[OpenOCD-user] Anyone using STM32U5 with OpenOCD?

[Rob M. <Rob...@u-...>]

Is anyone here using STM32U5 (on a NUCLEO-U575ZI-Q board, so via the ST DAP on that board) with OpenOCD (v0.12.0-2) reliably?

We've been using OpenOCD with it for a while, driven through Zephyr's "west" tool, but we have just begun using OpenOCD directly instead and find that, every so often, OpenOCD is unable to connect to the target and stays that way (across power-cycles of the board) until eventually, after repeated tries, it begins working again.  We do nothing particularly obvious to cause the problem, or to fix it for that matter.

OpenOCD command line is:

openocd -f /home/rob/cfg/stm32u5.cfg -c "gdb_port disabled" -c "tcl_port disabled" -c "telnet_port disabled" -c "adapter serial 003E004C3532510F31333430" -c "program /home/rob/stm32u5.elf reset" -c "exit"

...stm32u5.cfg is attached.

In all cases OpenOCD finds the DAP:

Info : STLINK V3J12M3 (API v3) VID:PID 0483:374E
Info : Target voltage: 3.291200

...but is unable to identify the STM32U5 itself, messages like:

Warn : target stm32u5x.cpu examination failed

...or:

Error: [STM32U575ZITxQ.cpu] Could not find MEM-AP to control the core

...or just:

Error: init mode failed (unable to connect to the target)

...are emitted.  We are not using secure images, just boring non-secure stuff.

I've tried asking about this on the ST and Zephyr support forums but no answers there.

Rob