Browse Prior Art Database

Pattern Subsummation

IP.com Disclosure Number: IPCOM000045808D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Butler, RW: AUTHOR [+4]

Abstract

Subsummation referes to the process of combining test patterns to reduce the total pattern count sent to manufacturing.

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Pattern Subsummation

Subsummation referes to the process of combining test patterns to reduce the total pattern count sent to manufacturing.

A dynamic subsummation technique can be used as an integral part of test generation. This has advantages over the post-subsummation of other algoithms.

Test vectors are combined before the sequencing through latches and arrays has been added. As each combinational test vector (treating latches and arrays as inputs) is generated, it is merged into the earliest possible test vector already in the test buffer (the buffer capacity is 255 vectors). Two test vectors can be merged if corresponding inputs are not conflicting (same value or unassigned). Because subsummation is done before sequencing, the subsume algorithm does not need to consider any sequential dependency between patterns as is the case with post-processing. This results in a more efficient (less time) as well as more effective (fewer patterns) process.

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