Hierarchical test generation and design for testability methods for ASPPs and ASIPs
01 Mar 1999-IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (IEEE)-Vol. 18, Iss: 3, pp 357-370
TL;DR: The method utilizes the register-transfer level (RTL) circuit description of an ASPP or ASIP to come up with a set of test microcode patterns which can be written into the instruction read-only memory (ROM) of the processor.
Abstract: In this paper, we present design for testability (DFT) and hierarchical test generation techniques for facilitating the testing of application-specific programmable processors (ASPPs) and application-specific instruction processors (ASIPs). The method utilizes the register-transfer level (RTL) circuit description of an ASPP or ASIP to come up with a set of test microcode patterns which can be written into the instruction read-only memory (ROM) of the processor. These lines of microcode dictate a new control/data flow in the circuit and can be used to test modules which are not easily testable. The new control/data flow is used to justify precomputed test sets of a module from the system primary inputs to the module inputs and propagate output responses from the module output to the system primary outputs. The testability analysis, which is based on the relevant control/data flow extracted from the RTL circuit, is symbolic. Thus, it is independent of the bit-width of the data path and is extremely fast. The test microcode patterns are a by-product of this analysis. If the derived test microcode cannot test all untested modules in the circuit, then test multiplexers are added (usually to the off-critical paths of the data path) to test these modules. This is done to guarantee the testability of all modules in the circuit. If the control microcode memory of the processor is erasable, then the test microcode lines can be erased once the testing of the chip is over. In that case, the DFT scheme has very little overhead (typically less than 1%). Otherwise, the test microcode lines remain as an overhead in the control memory. The method requires the addition of only one external test pin. Application of this technique to several examples has resulted in a very high fault coverage (above 99.6%) for all of them. The test generation time is about three orders of magnitude smaller compared to an efficient gate-level sequential test generator. The average area overhead (without assuming an erasable ROM) is 3.1% while the delay overheads are negligible. This method does not require any scan in the controller or data path. It is also amenable to at-speed testing.
Citations
More filters
Patent•
28 Jun 2001TL;DR: In this paper, the authors present a change item definition information concerning system LSI development and design, software used for development and the design of a system-LSI that contains a processor having optional instructions defined therein.
Abstract: In this disclosure, based on change item definition information concerning system LSI development and design, software used for development and design of a system LSI that contains a processor having optional instructions defined therein is operated, and system LSI hardware description, verification environment and a development and design tools are generated, thus making it possible to develop a system LSI optimal to an application within a short period.
48 citations
TL;DR: A comprehensive framework that generates low-overhead compact test solutions for SOCs and introduces finite-state automata (FSA) for modeling tests, transparency modes, and testing hardware behavior is provided.
Abstract: Available techniques for testing of core-based systems-on-a-chip (SOCs) do not provide a systematic means for synthesizing low-overhead test architectures and compact test solutions. In this paper, we provide a comprehensive framework that generates low-overhead compact test solutions for SOCs. First, we develop a common ground for addressing issues such as core test requirements, core access, and testing hardware additions. For this purpose, we introduce finite-state automata (FSA) for modeling tests, transparency modes, and testing hardware behavior. In many cases, the tests repeat a basic set of test actions for different test data that can again be modeled using FSA. While earlier work can derive a single symbolic test for a module in a register-transfer level (RTL) circuit as a finite-state automaton, this work extends the methodology to the system level and additionally contributes a satisfiability-based solution to the problem of applying a sequence of tests phased in time. This problem is known to be a bottleneck in testability analysis not only at the system level, but also at the RTL. Experimental results show that the system-level average area overhead for making SOCs testable with our method is only 4.5%, while achieving an average test application time reduction of 80% over recent approaches. At the same time, it provides 100% test coverage of the precomputed test sets/sequences of the embedded cores.
45 citations
TL;DR: Experimental results on benchmark circuits show that TAO is very efficient, in addition to being comprehensive, and a design-for-test (DFT) framework that can provide a low-cost testability solution by examining the tradeoffs in choosing from a diverse array of testability modifications like partial scan or test multiplexer insertion in different parts of the circuit.
