Last resort to connect to an STM32 when JTAG deactivate.....

Hello,

as a first time user of STm32CubeIDE, I wanted to toggle a few IOs with a serial output.

I used the JTAG port to connect to the STM32 and program it BUT after the first programing, I can't connect to it anymore.....

Here is the pinout that I used:

Afterwards, I discovered that I should have activated the JTAG debug.... but it is too late.....

What can I do to access/program the STM32 again?

This might be a simple question but I would appreciate the help.

Thank you

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Best answer by Ced77fr

Hello,

After some tests and errors, I was able to get the chip back under JTAG control by:

- putting BOOT0 to 3.3V at startup

- using UART1 (through a USB-TTL serial adapter): PA10 (RX1) and PA9 (TX1) to access the chip and reprogram it.

Now, I have the JTAG programing back.

Thanks for the feedback

Super User

Hi,

depends on..what st-link you use/have ?

usually, just connect "under reset" /hardware , then dont forget to set debug -> SWD .

And avoid using the pins needed for debug to abuse for anything else. :)

Ced77frAuthorAnswer

Visitor II

Hello,

After some tests and errors, I was able to get the chip back under JTAG control by:

- putting BOOT0 to 3.3V at startup

- using UART1 (through a USB-TTL serial adapter): PA10 (RX1) and PA9 (TX1) to access the chip and reprogram it.

Now, I have the JTAG programing back.

Thanks for the feedback

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