Trouble getting started with Zephyr

strooom · October 5, 2025, 3:54pm

I’m exploring Zephyr. I have a supported board (SeeedStudio LoRa E5 Dev Board) and I tried the blinky and hello world examples. (using an ST-Link debug probe)

I am able to build the applications
I am able to download the applications

But no LED is blinking and nothing is sent on any UART

Then I tried to debug.
I’ve set

CONFIG_THREAD_MONITOR=y
CONFIG_DEBUG_THREAD_INFO=y

in prj.conf. The debugger is connecting, but the code does not even seem to reach the first breakpoint at main()

This is the output of the debug console

Reading symbols from C:\Users\pasca\Documents\Projects\Software\Zephyr000\.pio\build\lora_e5_dev_board\firmware.elf...
Warning: 'set target-async', an alias for the command 'set mi-async', is deprecated.
Use 'set mi-async'.

PlatformIO Unified Debugger -> https://bit.ly/pio-debug
PlatformIO: debug_tool = stlink
PlatformIO: Initializing remote target...
xPack Open On-Chip Debugger 0.12.0-01004-g9ea7f3d64-dirty (2023-01-30-15:04)
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
hla_swd
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
none separate

Info : tcl server disabled
Info : telnet server disabled
Info : clock speed 500 kHz
Info : STLINK V3J14M5 (API v3) VID:PID 0483:374E
Info : Target voltage: 3.313754
Info : [stm32wlx.cpu0] Cortex-M4 r0p1 processor detected
Info : [stm32wlx.cpu0] target has 6 breakpoints, 4 watchpoints
Info : starting gdb server for stm32wlx.cpu0 on pipe
Info : accepting 'gdb' connection from pipe
[stm32wlx.cpu0] halted due to debug-request, current mode: Thread 
xPSR: 0x41000000 pc: 0x1fff23f4 msp: 0x200014e8
Info : device idcode = 0x10016497 (STM32WLE/WL5x - Rev 'unknown' : 0x1001)
Info : RDP level 0 (0xAA)
Info : flash size = 256 KiB
Info : flash mode : single-bank
Info : device idcode = 0x10016497 (STM32WLE/WL5x - Rev 'unknown' : 0x1001)
Info : RDP level 0 (0xAA)
Info : OTP size is 1024 bytes, base address is 0x1fff7000
Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1044 ms). Workaround: increase "set remotetimeout" in GDB
0x1fff23f4 in ?? ()
2
Info : Unable to match requested speed 500 kHz, using 200 kHz
[stm32wlx.cpu0] halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x1fff2af4 msp: 0x20001500
2
Info : Unable to match requested speed 4000 kHz, using 3300 kHz
Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1028 ms). Workaround: increase "set remotetimeout" in GDB
Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1014 ms). Workaround: increase "set remotetimeout" in GDB
Loading section rom_start, size 0x138 lma 0x8000000
Loading section text, size 0x4dac lma 0x8000138
Loading section .ARM.exidx, size 0x8 lma 0x8004ee4
Loading section initlevel, size 0x80 lma 0x8004eec
Loading section device_area, size 0x180 lma 0x8004f6c
Loading section sw_isr_table, size 0x1f0 lma 0x80050ec
Loading section gpio_driver_api_area, size 0x24 lma 0x80052dc
Loading section reset_driver_api_area, size 0x10 lma 0x8005300
Loading section clock_control_driver_api_area, size 0x1c lma 0x8005310
Loading section regulator_driver_api_area, size 0x3c lma 0x800532c
Loading section uart_driver_api_area, size 0x14 lma 0x8005368
Loading section zephyr_dbg_info, size 0x44 lma 0x800537c
Loading section rodata, size 0x44c lma 0x80053c0
Loading section datas, size 0x64 lma 0x800580c
Loading section device_states, size 0x18 lma 0x8005870
Loading section .last_section, size 0x4 lma 0x8005888
Info : Padding image section 0 at 0x0800588c with 4 bytes (bank write end alignment)
2
Info : Unable to match requested speed 500 kHz, using 200 kHz
[stm32wlx.cpu0] halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x1fff2af4 msp: 0x20001500
Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1028 ms). Workaround: increase "set remotetimeout" in GDB
Start address 0x080005a0, load size 22668
Transfer rate: 6 KB/sec, 1333 bytes/write.
2
Info : Unable to match requested speed 500 kHz, using 200 kHz
2
Unable to match requested speed 500 kHz, using 200 kHz
[stm32wlx.cpu0] halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x1fff2af4 msp: 0x20001500
[stm32wlx.cpu0] halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x1fff2af4 msp: 0x20001500
Temporary breakpoint 1 at 0x800016c: file src\main.c, line 24.
Note: automatically using hardware breakpoints for read-only addresses.
PlatformIO: Initialization completed
PlatformIO: Resume the execution to `debug_init_break = tbreak main`
PlatformIO: More configuration options -> https://bit.ly/pio-debug

the file .platformio\packages\framework-zephyr\arch\arm\core\cortex_m\reset.S is opened

When I pause program execution, I get

Program
 received signal SIGINT, Interrupt.
0x1fff27fe in ?? ()

Any ideas what’s going on and how to solve this ?

maxgerhardt · October 5, 2025, 4:03pm

Mhm, that’s just being in reserved memory..

If it would have been in teh “System Flash” section I would have said that maybe it’s in bootloader code and you should fiddle with the BOOT0 pin, but that doesn’t seem to be the case.

When you add

debug_init_break =

or

debug_init_break = b Reset_Handler

to the platformio.ini and start a debug session, does it halt in the first instruction of the Reset_Handler()?

You can strategically step through the code (or set breakpoints after long loops and let it run there) to see how far it gets into initialization before it crashes in some code.

maxgerhardt · October 5, 2025, 4:04pm

Also what’s the exact platformio.ini? This is using board = nucleo_wl55jc the regular latest ststm32 platform?

strooom · October 5, 2025, 4:26pm

This is platformio.ini, as generated by the project wizard - only added the last line to specify st-link as debug probe

[env:lora_e5_dev_board]
platform = ststm32
board = lora_e5_dev_board
framework = zephyr
debug_tool = stlink

strooom · October 5, 2025, 4:36pm

Mmm, after powercycling the board, it’s all working…

Anyway the tip about debug_init_break = b Reset_Handler is useful for the future…

Thank you Max !