Abstract: A system for efficient utilization of multiple test systems may include an apparatus for testing an electronic circuit board, which comprises a number of computer readable media containing computer readable program code comprising code for a test analysis system that interfaces with at least two test systems. The test analysis system reads a description of said board's board topology and analyzes a number of potential defects of said board based on that description. The test analysis system creates at least two test procedures for the at least two test systems by creating a first test procedure to test the electronic circuit board on a first test system of the at least two test systems. The system then creates at least one other test procedure to test the electronic circuit board on at least one other test system of the at least two test systems.

Abstract: A digital signal detector for sampling the state of a high speed digital signal occurring at a test node in a digital circuit which exhibits the same behavior with repeated applications of the same inputs. The digital signal detector samples the state of a test circuit node at discrete intervals in time and stores the digital levels with timing reference information. The stored information is then compared to the expected behavior of the tested node for analysis of delay-type and other parametric faults, such as performance faults. The digital signal detector includes a state discriminator which determines the state of the input digital signal by comparing its voltage level to one or more threshold voltages.

Abstract: A method for generating improved detection and diagnostic test patterns and for improving the diagnostic resolution of interconnect testing of a circuit is based on the premise that short-circuits are most likely to result from solder bridges between closely adjacent pins. In a first embodiment, an optimal boundary-scan test pattern is generated. In a second embodiment, boundary-scan test diagnosis is enhanced by utilizing x,y coordinate data corresponding to the physical location of devices on the tested circuit. In a third embodiment, diagnosis of unpowered short-circuit testing is enhanced.

Abstract: A method for testing a circuit board having both boundary-scan and non-boundary-scan devices is provided. The test method distinguishes boundary-scan nodes from non-boundary-scan nodes and uses cartesian coordinates (X,Y) of every pin of every device on the circuit board to determine a number of sets of non-boundary-scan nodes that are within a predetermined distance "R" from a device pin coupled to a boundary-scan node. The number of sets of non-boundary-scan nodes are grouped into "independent" groups which can be tested in parallel. A test cycle is performed by testing independent non-boundary-scan nodes in parallel by forcing drivers in the boundary-scan devices to a first logic state, and forcing each of the non-boundary-scan nodes to another logic state for a brief interval. Receivers on the boundary-scan devices capture a response vector during the brief interval, which is scanned out of the circuit board for evaluation.

Abstract: A method for testing a circuit board having both boundary-scan and non-boundary-scan devices is provided. The test method distinguishes boundary-scan nodes from non-boundary-scan nodes and uses cartesian coordinates (X,Y) of every pin of every device on the circuit board to determine a number of sets of non-boundary-scan nodes that are within a predetermined distance "R" from a device pin coupled to a boundary-scan node. The number of sets of non-boundary-scan nodes are grouped into "independent" groups which can be tested in parallel. A test cycle is performed by testing independent non-boundary-scan nodes in parallel by forcing drivers in the boundary-scan devices to a first logic state, and forcing each of the non-boundary-scan nodes to another logic state for a brief interval. Receivers on the boundary-scan devices capture a response vector during the brief interval, which is scanned out of the circuit board for evaluation.

Abstract: The (X,Y) positions of the nodes in a circuit containing boundary scan components and non-boundary-scan components are stored in a computer. The computer selects a set of non-boundary scan nodes within a radius R of a selected boundary-scan node, R being the length of solder bridges in the circuit. A logic 0 voltage is applied to the set and a boundary-scan test is performed. If the boundary-scan test fails, a fault is declared in the circuit between the set and the selected boundary-scan node. A logic 1 voltage is applied to one of the nodes in the set, and the test repeated. If the test returns different results, the fault is declared between that one node and the selected boundary-scan node. A time limit is established for each non-boundary scan node corresponding to the length of time a short in that node can be tolerated. The boundary-scan nodes in the circuit are tested in the order of ascending time limits in its associated set.

Abstract: An apparatus for diagnosing faults in a device equipped with boundary-scan test capability stores serial test data upon detection of a fault in a device under test (DUT). Test data corresponding to a frame vector associated with the fault is formatted so that all information from parallel tester inputs and TAP scan registers can be simultaneously analyzed. A method for diagnosing faults is also disclosed.

Abstract: The (X,Y) positions of the nodes in a circuit containing boundary scan components and non-boundary scan components are stored in a computer. The computer selects a set of non-boundary scan nodes within a radius R of a selected boundary-scan node, R being the length of solder bridges in the circuit. A logic 0 voltage is applied to the set and a boundary-scan test is performed. If the boundary-scan test fails, a fault is declared in the circuit between the set and the selected boundary-scan node. A logic 1 voltage is applied to one of the nodes in the set, and the test repeated. If the test returns different results, the fault is declared between that one node and the selected boundary-scan node. A time limit is established for each non-boundary scan node corresponding to the length of time a short in that node can be tolerated. The boundary-scan nodes in the circuit are tested in the order of ascending time limits in its associated set.

Abstract: An on-chip pull-up which can be selectively enabled/disabled comprises a pull-up transistor (e.g., an FET) connected between the line to be pulled up/down and a bias voltage (e.g., a positive voltage V.sub.DD or a negative voltage V.sub.SS). The control lead (e.g., gate lead) of the transistor is then made externally accessible. Connecting the control lead to V.sub.DD or V.sub.SS either enables or disables the pull-up depending on the particular transistor.

Abstract: Disclosed is a method for compressing sequences of data-vectors, which sequences are to be used for testing circuit boards with the aid of a circuit board testing machine. The method involves an initial compression of the data-vector sequence followed by a so-called K-T transformation of the remaining data-vectors. The initial compression involves eliminating redundant data-vectors from the initial sequence and retaining only the unique data-vectors together with sequencing information indicating where in the initial sequence each unique-data vector occurred. The K-T transformation involves a bitwise logical exclusive-OR operation (XOR) whereby the remaining data-vector sequence is K-T transformed thereby further compressing the sequence without losing any of the original sequence information.