ScanWorks^® JTAG Interconnect Pin-Level Diagnostics

Multiple Driver, Single Receiver

An open at one of the drivers causes that driver to be unable to influence the value on the net. This defect is detected at the receiver and diagnosed as a stuck-fault associated with the driver. A power or ground short on one of the drivers is detected at the receiver and diagnosed as a net stuck-at fault.

Multiple Driver, Multiple Receiver

An open at any driver is detected at all receivers with diagnosis similar to the multiple drivers/single receiver fault. An open at one of the receivers is diagnosed as a stuck fault at the receiver. A short to power or ground is detected at all receivers and diagnosed as a net stuck-at fault.

TriState Driver

Defects on the driver cell of a three-state driver are detected and diagnosed the same as above. Open-circuit defects on the tristate control cell is detected as driver output floating; whereas shorts on the tristate control cell are diagnosed as driver output floating or driver output stuck-at depending on whether the short is to the cell-enable or cell-highZ value.

Bidirectional Driver and Receivers

Opens and shorts on bidirectional drivers/receivers are treated as supersets of the tristate and single driver/single receiver faults. Opens are located to the bidirectional cell causing the problem, either as a driver or a receiver. Shorts are diagnosed either to the net (bidirectional cell, stuck-on fault) or to the driver cell (bidirectional cell, stuck-Z fault). Leaky bidirectional (and tristate) drivers are diagnosed as long as the effect produces a hard stuck-at fault.

Ture Bridging Faults

Two separate scan-interconnect structures can be shorted together (a bridging fault, usually caused by solder-to-solder flow). If the short behaves logically, diagnosis is to the two nets, covering the wired-AND, wired-OR, and strong driver behavior of the short.

Cluster Faults

A cluster fault is a short circuit between two nets, one of which is a scan net (scan driver to scan receiver) and the other is a non-scan net (non-scan driver to non-scan receiver). Under some conditions, scan testing can detect the short, but diagnosis may be difficult.

User Interface

When authorized, interconnect pin-level diagnostics replace the net-level diagnostics that are provided with the interconnect test generation tool. The diagnostic report is generated as the tests are applied and is immediately available. The report is available in text or HTML format. The report indicates the pin to which the fault has been diagnosed, along with addition information about the net to which it is connected. Each connection is identified as an input, output, bidirectional, or cluster (non-boundary scan) pin, if known. Each pin listed is linked to the design browser, which can be viewed by clicking on the pin name. The physical pin location is indicated on the design layout view with cross hairs.

Fault Type Summary Table:

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