bigbop

I found a trace from each of the USBH-N (D23) and USBH-P (E22) lines to 15K ohm pulldown resistors just above the CPU, under the shield frame.

At this time, anyone can carry on the search to see if the traces are actually connected outside of the CPU shield. Refer to the photo below with the test points.

There are two pulldown resistors. One is completely under the top corner of the shield. There is a testpad for the USBH-N line so I'm guessing there is probably one for the USBH-P line - maybe on the backside of the PCB.

I still need to find two more lines though - the USBPEN (D22) enable line and the USBHPWR (C23) power supply enable. This is not as simple as the HOST pins as these two GPIO pins can be defined for other purposes. Specifically, the GPIO pin D22 can also be used for AC97_SYSCLK which I think is sound related.

If you plan on soldering a couple of wires to the resistors to make it easier to trace the circuits, make sure to secure the wires to the board using a drop of 5 minute epoxy or some other method. This needs to be done to prevent you from ripping the parts off of the PCB if you pull on the wires. The traces on these boards are only a mil thick and a few mil wide and tear REALLY easily. (One of those "been there - done that" experiences).

Stay tuned :approve:

ps: the references D22, C23, etc refer to the rows and columns of pins on the CPU chip. Refer to the PDF file in Afarre's 1st post for more info.