Studies on Core-Based Testing of System-on-Chips Using Functional Bus and Network-on-Chip Interconnects

The tests of a complex system such as a microprocessor-based system-onchip (SoC) or a network-on-chip (NoC) are difficult and expensive. In this thesis, we propose three core-based test methods that reuse the existing functional interconnects-a flat bus, hierarchical buses of multiprocessor SoC's (MPSoC), and a N oC-in order to avoid the silicon area cost of a dedicated test access mechanism (TAM). However, the use of functional interconnects as functional TAM's introduces several new problems. During tests, the interconnects-including the bus arbitrator, the bus bridges, and the NoC routers-operate in the functional mode to transport the test stimuli and responses, while the core under tests (CUT) operate in the test mode. Second, the test data is transported to the CUT through the functional bus, and not directly to the test port. Therefore, special core test wrappers that can provide the necessary control signals required by the different functional interconnect are proposed. We developed two types of wrappers, one buffer-based wrapper for the bus-based systems and another pair of complementary wrappers for the NoCbased systems. Using the core test wrappers, we propose test scheduling schemes for the three functionally different types of interconnects. The test scheduling scheme for a flat bus is developed based on an efficient packet scheduling scheme that minimizes both the buffer sizes and the test time under a power constraint. The schedulingscheme is then extended to take advantage of the hierarchical bus architecture of the MPSoC systems. The third test scheduling scheme based on the bandwidth sharing is developed specifically for the NoC-based systems. The test scheduling is performed under the objective of co-optimizing the wrapper area cost and the resulting test application time using the two complementary NoC wrappers. For each of the proposed methodology for the three types of SoC architec .. ture, we conducted a thorough experimental evaluation in order to verify their effectiveness compared to other methods

NASA preprototype redox storage system for a photovoltaic stand-alone application

A 1 kW preprototype redox storage system underwent characterization tests and was operated as the storage device for a 5 kW (peak) photovoltaic array. The system is described and performance data are presented. Loss mechanisms are discussed and simple design changes leading to significant increases in efficiency are suggested. The effects on system performance of nonequilibrium between the predominant species of complexed chromic ion in the negative electrode reactant solution are indicated

Reconfigurable multiple scan-chains for reducing test application time of SOCs

[[abstract]]We propose an algorithm, based on a framework of reconfigurable multiple scan-chains for a system-on-chip, to minimize test application time. For the framework, the control signal combination causes the computing time to increase exponentially. The algorithm we propose introduces a heuristic control signal selection method to solve this problem. We also minimize the test application time by using the balancing method to assign registers into multiple scan-chains. It could show significant reductions in test application times and computing times.[[conferencetype]]國際[[conferencedate]]20050523~20050526[[conferencelocation]]Kobe, Japa

Optimal Test Access Mechanism (TAM) for Reducing Test Application Time of Core-Based SOCs

[[abstract]]In this paper, we propose an algorithm based on a framework of reconfigurable multiple scan chains for system-on-chip to minimize test application time. The control signal combination causes the computing time increasing exponentially, and the algorithm we proposed introduces a heuristic control signal selecting method to solve this serious problem. We also minimize the test application time by using the balancing method to assign registers into multiple scan chains. The results show that it could significantly reduces both the test application time and the computation time.[[notice]]補正完畢[[incitationindex]]EI[[booktype]]紙

Design of Dynamically Assignmentable TAM Width for Testing Core-Based SOCs

[[abstract]]Test access mechanism (TAM) and testing schedule for system-on-chip (SOC) are challenging problems. Testing schedule must be effective to minimize testing time, under the constraint of test resources. This paper presents a new method based on generalized rectangle packing, as two-dimensional packing. A core cuts into many pieces and utilizes the design of reconfigurable core wrappers, and is dynamic to change the width of the TAM executing the core test. Therefore, a core can utilize different TAM width to complete test[[conferencetype]]國際[[conferencedate]]20061204~20061207[[iscallforpapers]]Y[[conferencelocation]]Singapor