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# Prime Faults in a Double Bit Partition Programmable Logic Array

IP.com Disclosure Number: IPCOM000084928D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 67K

IBM

Cha, CW: AUTHOR

## Abstract

In testing logic circuits, stuck fault is one of the most dominant fault behaviors. To meet the quality assurance, a circuit must pass the test set that will detect all stuck faults in the circuit. Programmable Logic Array (PLA) is a special kind of circuit with regular structure. Without exception, it is also vulnerable to stuck fault. To generate a complete test set of a PLA for all the stuck faults, it is possible to employ a program that will use "stuck-at-0" fault criterion for all the input lines of all NOR gates, and both stuck-at-0 and stuck-at-1 faults of all the output lines of all NOR gates to generate the test set.

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Prime Faults in a Double Bit Partition Programmable Logic Array

In testing logic circuits, stuck fault is one of the most dominant fault behaviors. To meet the quality assurance, a circuit must pass the test set that will detect all stuck faults in the circuit. Programmable Logic Array (PLA) is a special kind of circuit with regular structure. Without exception, it is also vulnerable to stuck fault. To generate a complete test set of a PLA for all the stuck faults, it is possible to employ a program that will use "stuck-at-0" fault criterion for all the input lines of all NOR gates, and both stuck-at-0 and stuck-at- 1 faults of all the output lines of all NOR gates to generate the test set.

A set S of stuck faults is called a set of prime faults, if any test set that detects all the prime faults in S will detect all the stuck faults in the whole circuit
C. Obviously, the smaller the set S of prime faults is, the easier the test set generation will be. But, it also must be simple to find the set S for any given DBP PLA.

(Image Omitted)

An example of a two-bit adder DBP PLA is shown in Fig. 3. The set of prime faults are line 1, 2, ---, 18 and line l(11), l(12), ---, l(18) and line l(21), l(22), ---, l(28) stuck-at-0. To generate a test set for all stuck faults of Fig. 3, it is only necessary to consider those 34 prime faults.

It is evident by the method that the number of prime faults are the sum of the number of personalities in the FLA plus 4 x I where I is the...