RE: XAUI AC coupling
Rich and all,
I agree that it would be nice to avoid AC coupling if we can still ensure
interoperability.
If we remove reference to coupling altogether, we must add a common mode
specification or definite logic levels; we cannot only specify peak-to-peak
swing as we are now doing and expect interoperability. (All chip-to-chip
interconnect spec's I know of specify either DC-referenced logic levels or
common mode and differential mode levels. Is there an exception? We have
avoided this by mandating AC coupling up to this time.)
An alternative is to mandate CAPABILITY for AC coupling. This allows DC
coupling where compatible implementations permit, but ensures that ALL
implemenations will interoperate via AC coupling.
-Dawson Kesling
Intel Corporation, NCD
916 855-5000 ext. 1273