Thanks for the link but i really want to know how???
Let us suppose i have a PCB with a Xilinx chip on it... how am i going to write a code for it to check for the boundary scan?? and what all does this scan??
JTAG is a mechanize which allows o test the chip/PCB for faults. You can imagine JTAG as a state machine which can load data in PCB and get the data out from that PCB.