Boundary-Scan Advantages/Disadvantages

• Advantages

  • Area and speed overhead are lower than scan design
  • Boundary-Scan can be used to do functional testing/debugging
    • IC internal functional tests
    • IC cluster functional tests
    • IC/cluster emulation
      • Control internal buses and nets
    • Hardware/Software integration tests
      • Use internal scan to load/examine registers, single step, load microcode, etc.

• Disadvantage

  • Boundary-scan has some area, speed, and testing overhead in the same manner as scan design

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Boundary-scan has a lower overhead than scan design because, in terms of speed, the increase in normal on/off chip time is much less a percentage increase than is true for scan design. Also, in terms of area, the additional logic is small compared to an I/O pad.

Another major advantage to using boundary scan is that it can also be used to scan in/out functional vectors and responses. This can be useful in a number of design verification tasks.

Boundary-scan does have non-zero area, speed, and testing overheads, and that needs to be considered when adding it.