The PL to PS Cross Trigger inputs are trigger inputs from PL. You can enable these ports to get the trigger events from hardware and feed to ILA for analyzing/debugging hardware state.
The PS to PL Cross Trigger outputs can be used to set the debug break points in software to halt the hardware. Once the trigger event is given to the hardware, the software accesses the hardware state for debug.
Figure 1. PS-PL Cross Trigger Configuration
