Embedded logic analysis has emerged as a powerful technique for identifying functional bugs during post-silicon validation, as it enables at-speed acquisition of data from the circuit nodes in real-time. Nonetheless, the amount of data that is observed is limited by the capacity of the on-chip trace buffers. This paper introduces an automated method for improving the utilization of the on-chip storage, by identifying a small set of trace signals from which a large number of states can be restored using a compute-efficient algorithm. This enlarged set of data can then be used to aid the search of functional bugs in the fabricated circuit.
The size of on-chip trace buffers used for at-speed silicon debug limits the observation window in any debug session. Whenever the debug experiment can be repeated, we propose a novel architecture for at-speed silicon debug that enables a methodology where the designer can iteratively zoom only in the intervals containing erroneous samples. When compared to increasing the size of the trace buffer, the proposed architecture has a small impact on silicon area, while significantly reducing the number of debug sessions
22 February 2010 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
This paper investigates the application of computational methods via Satisfiability Modulo Theory (SMT) to the bit-width allocation problem for finite precision implementation of numerical calculations, specifically in the context of scientific computing where division frequently occurs. In contrast to the large body of work targeted at the precision aspect of the problem, this paper addresses the range problem where employing SMT leads to more accurate bounds estimation than those provided by other analytical methods, in turn yielding smaller bit-widths, and hence a reduction in hardware cost and/or increased parallelism, while maintaining robustness as is necessary for scientific applications.
21 October 2008 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Scan chain division has been successfully used to control shift power by enabling mutually exclusive flip-flops at different times during the scan cycle. However, to control capture power without losing transition fault coverage during at-speed scan test, the existing automatic test pattern generation (ATPG) flows need to be modified. In this paper, we present a novel scan chain division algorithm that analyzes the signal dependencies and creates the circuit partitions such that both shift and capture power can be reduced when using the existing ATPG flows. This novel algorithm has been designed for the broadside test application strategy, and a technique for employing partial scan when dividing the scan chains is also proposed.
Existing approaches for modular manufacturing test of core-based system-on-a-chip (SOC) devices do not provide any explicit mechanism for delivering two-pattern tests in the broadside mode, which is necessary to achieve reliable coverage of delay and stuck-open faults. Although wrapper input cells can be enhanced with two memory elements to address this problem, this incur a large test area overhead. This paper proposes a novel architecture for broadside two-pattern test of core-based SOCs without any loss in fault coverage and without increasing the size of the wrapper input cells. The proposed solution combines the dedicated bus-based test access mechanism and functional interconnects for test data transfer in order to provide full controllability of the wrapper input cells in the two consecutive clock cycles required by two-pattern testing. New algorithms for test access mechanism design and test scheduling are proposed and design trade-offs between test area and testing time are discussed using experimental results.
16 November 2012 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Lifetime performance of digital integrated circuits degrades as a consequence of circuit aging. In the past few years, there has been extensive research to reduce the impact of aging by different design techniques, or to predict the degradation and adapt the circuit accordingly. In this paper, we explore a novel perspective to this problem by exploiting the presence of clock tuning elements in high-performance designs. By combining on-chip sensors to predict setup or hold-time violations with the clock tuning elements, we provide an effective self-tuning mechanism for each circuit sample. The proposed method can operate in-system to prolong the circuit's maximum performance in its unique operating environment.