Deterministic ATPG test coverage is provided in a logic BIST architecture
while reducing test application time and test data volume, as compared to deterministic
ATPG patterns. The logic BIST architecture can include a PRPG shadow operatively
coupled to a PRPG circuit. The PRPG shadow allows re-seeding of the PRPG circuit
with zero cycle overhead. Two compressions can be provided. In a first compression,
multiple tests for faults are compressed into one pattern. In a second compression,
multiple deterministic ATPG patterns can be compressed into one seed. All patterns
provided from the PRPG can be controlled by these seeds so that all care bits are
properly set, while all other scan cells are set to pseudo-random values from the
PRPG. In this manner, the PRPG can rapidly deliver highly pertinent data to the
scan chains of the device under test.