Troubleshooting bricked Discovery STM32H745I board

[Michael98006]

I tried flashing a project created for the STM32H745I-DISCO board in CubeMx. The only change I made was disable a few unused peripherals, enable memory caching. I set the clock speed for the M7 core to 480MHz and the M4 core speed to 240MHz. I added a couple of lines of code to blink the LD1 LED in the CM7 project and blink the LD2 LED in the CM4 project. Programming CM7 from IAR went ok and I was able to observe the LD1 LED blink, but once I programmed the CM4 core, the board stopped being recognized by IAR and the ST-Link utility. The ST-Link still works (the ST-Link utility can see its serial number and a USB mass storage device shows up in the file system when I connect the board to the USB port), but neither IAR nor ST-Link utility can recognize the target device (the MCU). The ST-Link utility says "Detection Failed" under "Target" on the Settings dialog. I checked my ST-Link utility setup by connecting an identical Discovery board to my computer, and it worked well. What can I do to troubleshoot my bricked Discovery board?

[hansd56]

Hi,

Power off board (unplug from USB)

Press reset and hold

Power on board

Click on 'Full chip erase' icon

OK

Release reset button

Full chip erase should start

I have got the same board.

[Michael98006]

This procedure worked! Thank you so much! How do you program your board? It looks like every time I program mine, my board gets bricked and I have to follow the steps above to recover it. To be exact, I created a project in CubeMx with all defaul values selected for my board, and I can't get past CM7 core programming step. As soon as I program CM7, my debugger stops working.

[hansd56]

I use the debugger icon to set up a debugger configuration. You can disable one core from downloading by not selecting the corresponding .elf file.

You are using IAR so I am not sure and it might be different. But when you download your code the start.s file is executed before main is called. Set a break point in start.s at the entry point and step trough it.

[Tesla DeLorean]

If it has power supply setting issues, you can find the BOOT0 pin and strap it high, cycling the power a couple of times.

In this mode you should be able to erase the whole chip, connect under reset options may also stop your code from executing.

Identify what your code is doing, like disabling debug, interfering with SWD pins, or going into low power states, so you can avoid these failures in the future.