Should i order a new USB isolator and try to replace it?
That probably wouldn't help. I did some further "research" - i have an external USB isolator module, which happens to use the exact same Adum3160.
And guess what, this thing behaves exactly the same like the EEZ-PSU, with PSU's Due and also with another standalone Due board.
It also turned out that "software" doesn't matter - the same Win10 system which does not work with Adum+Due-native does also not work with a current Linux on the same hardware.
What is however interesting - while the "Due Prog port" through Adum is detected as "USB Fullspeed" (= USB 1.1), the native port is "USB Highspeed" (= USB 2.0). This at least could explain why the Adum behaves differently for prog and native port...
I also found some sort of solution - i dug out a very old laptop which i kept for, well, things like that
, and this laptop
is able to properly work with Due's native port
with the Adum in between.
Knowing this, i then attached the Due-native to an USB-2 port sitting directly on the mainboard of my Win10 system - and this setup worked!
So the outcome probably is - the Adum simply seems to be a bit picky regarding the USB standard. Avoiding USB ports broken out with headers or hubs seem to help at least sometimes.
My regular laptop however - the system which i use in the lab - still does not work, and "swapping" USB ports is obviously not possible there.
But i think i will now leave the PSU at native port, doing SCPI-tests and fw updates with the old laptop (XP, uh..
) mentioned above...