This paper introduces a Built-In Self Test (BIST) structure referred to as Universal BIST (UBIST). The Test Pattern Generator (TPG) of the proposed UBIST is designed to generate an one of the three classes of test patterns - deterministic, pseudo-exhaustive, and pseudo-random - to satisf the specific test requirement of a Circuit Under Test (CUT). Further, while generating the pseudo-random test patterns, the TPG can avoid generation of a given set of patterns declared prohibited for the CUT. The theoretical framework of CA noted in [1] has provided the foundation of this work. Effectiveness of the UBIST structure is validated through extensive experimentation.