Patent ID: 8533548

Claim:
In an integrated circuit having at least a first and second interconnected functional element on a substrate, the functional elements having data lines providing inputs and outputs, and a plurality of wrapper cells for integrated circuit testing placed in series with data lines of the first and second functional elements, the wrapper cells comprising: a functional input receiving an output from the first functional element; a functional output providing an input to the second functional element; two test data inputs each for receiving test data; two test data outputs each for outputting test data; no more than two data storage elements each holding one binary bit; no more than two multiplexers each switching a common output between two inputs according to corresponding control signals defining multiplexor states; interconnecting conductors between the inputs, outputs, data storage elements, and multiplexers so that the multiplexers may be switched to: (a) connect the functional input to the first data storage element; (b) connect the functional output to the second data storage element; (c) connect a first of the test data inputs to a first of the test data outputs through the first data storage element; and (d) connect a second of the test data inputs to a second of the test data outputs through the second data storage element.