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What is jumper between D2 and GND used for?

JBlac
Associate III

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.

1 ACCEPTED SOLUTION

Accepted Solutions
JBlac
Associate III

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.

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4 REPLIES 4
JBlac
Associate III

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
Principal

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
ST Employee

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

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

JBlac
Associate III

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.