Title

TL;DR

  • STLINK-V3MINIE to 2.54mm pin header adapter
  • Target power supply with 5V and 3.3V
  • 3.3V supply is adjustable via resistor divider
  • Current limiting with LED indicator
  • 3D printed case
  • Open hardware: all files available

Introduction

I really enjoy working with STM32 MCUs and ST’s ecosystem, including their debugging adapters. Most of the time, I use the STLINK-V3SET. However, what I don’t like about it is the STDC14 connector with its 1.27mm pitch ribbon cables. Over the last few years, I’ve had several issues related to these cables. A broken wire, or even worse, an intermittent contact, caused delays during development. The problem often appeared as a faulty toolchain and was not easy to detect. I have experienced this issue with other debuggers like the Atmel ICE or the PLS UDE, etc.

For my hobby projects, I therefore use a different kind of connection. Most of the time, I have enough space to fit a standard 2.54mm pin header (single row), which is also used on most of ST’s development boards. So far, I have not experienced any major problems with signal integrity. However, when using this approach, I encountered some disadvantages when using the STLINK-V3SET with its 2.54mm adapter board:

  • When using DuPont cables, the STLINK-V3SET gets messy.
  • The adapter board with the pin headers has a large unprotected area (ESD and short circuit risks).
  • Micro USB connection.
  • Unnecessarily large device (when used with the adapter board).
  • No target power supply options.

My requirements

Therefore I wanted:

  • Smaller footprint
  • USB-C connection
  • 2.54mm pitch connector only
  • Target supply option with 5V and 3.3V (up to max. USB current –> 500mA)
  • Same compatibility with the ST ecosystem

ST released the STLINK-V3MINIE debugger as a cheaper alternative to the STLINK-V3SET. It is the first one with a USB-C connector and provides both a STDC14 and a board-edge connector, while being fully compatible with the ST ecosystem.

Around the STLINK-V3MINIE, I designed a small board that connects to the board-edge connector. It offers direct access to the SWD port as well as the internal VCP port, and provides 5V and 3.3V on a 2.54mm pitch pin header. The pin header is separated into three groups (SWD, VCP, and power supply) but can be used with a 2x10 connector to build custom adapters for different projects.

Required materials

  • PCB (Gerbers are included with the project files)
  • BOM according to the IBOM
  • 2.54mm double-row pin header (2x10)
  • AVX board-edge connector (009159010061911)
  • 3D printed case
  • STLINK-V3MINIE

Assembly

The board is a standard 1.6mm 2-layer PCB. For easy assembly, you should use the “interactive BOM.”

Besides the board assembly, there is one other thing to be soldered. You need to add a jumper cable to the STLINK-V3MINIE in order to route the VBUS (+5V) to the adapter board. The following pictures show how I did it, but you might want to do it differently.

For the case, there are four STL files included in the project files. The bottom part of the case can be printed with or without a cutout for the STDC14 connector of the STLINK-V3MINIE. If you don’t use the connector, you might want to desolder it and use the file without the cutout (mine_adapter_btm_no_con.stl). Otherwise, you should use the default one (mine_adapter_btm.stl). The top part also has two variants. One version has holes for the LEDs to shine through (mine_adapter_top_led_holes.stl). This version should be used if you are using a material that doesn’t allow light to pass through. If you are using a transparent or light material, the other version with minimal material where the LEDs sit is better, as it allows the light to shine through the plastic (mine_adapter_top.stl). You can print with a default layer height of 0.2mm and a standard 0.4mm nozzle. I recommend PETG or PLA+ for some flexibility. Pure PLA might not be the best choice. After printing, you may need to clean up the area around the USB-C connector.

Once you have everything together, just connect the adapter board to the STLINK-V3MINIE using the AVX board-edge connector and place it into the top part of the case. The bottom part is held together with clips, so there is no need for screws. Be careful if you didn’t desolder the STDC14 connector in order to avoid breaking the small plastic pieces on the sides.

Files

STLINK-V3MINIE Adapter REV 1.0 DOWNLOAD

Contact

If you have any questions you can send a mail to info ‘at’ embedded-ideas.de or contact me via mastodon @DerTobi@mastodon.social