| 摘要 |
PURPOSE:To shorten the test time of an LSI by providing scan chain switching means among adjacent scan chains. CONSTITUTION:The scan chain switching means 37-40 are provided among respective adjacent scan chains 24-27. Then when the LSI23 is tested, the switching means 37-40 are so switched as to form another scan chain encircling a combinational circuit to be tested among combinational circuits 28-36 constituting the LSI23, a test signal sequence is inputted from the corresponding terminal among scan-in terminals 41-44, and a signal sequence outputted from the corresponding scan-out terminal among scan-out terminals 45-48 is observed. Consequently, one scan chain encircling each of all circuits 28-36 can be formed and the circuits 28-36 can be tested by scanning in and out one scan chain corresponding to them. Thus the test time of the LSI23 can be shortened. |
