| Title |
A Study on Repair of Scan Design Rule Violations at Clock and Reset Pins of Scan Cells |
| Authors |
김인수(Kim, In-Soo) ; 민형복(Min, Hyoung-Bok) |
| Keywords |
scan design ; rule violations ; gated clock ; gated reset ; fault coverage |
| Abstract |
Scan design is a structured design-for-testability technique in which flip-flops are re-designed so that the flip-flops are chained in shift registers. The scan design cannot be used in a design with scan design rule violations without modifying the design. The most important scan design rule is concerning clock and reset signals to pins of the flip-flops or scan cells. Clock and Reset pins of every scan cell must be controllable from top-level ports. We propose a new technique to re-design gated clocks and resets which violate the scan design rule concerning the clock and reset pins. This technique substitutes synchronous sequential circuits for gated clock and reset designs, which removes the clock and reset rule violations and improves fault coverage of the design. The fault coverage is improved from 90.48 % to 100.00 %, from 92.31 % to 100.00 %, from 95.45 % to 100.00 %, from 97.50 % to 100.00 % in a design with gated clocks and resets. |