Digital and Mixed Signal Testing Technology the Standards IEEE 1149.1 and IEEE 1149.4
Among all the On-Chip Built-In Self-Test (BIST) technologies, JTAG is the most well-known and widely used. In this paper, the mechanism of basic JTAG (IEEE 1149.1) has been discussed. The pitfalls of the method are also discussed, some of which are rectified in the future standard, IEEE 1149.4 for Mixed Signal testing, which is also described here. Many of the valuable research papers on these standards are analyzed. Starting from mid '70s, the structural testing of the PCB circuits has been done using the traditional in-circuit mechanism which is often known as bed-of-nails technique.