Flexible imbedded test system for vlsi circuits

Abstract From the Canadian patent

A logic chip contains a plurality of ranks of flip-flops with combinational logic elements connected in between the flip-flop ranks. Each flip-flop has at least two distinct data paths. The first path is for the normal passage of data to combinational logic units following the rank of flip-flops and, the second path is a test path which is connected directly with the next rank of flip-flops. Operands may be shifted in parallel to bypass combinational logic units and may be directed to selected combinational logic for test purposes. The flip-flops in a rank may be serially scanned or operate in parallel to send specific operands through selected combinational logic units.