BUS SIGNATURE ANALYZER AND BEHAVIORAL FUNCTIONAL TEST METHOD

A bus signature analyzer (BSA) device and method to provide high-speed functional testing of a highly integrated circuit (IC) are provided such that existing automatic test equipment (ATE) can be used. The BSA includes a serially-connected multiple input signature register (MISR), which is coupled to the highly integrated circuit, having a feedback circuit coupled to an output of the MISR to receive an output signal and the feedback circuit being coupled to a plurality of inputs of the MISR to feedback the output signal to the plurality of inputs. The BSA further includes a control circuit coupled to the MISR, such that the control circuit enables the MISR to compress an outgoing data signal, which represents the functional behavior of the IC being tested, into a signature on a valid bus cycle. The method includes disabling the IC to prevent the execution of a diagnostic test program which is loaded into the IC to test the performance of the IC, permitting the IC to execute the diagnostic test program, generating bus cycles, compressing data from the diagnostic test program into a signature in the BSA and outputting the signature to be compared against a known defect-free signature.