[gta02-core] USB schematics

[Werner Almesberger]

Rene Harder wrote:
> I finished the USB part and commited to svn.

Bugs (just two):

- R4905 should be R4908

- D4901 should connect to D+, not D-

Style:

- nReset should be nRESET

- why have a bump on nUSB_FLT and EN_USBHOST if nUSB_FLT could be
  straight if EN_USBHOST had a larger bump ?

- I think it's better to put component references on the left side
  of the symbol and the component value right of it (if using a
  vertical orientation).

  For horizontal orientation, reference above value.

- regarding component values for things like the surge protectors,
  it might be better to just put a key parameters, e.g., voltage
  and maybe capacitance, than the somewhat cryptic part number.

- the role of TP4904 would be cleared if it was visually attached
  to USB ground.

- shouldn't USB_D+ and USB_D- be bidirectional ?

By the way, nice cleanup !

Thanks,
- Werner