Image Number 11 for United States Patent #8122413.
Logic blocks for IC designs (including gate-array, standard cell, or logic array designs) provide Design-for-Test-enabled flip-flops (DFT-enabled FFs) that inherently insure compliance with DFT rules associated with scan shifting. Test scan-chains are configured by daisy-chaining instances of the logic block in a transparent (invisible) manner to user-designed application circuits, which can be designed without any user-inserted test structures or other regard for DFT considerations. User asynchronous set and reset inputs and all Stuck-At faults on all user pins on these DFT-enabled FFs are observable via capture and scan-out. A first type of these DFT-enabled FFs features addressable control to partition test the application circuit. A second type of these DFT-enabled FFs features integral capture buffering that eliminates the need for partition test, simplifying control logic and reducing the number of test vectors needed.