What is Boundary Scan?
Boundary scan is a board level design method that provides test access to the input and output pads of ICs on PCBs. Boundary scan changes the IO circuitry of individual ICs, so that the input and output pads of every boundary scan IC can be linked to form one or more serial boundary scan chains.
Boundary scan is used to check for shorts and opens in the interconnect among ICs on PCBs. It performs the checks by using the boundary scan chains to pass logic values b/w the pads of dissimilar ICs.