Abstract: In this paper, we present testability analysis and optimization (TAO), a novel methodology for register-transfer level (RTL) testability analysis and optimization of RTL controller/data path circuits. Unlike existing high-level testing techniques that cater restrictively to certain classes of circuits or design styles, TAO exploits the algebra of regular expressions to provide a unified framework for handling a wide variety of circuits including application-specific integrated circuits (ASICs), application-specific programmable processors (ASPPs), application-specific instruction processors (ASIPs), digital signal processors (DSPs), and microprocessors. We also augment TAO with a design-for-test (DFT) framework that can provide a low-cost testability solution by examining the tradeoffs in choosing from a diverse array of testability modifications like partial scan or test multiplexer insertion in different parts of the circuit. Test generation is symbolic and, hence, independent of bit width. Experimental results on benchmark circuits show that TAO is very efficient, in addition to being comprehensive. The fault coverage obtained is above 99% in all cases. The average area and delay overheads for incorporating testability into the benchmarks are only 3.2% and 1.0%, respectively. The test generation time is two-to-four orders of magnitude smaller than that associated with gate-level sequential test generators, while the test application times are comparable.
37 citations
28 Jan 2000
TL;DR: This paper presents a non-scan design-for-testability (DFT) method for VLSIs designed at register transfer level (RTL) to achieve complete fault efficiency and results show that the proposed method can reduce significantly both of test generation time and test application time compared with the full- scan design.
Abstract: This paper presents a non-scan design-for-testability (DFT) method for VLSIs designed at register transfer level (RTL) to achieve complete fault efficiency. In RTL design, a VLSI generally consists of a controller and a data path. The controller and the data path are connected with internal signals: control signals and status signals. The proposed method consists of the following two steps. First, we apply our DFT methods to the controller and the data path, respectively. Then, to support at-speed testing, we append a test plan generator which generates a sequence of test control vectors for the modified data path. Our experimental results show that the proposed method can reduce significantly both of test generation time and test application time compared with the full-scan design, though the hardware overhead of our method is slightly larger than that of the full-scan design.
32 citations
Cites background from "Hierarchical test generation and de..."
...Genesis [12]–[15] is an approach based on such hierarchical test generation for data paths....
[...]
TL;DR: This paper presents a satisfiability (SAT)-based algorithm for automatically generating test sequences that target gate-level stuck-at faults in a circuit by using its register-transfer level (RTL) description, and shows that this RTL test generator can outperform gate- level sequential automatic test-pattern generation (ATPG), in terms of both fault coverage and test-generation time.
Abstract: In this paper, we present a satisfiability (SAT)-based algorithm for automatically generating test sequences that target gate-level stuck-at faults in a circuit by using its register-transfer level (RTL) description. Our methodology uses a unified RTL circuit representation, called assignment-decision diagrams (ADDs), for test analysis. Test generation proceeds by abstracting the components in this unified representation using input/output propagation rules, so that any justification/propagation event can be captured as a Boolean implication. Consequently, we reduce RTL test generation to an SAT instance that has a significantly lower complexity than the equivalent problem at the gate level. Our algorithm is tailored to overcome the disadvantages of several existing RTL precomputed test-set-based approaches, such as the need for an explicit controller/datapath separation, the use of all test vectors or none from the precomputed test set for any given module, a dependence on symbolic justification (observability) paths from (to) circuit inputs (outputs) for a module, and a lack of applicability to mixed gate-level/RTL designs. Using the state-of-the-art SAT solver Zchaff, we show that our RTL test generator can outperform gate-level sequential automatic test-pattern generation (ATPG), in terms of both fault coverage and test-generation time (two-to-three orders of magnitude speedup), in comparable test-application times. Furthermore, we show that in a bilevel testing scenario, in which RTL ATPG is followed by gate-level sequential ATPG on the remaining faults, we improve the fault coverage even further, while maintaining a high speedup in test-generation time (nearly 32/spl times/) over pure gate-level sequential ATPG, at comparable test-application times.
30 citations
References
More filters
25 Feb 1991
TL;DR: HITEC is presented, a sequential circuit test generation package to generate test patterns for sequential circuits, without assuming the use of scan techniques or a reset state, and several new techniques are introduced to improve the performance of test generation.
Abstract: This paper presents HITEC, a sequential circuit test generation package to generate test patterns for sequential circuits, without assuming the use of scan techniques or a reset state Several new techniques are introduced to improve the performance of test generation A targeted D element technique is presented, which greatly increases the number of possible mandatory assignments and reduces the over-specification of state variables which can sometimes result when using a standard PODEM algorithm A technique to use the state knowledge of previously generated vectors for state justification, without the memory overhead of a state transition diagram is presented For faults that were aborted during the standard test generation phase, knowledge that was gained about fault propagation, by the fault simulator, is used These techniques, when used together, produce the best published results for the ISCAS89 sequential benchmark circuits
673 citations
"Hierarchical test generation and de..." refers methods in this paper
...We compare the performance of our method against HITEC [ 37 ], an efficient gate-level sequential test generator....
