What is jumper between D2 and GND used for?

[JBlac]

I see reference to the jumper between D2 and GND, but I don't see any explanation regarding it's use and when it should be on or when it should be off. I'd like an explanation of this jumper please.

[JBlac]

I'm sorry, I have a NUCLEO_L432KC board with the jumper between pins D2 and GND that I'm inquiring about.

Thanks.

[Bob S]

My GUESS is that the pre-loaded the demo firmware looks at this pin to decide what to do. Or else this is an unused pin in the demo firmware and ST wanted to ship an spare jumper clip with the board and that was the safest place to put it :) You ought to be able to get the source for the pre-loaded demo code from (I don't remember where) and find out, if you care.

[Amel NASRI]

Hi @JB.5lacker​ ,

Referring to UM1956, in the section "5.1 Getting started", we have the following:

• Remove the jumper placed between D2 (CN3 pin 5) and GND (CN3 pin 4).
• Observe how the blinking frequency of the green LED LD3 changes, when the jumper is in place or when it is removed.

-Amel

[JBlac]

OK, I get it...as mentioned above, it's something that was shipped with the board and essentially is just changing the frequiency of the green led blink...

Closing this post.