Controller supply when flashing via UART

[ANovi.7]

Hello everybody,

I use the STM32H743 and try to flash it via UART, which usually works quite well.

I would like to know whether it is important to de-energize the controller before connecting the programming adapter or the adapter must be connected under voltage?

Here is the error that I encountered after some time:

when trying to start the bootloader, the reset pin was permanently set to low, so that the controller is in a permanent reset. The controller does not run the last flashed program, nor can I start communication with the bootloader.

I thank you in advance for the help!

[Tesla DeLorean]

Check the voltages on the supply and VCAP pins in this condition.

Especially VDDA

C​heck any BOM or PDR options or pin configurations.