Patent ID: 7581149

Claim:
A scan-chain extracting method for extracting data regarding scan chains to which a test pattern for testing an integrated circuit is input, executed by programmed processor, the scan chains being constituted by sequence circuit devices, the scan-chain extracting method comprising the steps of: defining control-circuit scan chains constituted by the sequence circuit devices, the sequence circuit devices being disposed in a test control circuit for controlling inputting of the test pattern; setting an initial value for the sequence circuit devices constituting the control-circuit scan chains; setting the scan chains to through states so that input signal values pass through the scan chains without change; extracting data regarding the scan chains; determining whether or not all data regarding all the scan chains have been extracted, all the scan chains being provided in the integrated circuit; changing the initial value for the sequence circuit devices of the control-circuit scan chains included in the test control circuit, when at least one of the data regarding the scan chains have not been extracted, the sequence circuit devices being connected to other sequence circuit devices located at start points of the scan chains; and extracting data regarding the scan chains by tracing the sequence circuit devices included in the integrated circuit.