一种基于FPGA的微处理器软错误敏感性分析方法

为了自动快速地分析微处理器对软错误的敏感性,该文提出一种基于FPGA故障注入的软错误敏感性分析方法。在FPGA芯片上同时运行有故障和无故障的两个微处理器,并充分利用FPGA的并行性,把故障注入控制、故障分类、故障列表等模块均在硬件上实现,自动快速地完成全部存储位的故障注入。以PIC16F54微处理器为实验对象,基于不同负载分别注入约30万个软错误用以分析微处理器软错误敏感性,并对敏感性较高的单元加固后再次进行分析,验证该方法的有效性。实验数据表明,使用该方法进行故障注入及敏感性分析所需的时间比软件仿真方法提高了4个数量级。     

Soft errors in floating gate memory cells: A review

Soft errors due to neutrons and alpha particles are among the main threats for the reliability of digital circuits operating at terrestrial level. These kinds of errors are typically associated with SRAMs and latches or DRAMs, and less frequently with non-volatile memories. In this paper we review the studies on the response of NAND and NOR Flash memories to ionizing particles, focusing on both single-level and multi-level cell architectures, manufactured in technologies down to a feature size of 25 nm. We discuss experimental error rates obtained with accelerated tests and identify the relative importance of neutron and alpha contributions. Technology scaling trends are finally discussed and modelled.     

复杂数字电路中的单粒子效应建模综述

单粒子效应产生的软错误是影响航天电子系统可靠性的主要因素之一。对其进行建模是研究单粒子效应机理和电路加固技术的有效方法。介绍了深亚微米及以下工艺中影响模型准确性的几种效应机制,包括脉冲展宽机制、电荷共享机制和重汇聚机制等。重点分析了单粒子瞬态、单粒子翻转的产生模型和单粒子瞬态的传播模型。阐述了基于重离子和脉冲激光的模型验证方法。最后,分析了单粒子效应随特征尺寸的变化趋势,并提出了未来单粒子效应建模技术的发展方向。     

基于C单元反馈回路的容SEU锁存器设计

随着电子技术的不断发展,集成电路的特征尺寸不断缩小,导致电路对宇宙高能粒子引发的单粒子翻转愈发敏感。提出了一种对单粒子翻转完全免疫的抗辐射加固锁存器。该锁存器利用具有过滤功能的C单元构建反馈回路,并在锁存器末端使用钟控C单元来阻塞传播至输出端的软错误。HSPICE仿真结果显示,在与TMR锁存器同等可靠性的情况下,该锁存器面积下降50%,延迟下降92%,功耗下降47%,功耗延迟积下降96%。     

A low power-delay-product and robust Isolated-DICE based SEU-tolerant latch circuit design

Soft-error interference is a crucial design challenge in the advanced CMOS VLSI circuit designs. In this paper, we proposed a SEU Isolating DICE latch (Iso-DICE) design by combing the new proposed soft-error isolating technique and the inter-latching technique used in the DICE (Calin et al., 1996 [1]) design. To further enhance SEU-tolerance of DICE design, we keep the storage node pairs having the ability to recover the SEU fault occurring in each other pair but also avoid the storage node to be affected by each other. To mitigate the interference effect between dual storage node pairs, we use the isolation mechanism to resist high energy particle strikes instead of the original interlocking design method. Through isolating the output nodes and the internal circuit nodes, the Iso-DICE latch can possess more superior SEU-tolerance as compared with the DICE design (Calin et al., 1996 [1]). As compared with the FERST design (Fazeli, 2009 [2]) which performs with the same superior SEU-tolerance, the proposed Iso-DICE latch consumes 50% less power with only 45% of power delay product in TSMC 90 nm CMOS technology. Under 22 nm PTM model, the proposed Iso-DICE latch can also perform with 11% power delay product saving as compared with the FERST design (Fazeli, 2009 [2]) that performs with the same superior SEU-tolerance.     

一种容SEU的新型自恢复锁存器

针对单粒子翻转(SEU)的问题,提出了一种容SEU的新型自恢复锁存器。采用1P-2N单元、输入分离的钟控反相器以及C单元,使得锁存器对SEU能够实现自恢复,可用于时钟门控电路。采用高速通路设计和钟控设计,以减小延迟和降低功耗。相比于HLR-CG1,HLR-CG2,TMR,HiPer-CG锁存器,该锁存器的功耗平均下降了44.40%,延迟平均下降了81%,功耗延迟积(PDP)平均下降了94.20%,面积开销平均减少了1.80%。     

一种低开销加固锁存器的设计

针对单粒子翻转问题,设计了一种低开销的加固锁存器。在输出级使用钟控C单元,以屏蔽锁存器内部节点的瞬态故障;在输出节点所在的反馈环上使用C单元,屏蔽输出节点上瞬态故障对电路的影响;采用了从输入节点到输出节点的高速通路设计,延迟开销大幅降低。HSPICE仿真结果表明,相比于FERST,SEUI,HLR,Iso-DICE锁存器,该锁存器的面积平均下降23.20%,延迟平均下降55.14%,功耗平均下降42.62%。PVT分析表明,该锁存器的性能参数受PVT变化的影响很小,性能稳定。     

