Trying to debug my sample blink_led code on STM32L476 Nucleo-64 board but gdb can't connect to OpenOCD (connection drops almost instantly with error). I've read plenty of posts here and there but none of them helped. Tried adding commands to OpenOCD using -c but no change of behavior.
My code compiles both in Release and Debug config in Eclipse. I can flash the bin file using drag and drop (while the board has built-in STLink add-on) and looks the code runs perfectly on the board (LED blinks).
Cross compiling on Centos7 using the following versions:
As using eclipse didn't work I tried the command line,
(I'm not an experienced developer in this environment so I could not find any config file closer to my stm32l476 board than the stm32l4discovery.cfg, please let me know if there might be some issues using it)
./bin/openocd -f scripts/board/stm32l4discovery.cfg -c "init"
It starts,
GNU MCU Eclipse 64-bit Open On-Chip Debugger 0.10.0+dev-00462-gdd1d90111 (2019-01-18-11:37)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
adapter speed: 500 kHz
adapter_nsrst_delay: 100
none separate
srst_only separate srst_nogate srst_open_drain connect_deassert_srst
Info : clock speed 500 kHz
Info : STLINK V2J28M17 (API v2) VID:PID 0483:374B
Info : Target voltage: 3.244386
Info : stm32l4x.cpu: hardware has 6 breakpoints, 4 watchpoints
Info : Listening on port 3333 for gdb connections
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Then starting GDB:
./arm-none-eabi-gdb ~/eclipse-workspace/test-blink-led/Debug/test-blink-led.elf
then running the following command in gdb:
(gdb) target remote localhost:3333
Remote debugging using localhost:3333
Remote connection closed
As it shows gdb connection drops instantly and OpenOCD prompts the following errors:
Info : accepting 'gdb' connection on tcp/3333
target halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0x080022e6 msp: 0x20017ff8
Info : device id = 0x10076415
Warn : STM32 flash size failed, probe inaccurate - assuming 1024k flash
Info : flash size = 1024kbytes
Error: auto_probe failed
Error: Connect failed. Consider setting up a gdb-attach event for the target to prepare target for GDB connect, or use 'gdb_memory_map disable'.
Error: attempted 'gdb' connection rejected
Error: jtag status contains invalid mode value - communication failure
Polling target stm32l4x.cpu failed, trying to reexamine
Examination failed, GDB will be halted. Polling again in 100ms
So from those geeks who do it on a similar platform on a daily basis, can anyone help and tell me where am I doing wrong. Does missing any compile-time flag might result in this problem?
I'm scratching my head for a couple of days now so please let me have your hints.
One of the reasons may be that your STLINK firmware seems pretty old (STLINK V2J28M17 as your log shows). I suggest downloading the STSW-LINK007 application to upgrade the firmware. The software is a multiplatform Java application. It works flawlessly in Debian GNU/Linux.
Currently, I use another gdb server texane/stlink for my debugging task with GDB without any problem on some Nucleo and also custom boards. I use target extended-remote command to join the port of the server. Maybe you can try to connect with this command also under OpenOCD.