ST-link V2 effects on currents

[turboscrew]

Posted on September 16, 2017 at 15:52

How does ST-link V2 affect current measurements of an MCU?

It seems that while connected, it draws quite a lot of current - compared to a low power device.

And how about if the ST-link is disconnected (the USB-cable) from the PC while still connected to the board?

It looks like it still draws current + keeps the core from running.

#st-link

[Tesla DeLorean]

Posted on September 16, 2017 at 17:16

A stand-alone ST-LINK, or one on a NUCLEO/DISCO?

The stand-alone takes a VTarget voltage to power buffers/level-converters.

Low-power tends to be about what you're connecting too, and what current pins to the external world sink or source.

Create tests where you don't need an external debugger attached to determine power states and consumption.

[turboscrew]

Posted on September 16, 2017 at 19:46

A proprietary board, and ST-link V2 POD.

And I was wondering especially the effects that an ST-link V2 can cause if left connected to the board (uC via ribbon cable) but not to computer (USB-cable disconnected).

[Vangelis Fortounas]

Posted on September 16, 2017 at 20:25

Hi.

>>> It looks like it still draws current + keeps the core from running.

Theese effects you described are due to Reset pin of ST-Link connected to NRST pin of your board.

No STLink power , means that NRST pin kept at LO state.

[turboscrew]

Posted on September 16, 2017 at 23:07

That looks like the explanation to what I observed. Thanks!