Skip to main content
Visitor II
October 2, 2025
Solved

STM32H7 programming w/out STLINK

  • October 2, 2025
  • 3 replies
  • 339 views

Hiya. This is my first time working with custom STM PCBs.

I was planning on flashing/programming my custom STM32H7 board (specifically STM32H7A3RGT6) over STLINK and then just do general purpose programming over the USB-C COM Port. However, the TAG connector pitch was the wrong size so I'll need to find an adaptor to connect that to the STLINK module I have.

I was wondering if there is anything I can do in the meantime to program the board? The SWO/SWDIO/SWDCLK pins are broken out and I have a Nucleo L432KC. Are there any guides or tutorials for me to follow for this kind of thing?

Any help is much appreciated :).

    This topic has been closed for replies.
    Best answer by Andrew Neil

    @f3l1xa88077 wrote:

    I was wondering if there is anything I can do in the meantime to program the board? The SWO/SWDIO/SWDCLK pins are broken out


    If the pins are broken out, just connect to them!

    A TAGConnect is just a passive connector/adaptor - there's nothing active or special in it.

     

    PS:

    It would be worth also connecting NRST - that can get you out of some tricky situations ...

    3 replies

    Technical Moderator
    October 2, 2025

    Hello @f3l1xa88077 and welcome to the ST community,

    The second method (not for live debug) is to use the system bootloader: AN2606 "Introduction to system memory boot mode on STM32 MCUs" / Section: 57 STM32H7A3xx/7B3xx/7B0xx devices and Table 125 that provides the interfaces/hardware available for that purpose.

    Explorer
    October 2, 2025

    A simple DIY custom adapter ?

    You would need to check the user manual of the Nucleo L432KC, to see what jumpers / solder bridges are to change to use the onboard ST-Link for an external board.

    Super User
    October 2, 2025

    @f3l1xa88077 wrote:

    I was wondering if there is anything I can do in the meantime to program the board? The SWO/SWDIO/SWDCLK pins are broken out


    If the pins are broken out, just connect to them!

    A TAGConnect is just a passive connector/adaptor - there's nothing active or special in it.

     

    PS:

    It would be worth also connecting NRST - that can get you out of some tricky situations ...

    Visitor II
    October 3, 2025

    Hiya. I've been able to connect my custom H7 board to my STLINK with some breadboard wires, but I'm having issues with actually connecting to the chip.

    23:25:25 : ST-LINK SN : 0029003F3333511731363730
    23:25:25 : V3J15M7
    23:25:25 : Connected via SWD.
    23:25:25 : Connection mode : Normal.
    23:25:25 : Debug in Low Power mode enabled.
    23:25:25 : Can not connect to the target!
    23:25:26 : Unexpected error

    f3l1xa88077_0-1759505648794.png

     

    I've tried swapping pins around to see if I connected them incorrectly, but I only get "Connected via SWD" with the proper connection.

    NRST is pulled high and I have my 2.2uF caps on VCAP.

    Any ideas?

    Technical Moderator
    October 3, 2025

    Are you using ST-LINK utility? 

    Please use STM32CubeProgrammer tool instead. STLINK utility was deprecated since a while.