[previous] [next] [contents]    Synchronisation with external test resources
The test protocol for full-BS interconnects and non-BS clusters, described in the previous chapter, made it clear that testing interconnects or clusters associated with cells from different BS chains, or with primary I/O pins of the PCB, require a co-ordinated procedure to complete test vector application from all driving pins, before the responses start to be captured. A synchronisation protocol is required when co-ordinating the BS infrastructure and the external test resources, which may be implemented by a simple handshake procedure for test vector application and response capturing on both sides, based on a sync output and a sync input and leading to the following basic test operations:
  • Set the sync output to a pre-defined logic value (0 or 1).
The BS test controller will set the sync output to notify the external test equipment that the application of the test vector through the BS infrastructure is finalised and will reset it to notify that all test responses were captured through the BS infrastructure.
  • Wait until the sync input is set to a pre-defined logic value (0 or 1).
Following the application of each test vector through the BS infrastructure and its notification through the sync output, the BS test controller will wait for notification from the external test equipment (that the external test stimuli were applied as well) before capturing any responses. Similarly, after concluding the response capturing phase, the BS test controller will wait for notification from the external test equipment (that response capturing was finalised there as well), before initiating the application of the next test vector.