Multiple input signature testing & diagnosis for embedded blocks in

Abstract

An integrated circuit includes a first circuit module for generating a plurality of digital signals and a second circuit module for receiving the digital signals. A multiple input signature module receives the digital signals that are received by the second circuit module. The signature module generates and stores a signature value which is indicative of data values of the digital signals over a plurality of cycles. The signature module operates in response to control circuitry, which is responsive to a test signal, to cause the values indicative of the digital signals to be stored to the multiple input signature module, each time that valid signal values are received by the second circuit module. The multiple input signature module may be used for diagnostics by capturing data at a single, predetermined cycle. The module may be initialized to a predetermined value to ensure the signature value or, the single value captured, accurately reflects the data value of the digital signals. The control circuitry is further responsive to a signature data signal for causing data stored in the multiple input signature module to be provided on at least a first output pin of the integrated circuit. The integrated circuit includes scan circuitry and the signature data signal causes the multiple input signature module to form a portion of the scan circuitry.