JTAG Diagnostics for Intel QPI Structural Defects

For circuit board manufacturers, a self-healing bus like Intelยฎ QPI can be self-defeating. Especially when it comes to board quality and diagnosing structural defects. Functional tests will typically not detect QPI faults like shorts and opens because they can be hidden by QPIโ€™s self-repairing capabilities. Often, QPI buses with structural faults will train up well enough to slip through functional testing, only to manifest user problems later like reduced performance, more lane drop-outs, hangs and others.

Unlike traditional functional test and probe-based test methods like in-circuit test (ICT), which causes signal integrity problems on QPI, JTAG / boundary-scan diagnostics applied through the Intel XDP interface or custom JTAG hardware pinpoints structural problems on QPI.

This eBook shows how JTAG / boundary-scan tests improve manufacturing quality by isolating structural faults on QPI.

Highlights:

  • Self-Healing Hurts Structrual Test
  • Boundary-Scan Test for QPI
  • Diagnosing Faults on QPI
  • A Real-Life Case
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