dev_target_not_halted on stm32h735

[Aya Ahmed]

i’m trying to use stm32h735 chip in my custom board , when it comes to flashing or starting new debug session it gives error like 

  when i’m trying to access it through stm32programmer it gives 

it work and connect after many times of trying to turn off power, or remove the st link cable and put it again, when it connected, I erase the full chip to access it, then try to flash it in the ide, it works for 3 times, then repeat the error again, and I tried in cube programmer to change the mode to under reset mode and press reset button and press connected, it failed, I need to know permanent solution not every time it gives me this 

[mƎALLEm]

Hello ​@Aya Ahmed and welcome to the ST community,

The question is what board are you using? a ST board or a custom board?

If it’s a custom board what is the power configuration of your MCU by hardware? SMPS? LDO? other?

I suspect you set a bad power configuration not inline with your hardware.

Please refer to this knowledge base article: How can I recover my STM32H7/STM32H7RS board after facing a power configuration deadlock?