Patent ID: 7139950

Claim:
A method of segmenting and reconfiguring scan chains to diagnose defects in the scan chains comprising: partitioning a plurality of serially extending scan chains into a plurality of serially arranged segments, such that each serially extending scan chain comprises a plurality of serially extending segments; positioning a plurality of switches, having control inputs to control switching of the switches, between the plurality of segments of each scan chain; controlling the control inputs of the plurality of switches to connect, each segment of each scan chain except an initial segment to a preceding serial segment in the same scan chain, and each segment of each scan chain except a final segment to a next serial segment in the same scan chain, or each segment of each scan chain except an initial segment to a preceding serial-adjacent segment in an adjacent scan chain, and each segment of each scan chain except a final segment to a next serial-adjacent segment in an adjacent scan chain, wherein, depending upon the control inputs to the switches, an output of each scan segment is directed either to a next serial segment in the same scan chain or to a next serial-adjacent segment in an adjacent scan chain, and a preceding serial segment in an adjacent scan chain and the next serial segment in an adjacent scan chain are in different scan chains.