Category: Boundary Scan

To quote Ransom Stephens in the DesignCon Community Blog, “BIST (Built-In System Test), is an acronym that would keep executives at test-and-measurement companies awake at night, if they knew what it meant.” What’s he talking about?
As we’ve covered in some previous blogs, the differential, AC-coupled nature of PCI Express allows this bus to be somewhat self-healing, whereby some structural defects will allow the bus to transparently run, albeit at a degraded performance. Due to this, these short-circuit and open-circuit defects may be completely masked from conventional functional test. But such defects are important to detect, because they will affect the throughput of the port. Boundary scan can be used to detect these defects, subject to the implementation of IEEE 1149.1 and IEEE 1149.6 in the chips.