The various Zorro2/CP controllers use very simple embedded USB controllers with nothing more then byte wide PIO and a interrupt line.

Now i think of it, the easiest to implement might be the Thylacine, it uses a very simple Phillips 8 bit USB chip in sram mode and the whole card is documented.

My goal is not easiest possible for me but most useful choice, for everyone, not just for me. Only single choice allowed!

'Useful' mwuahaha, okay i'll be quiet now :-D

I think you missed the point. Everyone always does it when it is about emulation anyway.

Nah sorry, just my sense of humour failed me.

Some good news. I now have Deneb memory map, register information and used USB chip datasheet. (Thanks to M.Boehmer)

Next step is to find out which VM/emulator/something that does something weird with USB has most usable and license compatible low level USB routines that can be used in UAE.

Something simple at first, like USB mouse or gamepad USB data emulation.

Hi Toni, (Hi Michael B. :) )
I've done a similar thing to use libusb (and libusbX) with WinUAE
http://aminet.net/package/driver/other/anaiis_hostusb
These libraries are complex to install in recent (and descent) Windows but
at he moment, only keyboard/mouse/gamepad (even with effective rumble !) are functioning this way.
I never succeed to adapt my ANAIIS stack to Deneb (cause I don't have the hardware, and no time for that...) but your new project interests me a lot :spin

libusb seems easiest starting point (no need to manually generate fake USB data), "only" need to hook it up with Deneb USB chip. Which is still easier said than done.