UBC Theses and Dissertations
Testability infrastructure for Systems-on-Chip Nahvi, Mohsen
Relying on external automatic test equipment (ATE) resources is insufficient for the new paradigm of billion-transistor core-based System-on-Chip (SoC) designs. Embedded testers that take over some functionality of these ATEs are increasingly deemed essential. To achieve high-quality test and reduce cost, these embedded infrastructures need to perform deterministic tests and exploit the advantages of automatic test pattern generation (ATPG) test vector sets. This thesis proposes an embedded testing infrastructure that leverages the potentials of the classical embedded testing in the form of Built-in Self-Test (BIST). However, unlike BIST, the methodology of this thesis is based on the conventional scan/ATPG approach. This novel methodology partitions test resources to embed the test application and test results analysis on-chip while keeping the ATPG test vector files off-chip. The proposed infrastructure was implemented on silicon and experimental area and test time results are reported. Using the methodology of this thesis, a high-quality deterministic test, with reduced overall test time through ideal multi-site testing, can be achieved. Modular, flexible, and systematic test architectures are also deemed essential in SoC tests. The conventional testing paradigm requires a direct connection between a tester and the circuit under test (CUT). This arrangement undermines the modularity in the test architecture by tightly coupling its elements. This thesis proposes to de-couple test data processing and communication to lower test cost. To that end, a novel systematic and indirect test architecture that is based on network-oriented protocols is proposed. In this new architecture, test stimuli and expected results for digital cores are formatted into new protocols and then encapsulated into packets. These packets are augmented with control and address bits allowing them to be autonomously transmitted to their destination through a switching infrastructure. Finally, embedded autonomous blocks at each core are used for applying the test and comparing the results. In this way, the methodology of this thesis facilitates test cycle automation and eliminates the need for control lines. This results in better utilisation of available resources. A first implementation of this new architecture and its area and test time impact are presented.
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