IJTAG vs JTAG vs IEEE 1500 ECT | Technical Tutorial - Second Edition

Technology changes over time. Along the way, industry standards must change to keep up with technology. It should come as no surprise that since 1990, when the IEEE 1149.1 Boundary-Scan Standard (JTAG) was ratified, new standards have been needed to better deal with technical issues never imagined three decades ago. Issues like: IP portability, easy IP re-use, embedded chip and board validation and test, scalability, environmental monitoring, sustainability and others.

The exponential proliferation of embedded instruments and other types of embedded IP over the last 10 years has driven the development of new standard like the IEEE 1687 embedded instrument standard (Internal JTAG or IJTAG) and IEEE 1500 embedded core test (ECT). Of course, IJTAG and 1500 were never intended to replace JTAG. The capabilities of all the three are complementary. In fact, while IJTAG and 1500 provide new capabilities not found in JTAG, they rely on the infrastructure defined in the JTAG standard.

The second edition of our eBook, “IJTAG vs JTAG vs 1500 ECT,” clearly delineates why all three standards are needed and where each one shines. The second edition has been expanded to better compare and contrast how IJTAG more efficiently meets the requirements of embedded IP than does the revised IEEE 1149.1-2014 JTAG standard.


  • IJTAG’s sustainable scalability
  • Ensuring portable IP
  • IJTAG’s reconfigurable on-chip IP network
  • Distributed (IJTAG) vs centralized (JTAG) instruction processing
  • Why two PDL languages?