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NUCLEO-H755 Problem Starting (Failed to execute MI Command/Failed to start GDB server)

paatx
Associate II

I have managed to create a template application on a NUCLEO-H755 that has several CM7 FreeRTOS tasks running to flash various LED patterns combined with a CM4 application that flashes one of the other LEDs.  I have mainly been testing using a run configuration (with LEDs to verify behavior), but sometimes a debug configuration, and when working, the program behaves well and runs overnight.  Flashing and starting the code has always been somewhat questionable (likely due to my inexperience with STM32CodeIDE (V 1.19)), but recently I am no longer able to successfully Run or Debug at all.

The current behavior is as follows:

1) The first time I try to Debug (or Run), I get a "Failed to execute MI Command" with the error indicating failure to finish loading the flash for the CM7.elf.

2) The second time I try the same Debug or Run command, I get a "Failed to Start the GDB server", and I am not able to communicate with the ST-Link on the NUCLEO at all.

3) The only way that I have been able to partially recover is to use STM32CubeProgrammer to clear all device memory after rebooting with the BOOT0 pin pulled high.  After reset, this allows me to inspect the target using CubeProgrammer, but any attempt to Debug or Run from CubeIDE gets me back to step 1.

I am using CubeIDE on a Mac (Sequoia 15.1.1) with the ST-Link/NUCLEO connected through a powered USB hub.  I've check for USB and firewall issues based on extensive reports that I've found online, but everything appears to be fine.

 

Anyone have a similar issue, or any idea what is going on?

 

1 ACCEPTED SOLUTION

Accepted Solutions
TDK
Super User

Check your power settings. PWR_DIRECT_SMPS_SUPPLY is the default.

How to unbrick an STM32H7 after setting the wrong ... - STMicroelectronics Community

If you feel a post has answered your question, please click "Accept as Solution".

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2 REPLIES 2
TDK
Super User

Check your power settings. PWR_DIRECT_SMPS_SUPPLY is the default.

How to unbrick an STM32H7 after setting the wrong ... - STMicroelectronics Community

If you feel a post has answered your question, please click "Accept as Solution".
paatx
Associate II

Well, that definitely worked.  Somehow the supply source setting under RCC in my .ioc was set to PWR_EXTERNAL_SOURCE_SUPPLY, even though I don't think I ever changed it between the working and non-working states.  After changing this to PWR_DIRECT_SMPS_SUPPLY and unbricking the board (full memory erase), everything seems to work now.

I still don't know how it was once working, and then all of a sudden stopped working.

Thanks a million for the help!