Keil Logo

ULINK SWD adapter

Many STM32 development boards do not have standard JTAG, 10-pin or 20-pin Cortex Debug connectors. For such cases, the ULINKpro kit also includes an adapter for the 6-pin SWD interface which is frequently present on STM32 development boards. The figure below shows the adapter.

ULINK SWD adapter front and back view

Connecting to the target board

To use the ULINK SWD adapter with the target board:

  • Make sure that the ULINKpro is assembled with the 20-pin to 10-pin cable used for debug interface.
  • Attach the 10-pin side of the cable to the Cortex debug connector on the top of the ULINK SWD adapter. Due to the connector form factor, only one correct position is possible.
  • Connect the SWD adapter to the 6-pin SWD port on the target board. Note that the VCC pin of  the SWD adapter shall connect to the pin 1 of the SWD on-board port.
  • The ST-LINK jumpers on the development board must be present (ON).
  • On some development boards, pin 1 of the SWD port is not VCC. In such cases, find a VCC (or VDD) pin on the development board which is connected to the supply voltage of the STM32 microcontroller (3.3V in most cases). Then use a jumper wire to connect it to the standalone VCC pin located next to the Cortex Debug port on the SWD adapter front. ULINKpro needs this voltage to adapt the SWD signals to the target voltage.
  • Now you can use ULINKpro to program and debug an application on the target device. Refer to the Setup ULINKpro and Using ULINKpro chapters for details.


The table below explains the SWD adapter pins in details. The Cortex debug connector is explained in the Cortex Debug (10-pin)

Signal Description
VCC Positive Supply Voltage -- Power supply for JTAG interface drivers.
SWCLK Clock pin
GND Digital ground.
SWDIO Data I/O pin.
NRST Reset input -- Connect this pin to the (active low) reset input of the target CPU.
SWO Optional trace output pin.
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.