Keep breaking nrf5340-DK boards

[JonasForssell]

Dear forum,

We are using the nrf5340-DK development boards as an intermediate link to flash our own boards containing the nrf5340 chip. This is possible since there is an integrated segger debugger on the boards.

However there is something sensitive in the boards which makes us keeping breaking them. This does not happen when we are using a dedicated segger dongle.

In the most recent issue we were using a new computer which were breaking every board we tried. A previous computer broke them occationally.

This makes us believe that there is something sensitive on the boards. Perhaps related to USB voltage or something else.

Do you recognize this issue? If you could point us to the right point we might be able to repair our broken boards.

Thanks

/Jonas

[Turbo J]

Check PE. Floating ground would put the USB level floating at half mains. Not enough current to cause harm to humans, but electronics may be more sensitive.

You may also want to invest into ESD prevention equipment (wristband/strap etc).

[JonasForssell]

Thanks!

[PaKa]

and make sure to not hot swap the external target, power should be turned of on the nRF5 series DK when you plug in the external board and power the nRF5 DK up before powering up the external. Reverse for turning it of.

[JonasForssell]

I have not done this. Thanks for the tip