$LFSR$ -Based Generation of Partially-Functional Broadside Tests

This paper describes a procedure that computes seeds for
$LFSR$
-based generation of partially-functional broadside tests. Existing
$LFSR$
-based test data compression methods compute seeds based on incompletely-specified test cubes. Functional broadside tests are fully-specified, and they have fully-specified scan-in states. This is the main challenge that the test generation procedure described in this paper needs to address. It addresses it by using a process that modifies an initial seed
$s_i$
in order to reduce the Hamming distance between the scan-in state
$p_i$
that
$s_i$
creates and a reachable state
$r_j$
. When the Hamming distance is reduced to zero, the seed can be used for generating functional broadside tests. When the distance is larger than zero, the tests are partially-functional. Experimental results are presented for transition faults in benchmark circuits to demonstrate the resulting distances and fault coverage.