Virtual Component /Cluster Test (VCCT)

The VCCT module serializes parallel test patterns so that they can be applied through the boundary scan pathThe VCCT module serializes parallel test patterns so that they can be applied through the boundary scan path to detect manufacturing faults on non-scan logic surrounded by boundary scan devices. VCCT can be used to test an individual non-scan component – such as a memory device – or a cluster of non-scan devices. VCCT can also apply a combination of serial and parallel test patterns to test the non-scan logic. When both serial and parallel test patterns are used, VCCT automatically synchronizes the application of serial patterns at scan cells with parallel patterns at the ParallelRiter™ card or tester channels.
VCCT patterns can also be applied through the ParallelRiter™ card to test and assembly’s I/O pins.
VCCT uses the scan cells of boundary-scan devices as virtual channels to drive stimuli into the non-scan logic devices or clusters and detect responses from them. Stimulus patterns are conventional parallel test patterns which, VCCT regenerates into a serial format to apply via the boundary-scan path. Patterns for component test may be available from an in-circuit test library, a design pattern library, or they may have to be generated manually.
VCCT testing includes the following capabilities:
  • Detection of open and stuck-at faults on non-scan devices or clusters of non-scan devices using the scan chain
  • Elimination of physical access requirements for testing conventional parts surrounded by boundary scan devices
  • Automatic analysis to identify stimulus and measurement points for components
  • Automatic serialization of parallel patterns to test non-scan devices or clusters
  • Synchronous application of serial test patterns through the boundary-scan cells and parallel test patterns through the ParallelRiter™ card or in-circuit test channels
The VCCT module serializes parallel test patterns so that they can be applied through the boundary scan path
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