Multioperand Redundant Adders on FPGAs

Field-programmable gate arrays (FPGAs) provide a promising technology that can improve performance of many high-performance computing and embedded applications. However, unlike software design tools, the relatively immature state of FPGA tools significantly limits productivity and consequently prevents widespread adoption of the technology. For example, the lengthy design-translate-execute (DTE) process often must be iterated to meet the application requirements. Previous works have enabled model-based, design-space exploration to reduce DTE iterations but are limited by a lack of accurate model-based prediction of key design parameters, the most important of which is clock frequency. In this paper, we present a core-level modeling and design (CMD) methodology that enables modeling of FPGA applications at an abstract level and yet produces accurate predictions of parameters such as clock frequency, resource utilization (i.e., area), and latency. We evaluate CMD’s prediction methods using several high-performance DSP applications on various families of FPGAs and show an average clock-frequency prediction error of 3.6%, with a worst-case error of 20.4%, compared to the best of existing high-level prediction methods, 13.9% average error with 48.2% worst-case error. We also demonstrate how such prediction enables accurate design-space exploration without coding in a hardware-description language (HDL), significantly reducing the total design time.

The advent of space applications with increased computational requirements has led the space industry to consider innovative chips and avionics architectures for high-performance on-board data processing. In a relatively limited market, the European BRAVE family of Field-Programmable Gate Arrays (FPGAs) offers such novel radiation-hardened solutions. Towards verification, the current work devises and applies a methodology to thoroughly assess the BRAVE FPGAs and their SW tools. The paper focuses on NG-Large, i.e., the largest FPGA of the 65nm Radiation-Hardened-By-Design (RHBD) technology of NanoXplore to date. The proposed approach comprises a number of customized steps to systematically evaluate the entire FPGA design flow. Initially, we carefully select and tune a set of high-performance Digital Signal Processing (DSP) & Computer Vision (CV) benchmarks, which were originally developed as Hardware Description Language (HDL) IPs in past projects of the European Space Agency (ESA). Subsequently, we perform exhaustive exploration of the Synthesis, Placement, and Routing stages of the SW tools, as well as testing on actual HW boards. At each step, we generate and analyze a variety of results, while we also compare them to 3rd-party solutions. The results show that NG-Large provides sufficient programmability and performance, e.g., classic CV IPs for feature detection on megapixel images can achieve a throughput of 5–10 frames per second, while the on-chip memory utilization is up to 56% better than that of 3rd-party FPGAs. As a highlight, at system-level, we successfully implement and execute an entire HW/SW algorithmic pipeline for Vision-Based Navigation (VBN) involving SpaceWire data transfers with LEON CPU & NG-Large co-processing.

The expanded use of field programmable gate arrays (FPGA) in remote, long life, and system-critical applications requires the development and implementation of effective, efficient FPGA fault-tolerance techniques. FPGA have inherent redundancy and in-the-field reconfiguration capabilities, thus providing alternatives to standard integrated circuit redundancy-based fault-recovery techniques. Runtime reliability can be enhanced by using such unique features. Recovery from permanent logic and interconnect faults without runtime computer-aided design (CAD) support can be efficiently performed with the use of fine-grained and physical design partitioning. Faults are localized to small partitioned blocks that have fixed interfaces to the surrounding portions of the design, and the affected blocks are reconfigured with previously generated, functionally equivalent block instances that do not use the faulty resources. This technique minimizes the post-fault-detection system downtime, while requiring little area overhead. Only the finely located faulty portions of the FPGA are removed from use. In addition, the end user need not have access to CAD tools, making the algorithm completely transparent to system users. This approach has been efficiently implemented on a diverse set of FPGA architectures. The algorithm's flexibility is also apparent from the variable emphases that can be placed on system reliability, area overhead, timing overhead, design effort, and system memory. Given user-defined emphases, the algorithm can be modified to specific application requirements. Experiments using random s-independent and s-correlated fault models reveal that the approach enhances system reliability, while minimizing area and timing overhead.

