Controlling GPIO in system memory boot-loader

[Ahmed Kamel]

Dear all, can i control GPIOs of STM32F030C8 in system memory bootloader? i.e. i need to force a logic low for a specific pin before and while using the boot-loader?

[Uwe Bonnes]

AN2606 does not mention such a capability. So I guess it is not possible.

[Tesla DeLorean]

Perhaps keep relates topics in a single thread https://community.st.com/s/question/0D50X0000B6RTVCSQ4/dear-all-using-stm32f030c8-embedded-system-memory-bootloader-why-the-microcontroller-immediately-reset-after-jumping-to-the-system-memory-bootloader-then-enters-the-application-again-?t=1563725201781

You have no control, the PC could send writes to configure RCC, GPIO, etc, but a bit involved.

Sounds like you need to be writing your own loader, or use pull-downs on pins left tri-stated at reset or by loader

[Ahmed Kamel]

I need to reset specific pin, so this pin keep its state while executing the boot-loader in system memory. Why the embedded boot-loader reset the pins to their default state? Is there any explanation about the state of GPIOs in the embedded boot-loader in ST deocuments?

[Ahmed Kamel]

Its working as intended now after locking the pin before jumping to execute the boot-loader. This freezes the port pin until the next reset.

[Goof Ball]

Hi @Ahmed Kamel​  Locking does not work for me; bootloader still overrides my lock, even for pins not used by the bootloader (ie pins other than USB, CAN, usart, etc, which bootloader obviously needs to use). Any ideas? what chip are you using? I have STM32F405