Conference Paper

Hierarchy-aware and area-efficient test infrastructure design for core-based system chips.

DOI: 10.1145/1131561 Conference: Proceedings of the Conference on Design, Automation and Test in Europe, DATE 2006, Munich, Germany, March 6-10, 2006
Source: DBLP

ABSTRACT Multiple levels of design hierarchy are common in current- generation system-on-chip (SOC) integrated circuits. However, most prior work on test access mechanism (TAM) optimization and test scheduling is based on a flattened design hierarchy. We investigate hierarchy-aware test infrastructure design, wherein wrapper/TAM optimization and test scheduling are carried out for hierarchical SOCs for two practical design scenarios. In the first scenario, the wrapper and TAM implementation for the em- bedded child cores in hierarchical (parent) cores are delivered in a hard form by the core provider. In the second scenario, the wrapper and TAM architecture of the child cores embedded in the parent cores are implemented by the system integrator. Ex- perimental results are presented for the ITC'02 SOC test bench- marks. test schedules designed for non-hierarchical SOCs are typically not valid for SOCs with hierarchical cores. The hierarchy im- poses a number of constraints on the manner in which tests must be applied to parent cores and their embedded child cores (8); hierarchy-oblivious methods make no attempt to satisfy these constraints. In this paper, we describe a test infrastructure design approach for hierarchical SOCs; our approach is based on hierarchy-aware wrapper design for parent cores, TAM optimization techniques for the SOC and the parent cores, and chip-level test scheduling. We consider two different test infrastructure design scenarios. In Scenario 1, we assume that the wrappers and TAM architectures for the child cores are given and fixed (hard), while the wrappers and TAM architectures for the parent cores are to be determined by our approach (soft). In Scenario 2, the wrapper and TAM for both parent and child cores are assumed to be soft. The sequel of this paper is organized as follows. In Section 2, we review the limitations of prior work. In Section 3, we discuss various DfT techniques that can be used to reduce test length. Section 4 describes our approach for Scenario 1, while Section 5 addresses Scenario 2. We derive lower bounds on the test time in Section 6. In Section 7, we present test application times and lower bounds for the ITC'02 SOC test benchmarks (5). Finally, Section 8 concludes the paper.

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