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Jacek Pieczaba
Jacek Pieczaba
Associate III
October 9, 2018
Question

SWD interface pins set as GPIO output lines.

  • October 9, 2018
  • 3 replies
  • 874 views

Hello,

Please apologize if I am asking for trivial question but I have following problem. I have set in the STM32CubeMX pins which are used for SWD ( I am using th STM32F103CBT6 ) as an output pins. When I compile the software and program the micro looks that is working but I have lost access via debugger to MCU :(. Could you be so kind and help me to understand how to proceed in order to get back SWD capability.

Thank you very much in advance

With Best Regards,

Jacek

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3 replies

AvaTar
AvaTar
Senior III
October 9, 2018

> ... the micro looks that is working but I have lost access via debugger to MCU :(

That's normal - you can't have your cake, and eat it at the same time.

Using the BOOT0/BOOT1 pins, get into the system bootloader and erase the flash. I think the FlashLoaderDemonstrator supports this functionality, usually over a UART line.

If you can use other GPIO pins for your application, better avoid re-using the debug pins ...

Jacek Pieczaba
Jacek PieczabaAuthor
Associate III
October 9, 2018

Thank you very much for quick suggestion. I will test it shortly and let you know.. Really appreciate

Jacek

Jacek Pieczaba
Jacek PieczabaAuthor
Associate III
October 9, 2018

Hello I was trying this but as you describe but no success. What I did I follow the suggestion from my friend and use the ST-Link Utility and change the setting on Target->Settings to mode to Connect under Reset. After that I was able to get access to the MCU and erase wrong SW.

Thanks a lot

Jacek

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