SDK 3.0.1
- nRF Connect Toolchain 3.0.1
- nRF52840 DK is connected to the Custom Board through the P20 connector as follows:
- P20.VDDnRF' to Custom Board VDD
- P20.VTG to Custom Board VDD
- P20.SWDIO to Custom Board SWDIO
- P20.SWDCLK to Custom Board SWCLK
- P20.RESET to Custom Board RST
- P20.GND_DETECT to Custom Board GND
- P4.GND to Custom Board GND
- Custom Board support defined through nRF Connect for VS Code following guidelines discussed in the Nordic video "Adding Custom Board Support in nRF Connect SDK
- Flashing the Custom Board seems successful:
-- runners.nrfjprog: Flashing file: C:\nordic\SlotCars\Car\build_4\merged.hex
[ #################### ] 5.058s | Erase file - Done erasing
[ #################### ] 2.100s | Program file - Done programming
[ #################### ] 2.061s | Verify file - Done verifying
Applying system reset.
Run.
-- runners.nrfjprog: Board with serial number 683268243 flashed successfully.
The DEBUG CONSOLE shows the following:
JLinkGDBServerCL: SEGGER J-Link GDB Server V8.18 Command Line Version
JLinkGDBServerCL:
JLinkGDBServerCL: JLinkARM.dll V8.18 (DLL compiled Mar 5 2025 14:42:43)
JLinkGDBServerCL:
JLinkGDBServerCL: -----GDB Server start settings-----
JLinkGDBServerCL: GDBInit file: none
JLinkGDBServerCL: GDB Server Listening port: 51896
JLinkGDBServerCL: SWO raw output listening port: 2332
JLinkGDBServerCL: Terminal I/O port: 2333
JLinkGDBServerCL: Accept remote connection: localhost only
JLinkGDBServerCL: Generate logfile: off
JLinkGDBServerCL: Verify download: off
JLinkGDBServerCL: Init regs on start: off
JLinkGDBServerCL: Silent mode: on
JLinkGDBServerCL: Single run mode: on
JLinkGDBServerCL: Target connection timeout: 0 ms
JLinkGDBServerCL: ------J-Link related settings------
JLinkGDBServerCL: J-Link Host interface: USB
JLinkGDBServerCL: J-Link script: none
JLinkGDBServerCL: J-Link settings file: none
JLinkGDBServerCL: ------Target related settings------
JLinkGDBServerCL: Target device: nRF52840_xxAA
JLinkGDBServerCL: Target device parameters: none
JLinkGDBServerCL: Target interface: SWD
JLinkGDBServerCL: Target interface speed: 4000kHz
JLinkGDBServerCL: Target endian: little
JLinkGDBServerCL:
=thread-group-added,id="i1"
=cmd-param-changed,param="pagination",value="off"
0x0000a7de in sym_WVJLOWUIPBC2HDDMNEWOD4POANUBUKS6OYFXDSA ()
That is all that happens. The debugger never starts up on main(). No register contents are visible.
Any idea of what to do next would be greatly appreciated.
Thank you,
Ken
