What sort of header is this?

Using Arduino General Electronics
1

Hi, just wondering what this 4 pin header marked G CLK D/O is?

Though at first it was an ICSP, but is missing some pins

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2

I think it's for a 4 digit, 7-segment LED display - could be wrong, though

TM1637_Display

3

It is probably a serial output of some sort. Ground, clock and data out.

4

What is the label for the fourth pin?

5

pert:
What is the label for the fourth pin?

No markings for the 4th pin, unfortunately.

6

So - is it actually connected to anything?

7

Paul__B:
So - is it actually connected to anything?

No, that would make life easier.

As its a STM32 ARM controller was thinking maybe it would be the 4 pin connectors you get on the Blue Pill - STM32duino?

Meaning the unmarked header would be a 3.3v header?

8

I ould guess that it's the SWDIO/SWCLK for programming the chip.