The paper introduced the principle of DDS technology using of Field Programmable Gate Array (FPGA). It mainly describes the circuit structure and optimization method and designs the VHDL source code adopting on the chip EP1C3T144C8 Cyclone I family FPGA using ALERA Company. It has been greatly applied in electronic design.

This paper presents an I/sub DDQ/-based test strategy for detecting bridging faults in the logic resources of reprogrammable field programmable gate arrays (FPGAs). The proposed approach utilizes the programmability of the configurable logic blocks (CLBs) to achieve 100 percent coverage of I/sub DDQ/ testable bridging faults. We use a hierarchical approach for generating tests and configurations. At the chip level, the CLBs are viewed as a homogeneous two-dimensional array. Two configuration strategies are suggested to simultaneously test each CLB. Within each CLB, we test for external bridging faults between the combinational and sequential logic modules (e.g., flip-flops, multiplexers, lookup tables), Finally, we test for internal bridging faults within each module based on their implementation. Since reconfiguration programming time dominates total test time, even with slow I/sub DDQ/ vectors, we use a bottom-up test generation approach to minimize the number of programming phases first and, then, to minimize the number of test vectors. The Xilinx XC4000 family of SRAM-based FPGAs is used as an example application of the proposed approach. One hundred percent coverage for I/sub DDQ/-testable bridging faults is achieved in five programming phases and 16 I/sub DDQ/ vectors. Since the lookup tables in the CLB can be configured as RAM, the RAM modes are also tested. This requires a further phase, using 48 test vectors and 38 I/sub DDQ/ measurements.

There is still no partial reconfiguration tool support on low-cost Field Programmable Gate Arrays (FPGAs) such as old-fashioned Spartan-3 and state-of-the-art Spartan-6 FPGA families by Xilinx. This forces the designers and engineers, who are using the partial reconfiguration capability of FPGAs, to use expensive families such as Virtex-4, Virtex-5 and Virtex-6 which are officially supported by partial reconfiguration (PR) software. Moreover, Xilinx still does not offer a portable, dedicated self-reconfiguration engine for all of the FPGAs. Self-reconfiguration is achieved with general-purpose processors such as MicroBlaze and PowerPC which are too overqualified for this purpose. In this study, we propose a new self-reconfiguration mechanism for Spartan-6 FPGAs. This mechanism can be used to implement large and complex designs on small FPGAs as chip area can be dramatically reduced by exploiting the dynamic partial reconfiguration feature for on-demand functionality loading and maximal utilization of the hardware. This approach is highly attractive for designing low-cost compute-intensive applications such as high performance image processing systems. For Spartan-6 FPGAs, we have developed hard-macros and exploited the self-reconfiguration engine, compressed Parallel Configuration Access Port (cPCAP) [1], that we designed for Spartan-3. The modified cPCAP core with block RAM controller, bitstream decompressor unit and Internal Configuration Access Port (ICAP) Finite State Machine (FSM) occupies only about 82 of 6,822 slices (1.2% of whole device) on a Spartan-XC6SLX45 FPGA and it achieves the maximum theoretical reconfiguration speed of 200MB/s (ICAP, 16-bit at 100MHz) proposed by Xilinx. We have also implemented a Reconfigurable Processing Element (RPE) whose arithmetic unit can be reconfigured on-the-fly. Multiple RPEs can be utilized to design a General Purpose Image Processing System (GPIPS) that can implement a number of different algorithms during runtime. As an illustrative example, we programmed the GPIPS on Spartan-6 for switching between two applications on-demand such as two-dimensional filtering and block-matching.

