FsmTest: Functional test generation for sequential circuits

This paper presents a new approach to test pattern generation for sequential circuits modeled as finite state machines. This approach is well suited for controller synthesis, because such devices are usually represented as explicit finite state machines. Based on a functional fault model, only a restricted set of transitions of the finite state machine (FSM) is considered for the purpose of testing. A new state discriminating sequence, referred to as EUIO is proposed. Overlapping is accomplished to reduce the test length. In most cases, test length and CPU time requirements are substantially lower compared with gate-level ATPGs. Techniques are also introduced to preserve a high fault coverage. Evaluation on MCNC benchmarks has shown the effectiveness of the test algorithm both at functional and gate levels, while achieving in most cases 100% coverage of single stuck-at faults.     

SystemC cosimulation and emulation of multiprocessor SoC designs

SystemC is an open source C/C++ simulation environment that provides several class packages for specifying hardware blocks and communication channels. The design environment specifies software algorithmically as a set of functions embedded in abstract modules that communicate with one another and with hardware components via abstract communication channels. It enables transparent integration of instruction-set simulators and prototyping boards. The authors describe a simulation environment that targets heterogeneous multiprocessor systems. They are currently working to extend their methodology to more complex on-chip architectures.     

FAST: An RTL Fault Simulation Framework based on RTL-to-TLM Abstraction

Functional verification techniques based on fault injection and simulation at register-transfer level (RTL) have been largely investigated in the past years. Although they have various advantages such as scalability and simplicity, they commonly suffer from the low speed of the cycle-accurate RTL simulation. On the other hand, Transaction-level modeling (TLM) allows a simulation speed sensibly faster than RTL. This article presents FAST, a framework to accelerate RTL fault simulation through automatic RTL-to-TLM abstraction. FAST abstracts RTL models injected with any RTL fault model into equivalent injected TLM models thus allowing a very fast fault simulation at TLM level. The article also presents FAST-DT, a new bit-accurate data type library integrated in the framework that allows a further improvement of the simulation speed-up. Finally, the article shows how the generated TLM test patterns can be automatically synthesized into RTL test patterns by exploiting the structural information of the RTL model extracted during the abstraction process. Experimental results have been performed on several designs of different size and complexity to show the methodology effectiveness.     

Identification of design errors through functional testing

Verification of the functionality of VHDL specifications is one of the primary and most time consuming tasks of design. However, it must necessarily be an incomplete task because it is impossible to completely exercise the specification by exhaustively applying all input patterns. We present a two-step strategy based on symbolic analysis of the VHDL specification, using a behavioral error model. First, we generate a reduced number of functional test vectors for each process of the specification by using a new analysis metric which we call bit coverage. The error model based on this metric allows the identification of possible design errors represented by redundancies in the VHDL code. Then, through the definition of a controllability measure, we verify if these functional test vectors can be applied to the process inputs when it is interconnected to other processes. If this is not the case, the analysis of the nonapplicable inputs provides identification of possible design errors due to erroneous interconnections. The bit-coverage provides complete statement, condition and branch coverage; and we experimentally show that it allows the identification of possible design errors. Identification and removal of design errors improves the global testability of a design.