Boundary Scan Intelligent Diagnostics (BSID) Overview
The Boundary-Scan Intelligent Diagnostics (BSID) module generates diagnostics for two kinds of boundary-scan tests: Virtual Interconnect Test (VIT), and Virtual Component and Cluster Test (VCCT).
BSID can be run on either the
Eclipse Test Development environment or the ScanExecutive
Manufacturing test system. When a boundary-scan test fails,
BSID uses the diagostic failure data database generated by the ATPG module and the digital test results generated by the tester to isolate the failing devices, devicepins and the networks involved.
VIT tests can fail under a variety of
conditions. BSID diagnoses the following failure types. In all
cases, BSID clearly states the problem, lists all inputs and outputs
on the net, and identifies the failing detect points.
All inputs on a net are stuck either at a logic 1 or a logic 0. Typically, the problem is an open on the net or the net is shorted to power or ground.
Some inputs on a net are stuck either at a logic 1 or a logic 0. This condition typically results from an open on the part of the net that connects the stuck input(s).
Net is stuck either at a logic 1 or a logic 0 only when a particular driver is active. Most often, the problem is an open at the specified driver lead on a bus.
Shorts between nets
Common bridging faults between nets are clearly diagnosed Many testers and simulators accept truthby BSID regardless of whether a logic 1 or a logic 0 wins.
Strong driver short
Typically, a high current driver or a tester pin is shorted to some other net(s). The prob-lem is that the net with the strong driver never fails because it overdrives other net(s) involved in the short.
Faulty bidirectional pin
This failure type is typically caused by a blown input or output driver at the bidirectional pin. As a result, the boundary-scan output cell for the bidirectional pin drives the correct data onto the net but its associated boundary-scan input cell does not capture the correct value. Alternatively, the boundary-scan input cell captures the correct value from other drivers on the net, but its associated boundary-scan output cell is not able to drive the net.
Extended stuck-at faults
Leaky bus drivers can cause a test to fail by
overdriving the active driver on a bus. Shorts between boundary-scan
nets and non-boundary-scan nets. As part of an in-circuit test
program, BIT Plus patterns can detect shorts between boundary-scan
nets that have no tester access and non-boundary-scan nets with
To generate diagnostics for the internal connections of a virtual cluster test, BSID uses fault-dictionary techniques and must be supplied with a fault-dictionary database.
- Automatic diagnosis of VIT Eclipse ATPG and VCCT test failures
- Can be run on the tester or at an off-line repair station
- Currently available for Teradyne board test systems and Intellitech test systems
- Transportable to other test systems