The growing complexity of embedded systems makes reconfiguration and embedded OSs (Operating Systems) more and more interesting. FPGAs (Field-Programmable Gate Arrays) are able to perform such a feature with success. With most of the FPGAs, the OS is stored into an external memory (usually Flash) and running on a processor embedded into the FPGA. We consider that FPGA embedded processor is able to process the OS update through, for instance, an insecure network. However, these features may give rise to security flaws affecting the system integrity or freshness. Integrity can be altered by spoofing or modifying data in order to introduce malicious code. In the same way, freshness can be affected by replaying an old configuration in order to downgrade the system. This work proposes a trusted computing mechanism taking into account the whole security chain from bit stream-to-kernel-boot ensuring, both hardware and software, integrity while preventing replay attacks. This paper summarizes the current counter-measures ensuring integrity, confidentiality and freshness of the bit stream. Then we propose a solution to protect OS kernel against malicious modifications thanks to already trusted bit stream power-up. We also evaluate the area and performance overhead of the proposed architecture and its improvement using asymmetric cryptography. Adding security and increasing performances, this solution generates between 0 and 40% of area overhead depending on the re-usability consideration.

This article describes an image processing system based on an intelligent ad-hoc camera, whose two principle elements are a high speed 1.2 megapixel Complementary Metal Oxide Semiconductor (CMOS) sensor and a Field Programmable Gate Array (FPGA). The latter is used to control the various sensor parameter configurations and, where desired, to receive and process the images captured by the CMOS sensor. The flexibility and versatility offered by the new FPGA families makes it possible to incorporate microprocessors into these reconfigurable devices, and these are normally used for highly sequential tasks unsuitable for parallelization in hardware. For the present study, we used a Xilinx XC4VFX12 FPGA, which contains an internal Power PC (PPC) microprocessor. In turn, this contains a standalone system which manages the FPGA image processing hardware and endows the system with multiple software options for processing the images captured by the CMOS sensor. The system also incorporates an Ethernet channel for sending processed and unprocessed images from the FPGA to a remote node. Consequently, it is possible to visualize and configure system operation and captured and/or processed images remotely.

A low power CMOS Static Random Access Memory (SRAM) based Field Programmable Gate Arrays (FPGA) architecture is being presented in this paper. The architecture presented here is based on CMOS logic and CMOS SRAMs that are used for on-chip dynamic reconfiguration. This architecture employs the fast and low-power SRAM blocks that are based on 10T SRAM cells. These blocks are employed in fast access of the configuration bits by using the shadow SRAM technique. The dynamic reconfiguration delay is being hidden behind the computation delay through the use of shadow SRAM cells. The combined effect of both the SRAM memory cells and the shadow SRAM scheme enables to support in reducing the delay and also to achieve reduced power consumption. Experimental results show reduced delay of about 8.035ns and power consumption of about 0.015W for the 10T SRAM memory cell with an overhead in area, relative to 4T and 6T SRAM cells. Also, the experimental results include the values of delay of about 8.979ns and power consumption of about 0.052W, achieved for the LB of FPGA architecture which employs CMOS SRAMs using the 10T SRAM memory cells in it.

Field-programmable gate arrays (FPGAs) are integrated circuits whose logic and their interconnections are configurable. These devices are field-programmable, that is, they can be configured by the hardware designer without any intervention of the manufacturer. Most FPGAs can be reprogrammed as many times as we want with a vast variety of digital circuits. Some recent FPGA families are system-on-chips (SoC) with one or more microprocessor cores, memory, cache, and reconfigurable logic allowing the implementation of complex hardware/software systems in a single programmable device. This article focuses on the architecture of FPGAs, including the so called SoC FPGA. It explains the main blocks of the FPGA, how they have evolved along the last decades and the perspectives of next generation FPGAs. It also describes some applicability areas and how its architecture have evolved to adapt to some of these target markets.

The demand for high-performance computing and rapidly increasing power consumption has increased the necessity for application-specific accelerators. In the datacenter and mobile system, more applications are increasingly relying on accelerators. Field-programmable gate arrays (FPGAs) emerge as a good candidate because they have high programmability and power efficiency. As the number of applications requiring acceleration increases, there is huge demand for FPGAs that support multiple contexts. Previous FPGA designs that support multicontext have various shortcomings such as volatility, poor power efficiency, large performance, area, and reconfiguration overhead. In this article, we propose a spin-transfer torque magnetic RAM (STT-MRAM)-based nonvolatile multicontext FPGA (NVMC-FPGA) that overcomes these shortcomings. We introduce the NVMC-FPGA architecture and operation modes that take advantage of nonvolatility and support multicontext. We also develop the multicontext-aware FPGA computer aided design flow to make the most of the NVMC-FPGA. Compared to the conventional SRAM-based FPGA, when eight identical circuits are mapped, the NVMC-FPGA improves the performance by 15.3% on average and reduces the power consumption by 11.2%–80.7%, depending on the number of simultaneously activated circuits. Moreover, when eight different circuits are mapped, the NVMC-FPGA improves the performance by 58.5% on average and reduces the power consumption by 6.2%–63.3%, depending on the number of simultaneously activated circuits.