一种针对软错误的程序可靠性定量分析方法

 宇宙射线辐射所导致的软错误是航天计算面临的最主要挑战之一.而随着集成电路制造工艺的持续进步,现代处理器的计算可信性日益面临着软错误的严重威胁.当前,很少有研究从软件角度分析软错误对系统可靠性的影响.在程序汇编代码的基础上,提出一种针对软错误的程序可靠性定量分析方法PRASE,并且提出基本块分析法和3条运算定律以改进其分析效率.实验表明软错误对程序可靠性的影响与程序自身结构密切相关,同时分析结果还指出在软错误影响下程序的关键脆弱点,对实现针对软错误的高效容错算法有参考意义.     

Assessing the Soft Error Rate of Digital Architectures Devoted to Operate in Radiation Environment: A Case Studied

The effects of transient bit flips on the operation of processor based architectures is investigated through fault injection experiments performed in the hardware itself by means of the interruption mechanism. Such an approach is based on the execution, as the consequence of an interruption signal assertion, of pieces of code called CEU (Code Emulating Upsets), asynchronously downloaded in a suitable memory area. This paper focuses in the methodology followed to set-up CEU injection experiments on a digital architecture, illustrating it main steps by means of a studied case: the 80C51 microcontroller. Results obtained from automated fault injection sessions performed using the capabilities of a devoted test system, will point out the capabilities and limitations of the studied approach.     

基于码流的软件控制FPGA故障注入系统

基于静态随机存储器的现场可编程逻辑门阵列应用于航天电子系统时,易受到单粒子翻转效应的影响,存储数据会发生损坏。为评估器件和电路在单粒子翻转效应下的可靠性,提出一种基于TCL脚本控制的故障注入系统,可在配置码流层面模拟单粒子翻转效应。介绍了该故障注入系统的实现机制和控制算法,并将该软件控制方法与传统硬件控制方法进行对比分析。设计了一种关键位故障模型,从设计网表中提取关键位的位置信息,缩小了故障注入的码流范围。在Virtex-5开发板XUPV5-LX110T上的故障注入实验表明,该故障注入系统能有效模拟单粒子翻转效应,与传统随机位故障注入相比,关键位故障注入的故障率提高了近5倍。     

Soft error estimation and mitigation of digital circuits by characterizing input patterns of logic gates

Soft errors caused by particles strike in combinational parts of digital circuits are a major concern in the design of reliable circuits. Several techniques have been presented to protect combinational logic and reduce the overall circuit Soft Error Rate (SER). Such techniques, however, typically come at the cost of significant area and performance overheads. This paper presents a low area and zero-delay overhead method to protect digital circuits’ combinational parts against particles strike. This method is made up of a combination of two sub-methods: (1) a SER estimation method based on signal probability, called Estimation by Characterizing Input Patterns (ECIP) and (2) a protection method based on gate sizing, called Weighted and Timing Aware Gate Sizing (WTAGS). Unlike the previous techniques that either overlook internal nodes signal probability or exploit fault injection, ECIP computes the sensitivity of each gate by analytical calculations of both the probability of transient pulse generation and the probability of transient pulse propagation; these calculations are based on signal probability of the whole circuit nodes which make ECIP much more accurate as well as practical for large circuits. Using the results of ECIP, WTAGS characterizes the most sensitive gates to efficiently allocate the redundancy budget. The simulation results show the SER reduction of about 40% by applying the proposed method to ISCAS’89 benchmark circuits while imposing no delay overhead and 5% area overhead.     

Node-to-node error sensitivity analysis using a graph based approach for VLSI logic circuits

Shrinking the transistors size and supply voltage in the advanced VLSI logic circuits, significantly increases the susceptibility of the circuits to soft errors. Therefore, analysis of the effects on other nodes, caused by the soft errors occurring at each individual node is an essential step for VLSI logic circuit design. In this paper, a novel approach based on the Mason’s gain formula, for the node-to-node sensitivity analysis of logic circuits is proposed. Taking advantage of matrix sparsity, the runtime and the memory requirement of the proposed approach become scalable. Also, taking the effects of reconvergent paths into account, the accuracy of the proposed approach is improved considerably. According to the simulation results, the proposed approach runs 4.7× faster than those proposed in the prior works while its computational complexity is O(N^1.07) on the average.     

