This option captures all data around the trigger position that has been reached. In this case, half of the data prior to reaching the trigger, and half of the data after reaching the trigger, is captured. For example if your buffer size is set to 50, then 25 rows before the trigger point and 25 rows after the trigger point are returned.

  Not all trace devices capture trace information accurately around the trigger. For example, 60% of the data before the trigger and 40% of the data after the trigger might be returned.