avrusb with external power source

[sowisz]

Hi everyone!
Is this possible to use avr usb when powering board from external source (large graphical display)?
What should be the proper schematic diagram?

Thank you in advance.
regards,
Grzegorz Sowa

[christian]

It is possible to use an external supply. I'd recommend taking all the power from your own supply and leave the USB 5V unused. This violates the spec, I think, because your pull-up delivers current when the host is powered off, but that should not cause any real problems.

[Grendel]

Most self-powered devices seem to request 2mA (smallest value possible) via config descriptor for that reason it seems.