Process for identifying defective interconnection net end points in boundary scan testable circuit devices

A process for diagnosing test result data produced during boundary scan testing of a circuit device having a plurality of endpoints interconnected in a plurality of nets, the process comprising:

• entering items of test pattern data into a pattern description data structure, each item of test pattern data identifying a particular endpoint enabled to drive during a corresponding test pattern;
• entering items of net layout data into a net layout data structure, each item of net layout data identifying a net of interconnected endpoints;
• entering items of failure data into a failure description data structure, each item of failure data identifying an endpoint that failed to produce an expected test value during a boundary scan test and a corresponding test pattern used during the failed boundary scan test;
• processing the failure description data structure for each test pattern in the pattern description data structure during which a failure occurred, said test pattern processing including;
• identifying from the pattern description data structure a specific one of the endpoints in the first net as the driving endpoint in the test pattern being processed,
• identifying from the net layout data structure all endpoints interconnected in the first net,
• determining from the failure description data structure if the endpoints interconnected in the first net to the driving endpoint are listed in the failure description data structure as failed during the boundary scan test using the test pattern being processed,
• assigning failure priorities to the endpoints interconnected in the first net for the test pattern being processed based upon predetermined priorities selected according to the symptom pattern of failures of the endpoints in the first net as listed in the failure description data structure,
• repeating the processing until each test pattern has been processed;
• and generating a failure report based upon the assigned priorities.

A process for diagnosing test result data produced during boundary scan testing of a circuit device having a plurality of endpoints interconnected in a plurality of nets, the process comprising:

• entering items of test pattern data into a pattern description data structure, each item of test pattern data identifying a particular endpoint enabled to drive during a corresponding test pattern;
• entering items of net layout data into a net layout data structure, each item of net layout data identifying a net of interconnected endpoints;
• entering items of failure data into a failure description data structure, each item of failure data identifying an endpoint that failed to produce an expected test value during a boundary scan test and a corresponding test pattern used during the failed boundary scan test;
• processing the failure description data structure, the pattern description data structure and the net layout data structure in two passes to identify failed endpoints,
• the first pass comprising test pattern processing for each test pattern generating an item of failure data in the failure description data structure, said test pattern processing including assigning failure priorities to each endpoint for each test pattern processed, said failure priorities being assigned according to the symptom pattern of failures listed in the failure description data structure, and
• the second pass comprising net processing for each net having a failed endpoint in the failure description data structure, said net processing including identifying a list of failed endpoints according to the failure priorities assigned in the first pass.