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Ahmed Kamel
Associate II
July 21, 2019
Question

Controlling GPIO in system memory boot-loader

  • July 21, 2019
  • 4 replies
  • 1416 views

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?

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4 replies

Uwe Bonnes
Chief
July 21, 2019

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

Tesla DeLorean
Guru
July 21, 2019

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

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Ahmed Kamel
Associate II
July 24, 2019

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
Associate II
July 24, 2019

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
Associate III
October 6, 2020

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