Self-test Logic Research Articles

Tolerating Permanent Faults in the Input Port of the Network on Chip Router

Deep submicron technologies continue to develop according to Moore’s law allowing hundreds of processing elements and memory modules to be integrated on a single chip forming multi/many-processor systems-on-chip (MPSoCs). Network on chip (NoC) arose as an interconnection for this large number of processing modules. However, the aggressive scaling of transistors makes NoC more vulnerable to both permanent and transient faults. Permanent faults persistently affect the circuit functionality from the time of their occurrence. The router represents the heart of the NoC. Thus, this research focuses on tolerating permanent faults in the router’s input buffer component, particularly the virtual channel state fields. These fields track packets from the moment they enter the input component until they leave to the next router. The hardware redundancy approach is used to tolerate the faults in these fields due to their crucial role in managing the router operation. A built-in self-test logic is integrated into the input port to periodically detect permanent faults without interrupting router operation. These approaches make the NoC router more reliable than the unprotected NoC router with a maximum of 17% and 16% area and power overheads, respectively. In addition, the hardware redundancy approach preserves the network performance in the presence of a single fault by avoiding the virtual channel closure.

A Cache Architecture for Extremely Unreliable Nanotechnologies

In the drive to create ever smaller transistors, conventional silicon CMOS devices are becoming more difficult to fabricate reliably as process size shrinks. New technologies are being investigated to replace silicon CMOS. While offering greater numbers of devices per unit area, all of these technologies are more difficult to fabricate, and more likely to fail in operation than current technologies. Nanotechnology research has identified the need for fault and defect tolerance at the architectural level so that future devices can be used in large-scale electronics circuits. This paper examines the problem of creating reliable caches using extremely unreliable technologies. We incorporate support logic (i.e., control, datapath, and self-test logic) into the analysis, and propose a novel Content Addressable Memory-based design incorporating best practice fault tolerant design techniques. The design requires 15 times the number of devices of a conventional design, but enables the use of device technologies with defect rates higher than 10-6, a three order of magnitude improvement over non-fault tolerant designs

A true single-phase energy-recovery multiplier

In this paper, we present the design and experimental evaluation of an 8-bit energy-recovery multiplier with built-in self-test logic and an internal single-phase sinusoidal power-clock generator. Both the multiplier and the built-in self-test have been designed in SCAL-D, a true single-phase adiabatic logic family. Fabricated in a 0.5-/spl mu/m standard n-well CMOS process, the chip has an active area of 0.47 mm/sup 2/. Correct chip operation has been verified for clock rates up to 140 MHz. Moreover, chip dissipation measurements correlate well with HSPICE simulation results. For a selection of biasing conditions that yield correct operation at 140 MHz, total measured average dissipation for the multiplier and the power-clock generator is 250 pJ per operation.

Low-cost testing of high-density logic components

The evolution of a testing method and architecture of a logic-device tester to be used for the next generation of IBM's high-density CMOS ASIC (application-specific integrated circuit) logic components is described. The tester's design is based on the architecture of an existing IBM memory tester rather than on a conventional logic-tester design. The testing strategy calls for boundary-scan in each component design, built-in self-test logic within embedded memory arrays, and the use of weighted random-pattern logic testing. The development of the tester hardware is discussed, and capital costs of the new tester are compared with those of other approaches.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>