USB client

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To understand how this is intended to function please refer to the PXA255 Design Reference Manual (link broken - archive.org archive).

On page 4-1 (which is 55 of 162) you will see a schematic for the interface of a USB Client port to the PXA255 USB Device Controller.

1. We use GPIOx == Y0_RTS
2. GPIOn == Y0_CTS (The MAX823/TI6823 is used for a clean edge on the 5V-3.3V transition)