When we set out to support gumstix, we knew that we couldn't support every daughterboard that would fit the 92-pin connector, so we picked one, a NIC, and worked from its requirements. This uncovered a lot of requirements and a lot of gaps in the online documentation. Howard and a number of OGML members worked very hard to find out what we needed to know (both electrical and physical specifications), but unfortunately, we were not able to get the information we needed in a timely manner. As such, Howard had to make an intelligent decision and go with it.
The solution we are providing uses a 92-pin gumstix connector, but it is not electrically compatible with 92-pin gumstix devices. All of our daughterboards will have to be custom-designed, although aside from the NIC, this would have been the case anyhow, due to the placement of the connector on OGD1. You can see the details on the schematic (forthcoming), but in the abstract, we provide the following: RGBHV inputs from the lower DVI-I connector, 2.5v power and ground, and 33 differential pairs. Certain applications, like LVDS, require that signals be sent differentially, so we have wired the connector to support this. Those 33 pairs can be configured as 33 pairs or as 66 individual digital signals or perhaps some combination. We decided that it would be too risky to also include video-in on OGD1, and it would take signals away from other applications. So we provide only the connector. We intend to follow up with a daughterboard that has video-in capability on it. This can be self-contained, as the video signals can come into the DVI-I connector and the digital decoding can go straight to the Spartan, all through the gumstix connector. Note that any daughterboard you attach will technically violate PCI spec, as it will stick out from the underside of the board. We don't have much choice in this. You just need to reserve a PCI slot "behind" OGD1 for this purpose. -- Timothy Normand Miller http://www.cse.ohio-state.edu/~millerti Open Graphics Project _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
