01. ST LINK pinouts

Use this page before connecting anything to the VCU.

Required Signals

For normal SWD access you usually need:

• SWDIO
• SWCLK
• GND
• 3.3 V reference if your adapter needs target voltage sensing

For connect-under-reset modes you also need access to reset:

• genuine ST-LINK: connect the adapter reset pin to the MCU nRST line;
• clone ST-LINK: manually connect C45 to GND when prompted by the launcher.

On these VCUs, capacitor C45 is connected to the MCU reset line.

Important Notes

• Do not rush the wiring.
• Use short, stable wires.
• Keep GND connected.
• Avoid holding probes by hand while flashing if possible.
• If the tool gives cryptic OpenOCD errors, check the physical connection first.

Images

ST-LINK pinout for G3/F3

ST-LINK pinout for new G3

ST-LINK pinout for ZT3

ST-LINK pinout for X3 MCU