Single and Variable-State-Skip LFSRs: Bridging the Gap Between Test Data Compression and Test Set Embedding for IP Cores
Vasileios Tenentes, Xrysovalantis Kavousianos, Emmanouil Kalligeros · IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems · 2010
Even though test set embedding (TSE) methods offer very high compression efficiency, their excessively long test application times prohibit their use for testing systems-on-chip (SoC). To alleviate this problem we present two new types of linear feedback shift registers (LFSRs), the Single-State-Skip and the Variable-State-Skip LFSRs. Both are normal LFSRs with the addition of the State-Skip circuit, which is used instead of the characteristic-polynomial feedback structure for performing successive jumps of constant and variable length in their state sequence. By using Single-State-Skip LFSRs for testing single or multiple identical cores and Variable-State-Skip LFSRs for testing multiple non-identical cores we get the well-known high compression efficiency of TSE with substantially reduced test sequences, thus bridging the gap between test data compression and TSE methods.