基于四值脉冲参数模型的单粒子瞬态传播机理与软错误率分析方法

随着工艺尺寸的不断缩小,由单粒子瞬态(Single Event Transient, SET)效应引起的软错误已经成为影响宇航用深亚微米VLSI电路可靠性的主要威胁,而SET脉冲的产生和传播也成为电路软错误研究的热点问题。通过研究SET脉冲在逻辑链路中的传播发现：脉冲上升时间和下降时间的差异能够引起输出脉冲宽度的展宽或衰减;脉冲的宽度和幅度可决定其是否会被门的电气效应所屏蔽。该文提出一种四值脉冲参数模型可准确模拟SET脉冲形状,并采用结合查找表和经验公式的方法来模拟SET脉冲在电路中的传播过程。该文提出的四值脉冲参数模型可模拟SET脉冲在传播过程中的展宽和衰减效应,与单参数脉冲模型相比计算精度提高了2.4%。该文应用基于图的故障传播概率算法模拟SET脉冲传播过程中的逻辑屏蔽,可快速计算电路的软错误率。对ISCAS89及ISCAS85电路进行分析的实验结果表明：该方法与HSPICE仿真方法的平均偏差为4.12%,计算速度提升10000倍。该文方法可对大规模集成电路的软错误率进行快速分析。     

MPEG-2视频信号错误控制和错误掩盖技术

以ＭＰＥＧ－２的语法规范作基础,从控制错误发生和控制错误传播的角度,简述了ＭＥＰＧ－２的分级工具和视频码流层结构,比较详细地介绍了Ｉ帧、Ｐ帧和Ｂ帧的错误掩盖技术,此外,还推荐了一些错误掩盖方法。     

低功耗容软错误的65 nm CMOS 12管SRAM单元

提出了一种具有软错误自恢复能力的12管SRAM单元。该单元省去了专用的存取管,具有高鲁棒性、低功耗的优点。在65 nm CMOS工艺下,该结构能够完全容忍单点翻转,容忍双点翻转的比例是64.29%,与DICE加固单元相比,双点翻转率降低了30.96%。与DICE、Quatro等相关SRAM加固单元相比,该SRAM单元的读操作电流平均下降了77.91%,动态功耗平均下降了60.21%,静态电流平均下降了44.60%,亚阈值泄漏电流平均下降了27.49%,适用于低功耗场合。     

High performance energy efficient radiation hardened latch for low voltage applications

Energy efficiency is considered to be the most critical design parameter for IoT and other ultra low power applications. However, energy efficient circuits show a lesser immunity against soft error, because of the smaller device node capacitances in nanoscale technologies and near-threshold voltage operation. Due to these reasons, the tolerance of the sequential circuits to SEUs is an important consideration in nanoscale near threshold CMOS design. This paper presents an energy efficient SEU tolerant latch. The proposed latch improves the SEU tolerance by using a clocked Muller- C and memory elements based restorer circuit. The parasitic extracted simulations using STMicroelectronics 65 nm CMOS technology show that by employing the proposed latch, an average improvement of ∼40% in energy delay product (EDP), is obtained over the recently reported latch. Moreover, the proposed latch is also validated in a TCAD calibrated PTM 32 nm framework and PTM 22 nm CMOS technology nodes. In 32 nm and 22 nm technologies, the proposed latch improves the EDP ∼12% and 59% over existing latches respectively.     

在ASIC设计中的功耗分析与优化设计

分析了 ＣＭＯＳ数字专用集成电路功耗的来源,给出了半定制数字专用集成电路功耗的计算方法以及功耗优化设计的方法。     

真实FPGA器件下单粒子软错误评估工具设计

FPGA器件在航天领域应用广泛,然而在空间环境下,基于SRAM工艺的FPGA器件极易受到单粒子翻转(Single Event Upsets,SEU)影响而导致电路发生软错误。针对具有代表性的Xilinx Virtex系列器件进行了SEU评估方法的研究,设计并开发了一款面向Virtex器件的SEU效应评估工具,并与FPGA标准设计流程进行了有效融合。实验结果表明,提出的评估方法和工具对Virtex器件的SEU效应可以进行准确的评估,从而为FPGA结构设计和应用开发提供先于硬件实现的软件验证环境,对高可靠性FPGA芯片的研究、开发和设计都具有重要意义。     

Fault-tolerant TMR and DMR circuits with latchup protection switches

The paper presents CMOS ASICs which can tolerate the single event upsets (SEUs), the single event transients (SET), and the single event latchup (SEL). Triple and double modular redundant (TMR and DMR) circuits in combination with SEL protection switches (SPS) make the base of the proposed approach. The SPS had been designed, characterized, and verified before it became a standard library cell. A few additional steps during logic synthesis and layout generation have been introduced in order to implement the redundant net-lists and power domains as well as to place the latchup protection switches. The approach and accompanying techniques have been verified on the example of a shift-register and a middleware switch processor.     

ASIC设计中测试矢量产生与验证

介绍了ASIC设计过程中测试矢量的产生与验证步骤，包括激励编写规划、波形检查、测试矢量的获得以及测试矢量的验证。