>
> We've tried various RC terminations at the far end of the trace without
> much luck. So far our best luck has been to slow down the edge by adding a
> capacitor after the series R at the source. We can still see the
> reflection, but the clock edge has not risen very far by that time, so
> we're not to the transition zone of the clock input on the flash. We'll
> continue to experiment with it, including the far end termination.
>
> Thanks for the comments thus far!
>
> Harold

A series resistance at the source will only help by a) slowing the
clock edges, which is good for EMC, and b) somewhat damping the second
round of reflections.
Anyway, I don't know why you would need a capacitor at the end, either
- like I said, you calculate the characteristic impedance of your
trace based on your PCB properties, copper weight, trace width, etc.,
and then you put a resistor of that value at the end of your track.
Of course if your track winds around like crazy and you have lots of
layers with various other things underneath your signal, your
impedance will be changing all the time, and you'll get reflections
out the wazoo everywhere.
Maybe I'm not understanding what is actually happening, or what you've
tried before, but this certainly seems like the way to go.
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