Abstract: An apparatus for the automatic, in-circuit testing of the electrical properties of complex digital integrated circuit assemblies is disclosed. A programmed processor is provided to control a set of selectable switches, which connect selected nodes of a circuit under test to certain ones of a plurality of signal lines. One of the signal lines supplies a selected digital test signal from a set of selectable test signals to the selected node. The set of test signals including a Gray code. Another of the signal lines provides a response line connecting a selected node to a functional tester that performs one of a selectable number of intermediate functional tests. One of the functional tests is a signature analysis of the digital response signal in accordance with a cyclic redundancy check (CRC) coding technique.

Abstract: An apparatus for the automatic, in-circuit testing of the electrical properties of complex digital integrated circuit assemblies is disclosed. A programmed processor is provided to control a set of selectable switches, which connect selected nodes of a circuit under test to certain ones of a plurality of signal lines. One of the signal lines supplies a selected digital test signal from a set of selectable test signals to the selected node. The set of test signals including a Gray code. Another of the signal lines provides a response line connecting a selected node to a functional tester that performs one of a selectable number of intermediate functional tests. One of the functional tests is a signature analysis of the digital response signal in accordance with a cyclic redundancy check (CRC) coding technique.