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Many STM32 development boards do not have standard 10-pin Cortex Debug Connector. For such cases, the ULINKplus 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:

  • Connect the 10-pin cable to the ULINKplus JTAG/SWD interface.
  • Attach the other side of the cable to the 10-pin Cortex debug connector on the top of the 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 one of the jumper wires to connect it to the standalone VCC pin located next to the Cortex Debug port on the SWD adapter front. The connection is required to supply voltage to the SWD I/O driver as ULINKplus has isolated connection.
  • Now you can use ULINKplus to program and debug an application on the target device. Refer to the Debug chapter for details.


The table below explains the SWD adapter pins in details. The Cortex debug connector is explained in the JTAG/SWD interface

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.
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