[...]
11 Oct 1992
TL;DR: SIS serves as both a framework within which various algorithms can be tested and compared and as a tool for automatic synthesis and optimization of sequential circuits.
Abstract: A description is given of SIS, an interactive tool for synthesis and optimization of sequential circuits. Given a state transition table or a logic-level description of a sequential circuit, SIS produces an optimized net-list in the target technology while preserving the sequential input-output behavior. Many different programs and algorithms have been integrated into SIS, allowing the user to choose among a variety of techniques at each stage of the process. It is built on top of MISII and includes all (combinational) optimization techniques therein as well as many enhancements. SIS serves as both a framework within which various algorithms can be tested and compared and as a tool for automatic synthesis and optimization of sequential circuits. >
551 citations
"Hierarchical test generation and de..." refers methods in this paper
...The testing of the controller was handled separately as the controller consists of a ROM which is neither supported by SIS [ 33 ], the logic synthesis tool that we used, nor the fault simulation tool PROOFS [34] available to us. Part of the overhead calculation for the controller part of the circuit had to be done manually using instruction ROM’s generated by the ALLIANCE synthesis system [35]....
[...]
TL;DR: In this paper, a general graph-theoretic model is developed at the register transfer level which takes the microprocessor organization and the instruction set as parameters and generate tests to detect all the faults in the fault model.
Abstract: The goal of this paper is to develop test generation procedures for testing microprocessors in a user environment. Classical fault detection methods based on the gate and flip-flop level or on the state diagram level description of microprocessors are not suitable for test generation. The problem is further compounded by the availability of a large variety of microprocessors which differ widely in their organization, instruction repertoire, addressing modes, data storage, and manipulation facilities, etc. In this paper, a general graph-theoretic model is developed at the register transfer level. Any microprocessor can be easily modeled using information only about its instruction set and the functions performed. This information is readily available in the user's manual. A fault model is developed on a functional level quite independent of the implementation details. The effects of faults in the fault model are investigated at the level of the graph-theoretic model. Test generation procedures are proposed which take the microprocessor organization and the instruction set as parameters and generate tests to detect all the faults in the fault model. The complexity of the test sequences measured in terms of the number of instructions is given. Our effort in generating tests for a real microprocessor and evaluating their fault coverage is described.
380 citations
TL;DR: Experimental results obtained by adding the proposed heuristics to a simple PODEM procedure and applying it to the ISCas-85 and fully-scanned ISCAS-89 benchmark circuits are presented to substantiate the effectiveness of the proposedHeuristics.
Abstract: Heuristics to aid the derivation of small test sets that detect single stuck-at faults in combinational logic circuits are proposed. The heuristics can be added to existing test pattern generators without compromising fault coverage. Experimental results obtained by adding the proposed heuristics to a simple PODEM procedure and applying it to the ISCAS-85 and fully-scanned ISCAS-89 benchmark circuits are presented to substantiate the effectiveness of the proposed heuristics. >
332 citations
01 Jun 1995
TL;DR: Important themes covered by the book include: the scope of general purpose versus application-specific processors, machine code quality for embedded applications, retargetability of the code generation process, machine description formalisms, and code generation methodologies.
Abstract: From the Publisher:
Modern electronics is driven by the explosive growth of digital communications and multi-media technology. A basic challenge is to design first-time-right complex digital systems, that meet stringent constraints on performance and power dissipation. In order to combine this growing system complexity with an increasingly short time-to-market, new system design technologies are emerging based on the paradigm of embedded programmable processors. This concept introduces modularity, flexibility and re-use in the electronic system design process. However, its success will critically depend on the availability of efficient and reliable CAD tools to design, programme and verify the functionality of embedded processors. Recently, new research efforts emerged on the edge between software compilation and hardware synthesis, to develop high-quality code generation tools for embedded processors. Code Generation for Embedded Processors provides a survey of these new developments. Although not limited to these targets, the main emphasis is on code generation for modern DSP processors. Important themes covered by the book include: the scope of general purpose versus application-specific processors, machine code quality for embedded applications, retargetability of the code generation process, machine description formalisms, and code generation methodologies. Code Generation for Embedded Processors is the essential introduction to this fast developing field of research for students, researchers, and practitioners alike.
235 citations
"Hierarchical test generation and de..." refers methods in this paper
...Fig. 12 shows the RTL circuit of an ASIP named SimpleCPU, which we have taken from [ 30 ] and modified slightly to give it a little more functionality....
[...]