Browse Prior Art Database

Improved Cutting Algorithm

IP.com Disclosure Number: IPCOM000036617D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 37K

Publishing Venue

IBM

Related People

Savir, J: AUTHOR

Abstract

The cutting algorithm enables computation of bounds on signal probabilities and detection probabilities of faults in networks designed according to the level-sensitive scan design (LSSD) rules *. These bounds are used to determine the necessary pseudorandom test length needed to test a given product using built-in self test (BIST). One of the problems with the cutting algorithm is that is may compute loose bounds that translate into unnecessarily high test lengths. The object of this disclosure is to improve the cutting algorithm so that the computer bounds become satisfactory.

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Improved Cutting Algorithm

The cutting algorithm enables computation of bounds on signal probabilities and detection probabilities of faults in networks designed according to the level- sensitive scan design (LSSD) rules *. These bounds are used to determine the necessary pseudorandom test length needed to test a given product using built- in self test (BIST). One of the problems with the cutting algorithm is that is may compute loose bounds that translate into unnecessarily high test lengths. The object of this disclosure is to improve the cutting algorithm so that the computer bounds become satisfactory.

The improved cutting algorithm is a careful superposition of the original cutting algorithm and the Parker-McCluskey algorithm
[*].

The tightness of the computer bounds may vary depending on what proportion of the circuit is handled with the cutting algorithm and what proportion is handled with the Parker-McCluskey algorithm.

Thus, the user of the improved cutting algorithm can actually control and trade-off the accuracy of the results with the computational effort needed to achieve them.

The improved cutting algorithm uses the cutting algorithm to achieve low complexity computation and the Parker-McCluskey algorithm to increase the tightness of the bounds. The rules of both the cutting algorithm and the Parker- McCluskey algorithm should be followed.

(Image Omitted)

Consider the circuit of Fig. 1. The Parker-McCluskey algorithm applied to the circuit of Fig. 1...