A novel structure of dynamic configurable scan chain bypassing unconcerned segments on the fly

Most of the implementations of boundary scan chains are of fixed length, typically hundreds or thousands. Because the whole chain is scanned every time, many clock cycles are wasted when only a small part of it is concerned. In this paper, a novel structure of configurable boundary scan chain is proposed. Its length and content can be reconfigured without interrupting the chip's functionality. Experimental result shows that the maximum frequency can be as high as 510.4MHz for a full-configurable chain with 512 cells, under 32 nm process, which is 15.7x better than the intuitive method. The proposed structure has been applied to a processor prototype design, and is expected to meet requirements of different applications.