Probes can be configured as data or trigger or both in the ILA IP Configuration wizard as shown in the following figure.
Figure 1. Configurng Probes as Trigger and Data
Probes that participate in trigger or capture compare values are configured as "trigger" only probes. This optimizes the use of BRAMs by the ILA core. Typically, probes whose data needs to be captured are configured as "data" only probes. Probes that participate in both trigger compare values, and whose data needs to be captured should be configured as "trigger and data".