Patent attributes
An integrated circuit (IC) is disclosed that comprises a circuit portion (100) having a plurality of inputs (102) and a plurality of outputs (106), the plurality of inputs being arranged to receive a test pattern in a test mode of the integrated circuit, the test pattern comprising a plurality of test vectors for feeding to the plurality of inputs in successive clock cycles. The IC also comprises a test arrangement for testing the circuit portion (100), comprising a test pattern generator (110) for generating the test pattern, masking logic (150) for masking selected outputs of the plurality of outputs (106) and a signal generator (130) coupled to the masking logic (150) for generating a masking signal triggering the masking of all of said circuit portion outputs during selected cycles of the successive clock cycles, the signal generator (130) being responsive to clock cycle selection data (s1-st). This way, selected clock cycles or individual flip-flops can be masked out without requiring external control signals. The IC may also comprise a mask storage arrangement (115) for storing masks to mask a plurality of scan chains for all cycles within a pattern.
