Connecting to STM32 Nucleo boards
The debug interface signals have to be connected manually with the J-Link (e.g. by using jumper wires).
Pins needed for SWD interface connection:
- SWDIO / TMS
- SWCLK / TCK
- SWO / TDO (optional)
- NRST (optional, see below)
- VTref (Usually connected to Vdd of the target)
NRST: We recommend to connect the this pin as for STM32 devices this pin allows us to connect under reset. So even if a "bad" application, which for example remaps the debug pins, is running on the target we can connect to it.
On the Nucleo boards, a separate connector (CN4) is mounted which can be used to connect the SWD interface.
Nucleo CN4 J-Link Pin 2 (TCK) <--> Pin 9 (SWCLK / TCK) Pin 3 (GND) <--> Pin 4 (GND) Pin 4 (TMS) <--> Pin 7 (SWDIO / TMS) Pin 5 (NRST) <--> Pin 15 (nRST) Pin 6 (SWO) <--> Pin 13 (SWO / TDO) Any Vdd Pin <--> Pin 1 (VTref)