EP0489511A2
Expired / Lapsed
EP
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Method and apparatus for diagnosing failures during boundary-scan tests
Assignee: HP Inc
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Filing: 1991-11-14
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Granted: —
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Expires: 2011-11-14
Abstract
Abstract An apparatus for diagnosing faults in a device (16, see Fig. 3) equipped with boundary-scan test capability includes means (including microprocessor 22, state capture RAM 26, 28, vector formatters 30A-30F, and driver/receiver hybrids 32A-32F, 34A-34F) whereby a boundary-scan tester can store serial test data upon detection of a fault in a device under test (DUT). The test data corresponding to the frame vector associated with the fault is formatted so that all information from the parallel tester inputs and the TAP scan registers can be simultaneously analyzed. A method for diagnosing faults is also disclosed.
Inventors
- 👤 Kenneth E. Posse
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:53
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/317; G01R31/3181; G01R31/3185; G01R31/318533; G01R31/318566; G01R31/318555
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
198 words
A boundary-scan tester for diagnosing a fault in a device under test (DUT) (16) having boundary-scan cells (10A-10F) coupled to respective input/output terminals thereof, the boundary-scan tester characterized by: (a) driver/receiver means (32A-32F, 34A-34F) for driving input terminals of the DUT (16) with a parallel input vector and receiving a corresponding parallel output vector from output terminals of the DUT; (b) comparing means (30A-30F, 31A-31F), coupled to said driver/receiver means (32A-32F, 34A-34F), for comparing said output vector with an expected output vector and providing a failure signal indicative of the result thereof and defining a fault; (c) control means (22), coupled to said driver/receiver means (32A-32F, 34A-34F) and said comparing means (30A-30F, 31A-31F), for receiving said failure signal and in response thereto transmitting control signals to the DUT (16) via said driver/receiver means, said control signals causing data captured by boundary-scan cells (10A-10F) associated with the respective input and output terminals of the DUT to be serially shifted out to said driver/receiver means; and (d) storage means (26, 28), coupled to said driver/receiver means (32A-32F, 34A-34F), for storing said input and output vectors and said serial boundary-scan cell data, the stored data being analyzable to isolate the fault.
Claim 2
Dependent Claim
71 words
The boundary-scan tester recited in claim 1, further characterized in that said control means (22) comprises computing means for driving input terminals of the DUT (16) with a series of parallel input vectors and, upon the detection of a fault as indicated by said failure signal, computing a vector number identifying the particular input and output vectors present on the terminals of the DUT at the time the fault was detected.
Claim 3
Dependent Claim
37 words
The boundary-scan tester recited in claim 2, wherein said control means (22) further comprises means for repeating a boundary-scan test up to the last vector in the vector frame present at the time the fault was detected.
Claim 4
Dependent Claim
30 words
The boundary-scan tester recited in claim 1, further characterized by: (e) second control means (22), coupled to said comparing means, for providing said comparing means with said expected output vector.
Claim 5
Dependent Claim
39 words
The boundary-scan tester recited in claim 1, 2, 3 or 4, characterized in that: said driver/receiver means (32A-32F, 34A-34F) comprises a Hewlett Packard part number HP 1SG80076 format chip and a Hewlett Packard part number HP 03066-66561 driver/receiver hybrid.
Claim 6
Independent Claim
134 words
A method for diagnosing a fault in a device under test (DUT) (16) having boundary-scan cells (10A-10F) coupled to respective input/output terminals thereof, characterized by the steps of: (a) driving input terminals of the DUT with an input vector (40) and receiving an output vector from output terminals of the DUT (42); (b) comparing said output vector with an expected output vector (44) and determining whether a fault exists in the DUT (46), and, if a fault is determined to exist, then storing said input and output vectors (48) and performing the following steps; (c) repeating the test up to the end of the vector frame by which the fault was detected and storing portions of the output data from that frame (52); and (d) analyzing the stored data to isolate the fault (54).
Claim 7
Dependent Claim
47 words
The method recited in claim 6, further characterized by the step of storing a vector number upon detection of a fault (50), the vector number identifying the last vector in the vector frame present on the terminals of the DUT at the time the fault was detected.
Claim 8
Dependent Claim
40 words
The method recited in claim 6, further characterized by the step of repeating the boundary-scan test, upon the detection of a fault, up to the last vector in a vector frame present at the time the fault was detected (52).
Claim 9
Dependent Claim
22 words
The method recited in claim 6, further characterized by the step of determining the expected output vector prior to performing step (b).
Claim 10
Dependent Claim
54 words
The method recited in claim 6 or 7, further characterized by the steps of: repeating the boundary-scan test, upon the detection of a fault, up to the last vector in a vector frame present at the time the fault was detected (52); and and determining the expected output vector prior to performing step (b).
References Cited (Backward Citations)
No citation records indexed.
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