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Delay Test Generation for Designer Specified Critical Paths

IP.com Disclosure Number: IPCOM000088502D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 36K

Publishing Venue

IBM

Related People

Davis, WT: AUTHOR [+4]

Abstract

This article describes an algorithm and a system to ensure that the designer-specified critical paths are used at least once as transition paths in performing delay testing.

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Delay Test Generation for Designer Specified Critical Paths

This article describes an algorithm and a system to ensure that the designer- specified critical paths are used at least once as transition paths in performing delay testing.

Delay-test generation systems generate delay tests for every block input and/or output in both directions of transition in its longest and shortest delay paths on a given large-scale integration (LSI) chip. The transition paths used in delay testing under this strategy, however, do not necessarily cover what designers consider to be critical paths. In the event that a significant percentage of system critical paths is not delay-tested, a product passing delay testing under the above implemented strategy may fail system requirements in a higher level package.

To overcome this problem, the required user input in the present system includes explicit user specification of unique paths from controllable inputs to observable outputs on the LSI chip. An interactive system is proposed to interface with the user to define input critical paths to be delay-tested. The user will be prompted for additional input information when ambiguity of path specification exists. This interactive portion of the system is the algorithm shown in Fig. 1. The output of the algorithm is a table which contains a complete description of the input critical path. This table is then passed to the algorithm shown in Fig. 2 which will generate a delay test for the path specified.

The algorithm of Fig. 1 establishes the path between blocks which the user has defined to be on the path. The user is required to enter a transition source and target which will be the s...