Board is cleaned up and back on the bench.
Tried out the CDR trigger input for the first time and I'm getting flatlined output. Not sure what happened there.
But it's a pretty low priority for debug because I have so many other things to do and I already have a differential CDR trigger capability in hardware (no firmware to implement it, but it's there when I have time). The single ended was really just a bonus.
I'm not having good luck with comparators on this project though...