Input/output (I/O) port is a group of interfaces that has diverse functional structures of a data processing system use to interconnect with each other. I/O port with handshaking capability is one of the powerful configurations to enable digital communication. The main intention of this project is to design prototype of an input/output port with handshaking capability using Field Programmable Gate Array (FPGA). The main reason of using the FPGA technology is it has unlimited number reprogrammed, cuts developing cost and development time. Xilinx Foundation 2.1i Series software in VHDL description was used as a development tool in this project. The VHDL codes were assimilated into a design and development atmosphere to accomplish many subtasks such as FPGA synthesis, optimization, placement, and routing. The successful design was translated, mapped, routed, and placed onto FPGA Demo Board. XC4010XLPC84 Xilinx FPGA from XC4000XL family was used as a target board. In prototype design, the FPGA pins were connected to a parallel printer port by using a coupled 25-pin DB connector, with a 36-pin Centronics connector cable. The output signals were observed and analyzed by using a logic analyzer.

The offloading and acceleration of database operations on field programmable gate arrays (FPGAs) have been extensively studied for a long time. Architectures of join, a key database operation, have been proposed and optimized on FPGAs. However, these join architectures are either resource-intensive or have low-throughput. In this brief, we focus on the equi-join and propose a resource-efficient join architecture based on a tree model. The architecture needs two phases: the build phase, in which a binary tree is built by using the first database table, and the probe phase, in which the architecture searches the tree to find matching solutions through a second database table. In addition, we propose a parallel implementation for this architecture to improve its performance. The proposed design was implemented on a Xilinx FPGA, and the results were compared with the most recent works on hardware join. The experimental results demonstrate that for a range of parallelism and dataset sizes, our design achieves a data throughput of 8–100 million tuples per second, which is compatible with the bus rate, and performs well in balancing resource utilization and data throughput.

Due to technology advances and complexity of designs, thermal issue is a bottleneck in electronics designs. Various dynamic thermal management techniques have been proposed to address this issue. To effectively apply thermal management techniques, providing an accurate thermal map of chips is highly required. For this goal, a network of temperature sensors ought to be provided. There are various implementations for temperature sensors and network of sensors on Field Programmable Gate Arrays (FPGAs). This work defines and formulates four metrics and criteria, in terms of area, thermal, and power overheads and thermal map accuracy for exploring and evaluating efficiency of different implementations of Ring Oscillator-based Temperature Sensor (ROTS) networks on FPGAs and reports the comparison results for 12 networks with various sensor configurations. According to our metrics and experiments, the sensor that it is composed of NOT gates with open latches and RNS ring counter has lower thermal and power overheads compared to other configurations. Moreover, in this work, a new ROTS is presented that occupies 25% less resources than the most compact temperature sensor. Also, it provides 1.72 times higher sensitivity than the best sensitive ROTS design.

In this paper, we propose a hardware architecture to implement a RGB to HMMD Color space converter. This converter presents a fundamental module for the color structure descriptor (CSD) extraction. The CSD provides a high satisfactory image indexing and retrieval results among all MPEG-7color-based descriptors, but the real time implementation of this descriptor still having problems. We propose a hardware implementation of the RGB to HMMD block using Field Programmable Gate Arrays (FPGAs). The proposed implementation architecture can efficiently operate under real time video processing constraints. We have used a new FPGA family to implement the proposed architecture. Synthesis and simulation results of the developed hardware module are given to demonstrate the effectiveness of the implemented architecture and to show the simulations results for a real input image.