Why is M4 reset multiple times when entering debug mode?

[HAPPYDAY]

Is there any reason why M4 is reset multiple times when entering debug mode in STM32CubeIDE? Is this normal?

For example, in the case of an application that toggles GPIO, GPIO defaults to low while entering debug mode, then toggles, then goes low and toggles again. When entering debug mode completely, GPIO stays low and then toggles. (Original operation)

It doesn't matter whether it completely enters debug mode and works, but it seems that m4 is reset several times while entering debug mode. I want to know why and is this normal?

[TDK]

On MCUs at least, it is normal by default. The first reset is for it downloading the program. You can prevent it by changing some options in the debug configuration. Possibly similar options exist on MPUs.

[HAPPYDAY]

Thank you for answer. It has been helpful.

[Olivier GALLIEN]

Hi @HAPPYDAY​ ,

I understand you are working on STM32MP1 product right ?

Can you elaborate further your environment setup ( board, tool and software version) then also specify if you are using engineering boot or production mode (with linux running on A7)

I could then comment further if what you are observing is normal or not.

Olivier

[HAPPYDAY]

HI. Olivier GALLIEN

Related information is below.

IDE: STM32CubeIDE 1.6.1

Board : STM32MP157C-DK2

Image: Distribution Package (openstlinux-5.10-dunfell-mp1-21-03-31)

Firmware Package Version : STM32Cube FW_MP1 V1.4.0

Using production mode (using A7 Linux)