User`s guide

If a “don’t care” trigger condition is set, this message indicates:
For an HP 16511B Logic Analyzer, only one of the two cards is receiving
its state clock. Refer to “Slow or Missing Clock.”
For an HP 16510A,B Logic Analyzer, the pattern duration is probably set
to less than (<) instead of greater than (>). Since a “don’t care” pattern is
always true, the “less than” condition is never satisfied. Set the trigger
correctly for the measurement that is desired.
If You Have a Problem
“Waiting for Trigger”
MC68306 Preprocessor A–15