On the STM32 Nucleo-F103RB board, there are two connectors on the upper part named CN11 and CN12 respectively. Next to them there's a text that says GND, but if they are grounded why do they have jumpers on them? I couldn't find any relevant info on the manual, other than the fact that these jumpers can be removed to be used in other cases.

  • \$\begingroup\$ They may just be handy storage locations for the jumpers, so they aren't lost if not needed elsewhere. \$\endgroup\$ Mar 26, 2021 at 18:11
  • \$\begingroup\$ @PeterBennett so I can use them normally as grounds, and I can also store the jumpers there when I don't need them? \$\endgroup\$
    – Nefeli
    Mar 26, 2021 at 18:26
  • \$\begingroup\$ What did ST say when you asked? \$\endgroup\$
    – old_timer
    Mar 26, 2021 at 20:44

1 Answer 1


A quote from product manual:

Two unused jumpers are available on CN11 and CN12 (bottom side of the board).

In the board schematics, all four pins are connected to GND.

In short, they are four ground pins, and you can store two jumpers on them.

On boards that have more of them, one on each corner, they also function as stand-offs.


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