Method for reducing stored patterns for IC test by embedding built-in-self-test circuitry for chip logic into a scan test access port

摘要

A test method and apparatus allows simultaneous loading of multiple scan chains via a single common scan-in port (SDI) and a scan clock signal SCAN CLOCK. Data is scanned into one or more scanpaths from a scan data in (SDI) port under the control of a clock signal, either directly or indirectly through a linear feedback shift register (LFSR). Scan-out data output from the scanpaths may be read at the scan data out (SDO) port, either directly or indirectly through a signature register with optional masking functionality.