[Gumstix-users] Wiring up USB

[Matthew L. <cyb...@we...>]

Hello,

I am trying to design a simple expansion board for Overo Air, and am 
having trouble wiring up USB.

I just need to connect to one device permanently (a webcam), and I want 
the Overo to be the host.

I'm assuming I can use both the OTG port and the host port.

Can I just wire the D- and D+ lines directly to USBOTG_DM and USBOTG_DP 
(or USBH_DM and USBH_DP)?

The official expansion boards use a differential inductor (whatever 
that's for), is it really necessary?

What about VBUS? Documentation says USBOTG_VBUS is "power out from the 
PMIC". Does that mean it will output 5V from an onboard boost converter? 
(since the input is only 3.3V). More confusing is the USBH_VBUS, which 
says "power in from expansion board"?! Does that mean I need to generate 
5V myself? In that case, why do I need to feed it to the Overo?

And if it already generates 5V for the OTG port, why not do it for the 
host port too?

Thanks for any help! Sorry if I sound very confused... that's because I 
am :)

Matthew