Reducing Test Dat Volume Using LFSR Reseeding with Seed Compression
نویسندگان
چکیده
A new lossless test vector compressionn scheme is presentedd whichh combines linear feedback shift register (LFSR) reseedingg andd statistical codingg inn aa powerful way. Test vectors cann be encodedd as LFSR seeds by solvingg aa system of linear equations. The solutionn space of the linear equations cann be quite large. The proposedd methodd takes advantage of this large solutionn space too findd seeds that cann be efficiently encodedd usingg aa statistical code. Twoo architectures for implementingg LFSR reseedingg withh seedd compressionn are described. One configures the scann cells themselves too perform the LFSR functionality while the other uses aa new ideaa of " scann windows " toallowtheuse of a smallseparateLFSR whose size is independent of the number of scann cells. The proposedd scheme cann be usedd either for applyingg aa fully deterministic test set or for mixed-mode built-inn self-test (BIST), andd it cann be usedd inn conjunctionn withh other variations of LFSR reseedingg that have beenn previously proposedd too further improve the encodingg efficiency.
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