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I am using ST-LINK/V2. In this module we have 20 pins:

  • Pin 4 RX
  • Pin 6 TX

What is the use of RX and TX Pins? Can I use those pins as serial communication(USART) pins? If it is not possible then what is the use of those pins?

ST-Link connector

glts
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Devilal guguloth
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  • Yes, it should be possible to use it as UART. When you plugin in the ST-Link to your computer, a virtual COM should appear. – Codo Mar 04 '21 at 08:47

1 Answers1

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The image you have posted is the pinout for the original ST-Link and ST-Link/V2-ISOL.

ST-Link/V2-1, V2-A and V2-B, as well all variants of ST-Link/V3 also expose a virtual COM port over USB.

ST-Link V2.1 etc are embedded in various evaluation boards, they are not available stand-alone and do not use a 20-pin connector.

Your stand-alone ST-Link/V2 does not have this functionality.

The reason that they do not enable it is to avoid problems because all the even pins 4-20 on that connector are supposed to be GND. A typical board will hard wire those pin to the ground plane. If you connect UART pins to ground then you get a short that might be hard to find and impossible to modify in-place.

If you have a custom break-out board and an ST-Link/V3SET then you can lay your board out to use this functionality, just be careful not to connect a standard debugger.

Tom V
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