摘要:
A method and apparatus for selectively masking off unknown (‘x’) captured scan data in first selected scan cells 220 from propagating through the scan chains 221 for test, debug, diagnosis, and yield improvement of a scan-based integrated circuit 207 in a selected scan-test mode 232 or selected self-test mode. The scan-based integrated circuit 207 contains a plurality of scan chains 221, a plurality of pattern generators 208, a plurality of pattern compactors 213, with each scan chain 221 comprising multiple scan cells 220, 222 coupled in series. The method and apparatus further includes an output-mask controller 211 and an output-mask network 212 embedded on the scan data input path of second selected scan cells 222, or a set/reset controller controlling selected set/reset inputs of second selected scan cells. A synthesis method is also proposed for synthesizing the output-mask controller 211 and the set/reset controller.
摘要:
A method and apparatus for selectively masking off unknown (‘x’) captured scan data in first selected scan cells 220 from propagating through the scan chains 221 for test, debug, diagnosis, and yield improvement of a scan-based integrated circuit 207 in a selected scan-test mode 232 or selected self-test mode. The scan-based integrated circuit 207 contains a plurality of scan chains 221, a plurality of pattern generators 208, a plurality of pattern compactors 213, with each scan chain 221 comprising multiple scan cells 220, 222 coupled in series. The method and apparatus further includes an output-mask controller 211 and an output-mask network 212 embedded on the scan data input path of second selected scan cells 222, or a set/reset controller controlling selected set/reset inputs of second selected scan cells. A synthesis method is also proposed for synthesizing the output-mask controller 211 and the set/reset controller.
摘要:
A method for generating stimuli and test responses for testing faults in a scan-based integrated circuit in a selected scan-test mode or a selected self-test mode, the scan-based integrated circuit containing a plurality of scan chains, N clock domains, and C cross-clock domain blocks, each scan chain comprising multiple scan cells coupled in series, each clock domain having one capture clock, each cross-clock domain block comprising a combinational logic network. The method comprises compiling the scan-based integrated circuit into a sequential circuit model; specifying input constraints on the scan-based integrated circuit during a shift and capture operation; specifying a clock grouping to map the N clock domains into G clock domain groups, where N>G>1; transforming the sequential circuit model into an equivalent combinational circuit model according to the input constraints and the clock grouping; and generating the stimuli and test responses on the equivalent combinational circuit model according to the input constraints.
摘要:
A method and apparatus for time-division demultiplexing and decompressing a compressed input stimulus 421, provided at a selected data-rate R1 421, into a decompressed stimulus 424, 426, 433, 435, driven at a selected data-rate R2 442, for driving selected scan chains in a scan-based integrated circuit 401. The scan-based integrated circuit 401 contains a high-speed clock CK1 443, a low-speed clock CK2 442, and a plurality of scan chains 411, . . . , 418, each scan chain comprising multiple scan cells coupled in series. The method and apparatus comprises using a plurality of time-division demultiplexors (TDDMs) 402, 403 and time-division multiplexors (TDMs) 408, 409 for shifting stimuli 421 and test responses 444 in and out of high-speed I/O pads. When applied to the scan-based integrated circuit 401 embedded with one or more pairs of decompressors 404, 405 and compressors 406, 407, it can further reduce the circuit's test time, test cost, and scan pin count. A synthesis method is also proposed for synthesizing the time-division demultiplexors (TDDMs) 402, 403, decompressors 404, 405, compressors 406, 407, and time-division multiplexors (TDMs) 408, 409.
摘要:
A multi-level scan compression method and apparatus for reducing test data volume and test application time in a scan-based integrated circuit without reducing the speed of the scan chain operation in scan-test mode or self-test mode. The scan-based integrated circuit contains one or more scan chains, each scan chain comprising one or more scan cells coupled in series. The method and apparatus comprises two or more decompressors embedded between N compressed scan inputs and M scan chains, where N