by Lo Wing-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves vii-ix). / ABSTRACT --- p.i / LIST OF TABLES --- p.iv / LIST OF FIGURES --- p.v / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Traditional Design Prototyping --- p.1 / Chapter 1.2 --- In-Circuit Rapid Prototyping System --- p.2 / Chapter 1.3 --- A Summary of Prototyping Systems Available --- p.5 / Chapter 1.4 --- Universal Prototyping Board (UPB) --- p.6 / Chapter 2. --- HARDWARE DESIGNS --- p.9 / Chapter 2.1 --- Bus Interconnection --- p.9 / Chapter 2.1.1 --- Fixed buses --- p.9 / Chapter 2.1.2 --- Programmable buses --- p.12 / Chapter 2.2 --- Architectural Features --- p.15 / Chapter 2.2.1 --- Field programmable gate array --- p.15 / Chapter 2.2.2 --- Microprocessor --- p.15 / Chapter 2.2.3 --- Memory --- p.16 / Chapter 2.2.4 --- Buffers --- p.18 / Chapter 3. --- SOFTWARE TOOLS --- p.20 / Chapter 3.1 --- Critical Path Analysis --- p.20 / Chapter 3.1.1 --- Algorithm of critical path analysis --- p.21 / Chapter 3.1.2 --- Computation time --- p.21 / Chapter 3.2 --- Circuit Partitioning --- p.23 / Chapter 3.2.1 --- Partitioning algorithm --- p.24 / Chapter 3.2.2 --- Effects of partitioning --- p.36 / Chapter 3.2.3 --- Partitioning parameters --- p.38 / Chapter 3.2.4 --- Pseudo-code of partitioner --- p.39 / Chapter 3.3 --- IO Assignments --- p.40 / Chapter 3.3.1 --- Connect 4 FPGAs --- p.40 / Chapter 3.3.2 --- Connect 3 FPGAs --- p.42 / Chapter 3.3.3 --- Connect 2 FPGAs --- p.44 / Chapter 3.3.4 --- System IO (Connect 1 FPGA) --- p.47 / Chapter 3.4 --- Other Tools --- p.48 / Chapter 4. --- STRUCTURE ANALYSIS --- p.49 / Chapter 5. --- RESULTS --- p.52 / Chapter 6. --- FUTURE DIRECTION --- p.73 / Chapter 6.1 --- Other Possible Configurations --- p.73 / Chapter 6.2 --- Programmable Interconnection --- p.73 / Chapter 6.3 --- Expandability of UPB --- p.74 / Chapter 7. --- CONCLUSION --- p.75 / BIBLIOGRAPHY --- p.vii / APPENDICES --- p.x

"It is widely recognized that security issues will play a crucial role in the majority of future computer and communication systems. A central tool for achieving system security are cryptographic algorithms. For performance as well as for physical security reasons, it is often advantageous to realize cryptographic algorithms in hardware. In order to overcome the well-known drawback of reduced flexibility that is associated with traditional ASIC solutions, this contribution proposes arithmetic architectures which are optimized for modern field programmable gate arrays (FPGAs). The proposed architectures perform modular exponentiation with very long integers. This operation is at the heart of many practical public-key algorithms such as RSA and discrete logarithm schemes. We combine two versions of Montgomery modular multiplication algorithm with new systolic array designs which are well suited for FPGA realizations. The first one is based on a radix of two and is capable of processing a variable number of bits per array cell leading to a low cost design. The second design uses a radix of sixteen, resulting in a speed-up of a factor three at the cost of more used resources. The designs are flexible, allowing any choice of operand and modulus. Unlike previous approaches, we systematically implement and compare several versions of our new architecture for different bit lengths. We provide absolute area and timing measures for each architecture on Xilinx XC4000 series FPGAs. As a first practical result we show that it is possible to implement modular exponentiation at secure bit lengths on a single commercially available FPGA. Secondly we present faster processing times than previously reported. The Diffie-Hellman key exchange scheme with a modulus of 1024 bits and an exponent of 160 bits is computed in 1.9 ms. Our fastest design computes a 1024 bit RSA decryption in 3.1 ms when the Chinese remainder theorem is applied. These times are more than ten times faster than any reported software implementation. They also outperform most of the hardware-implementations presented in technical literature."

"This thesis describes a co-processor system that has been designed to accelerate computations associated with Singular Value Array Reconciliation Tomography (SART), a method for locating a wide-band RF source which may be positioned within an indoor environment, where RF propagation characteristics make source localization very challenging. The co-processor system is based on field programmable gate array (FPGA) technology, which offers a low-cost alternative to customized integrated circuits, while still providing the high performance, low power, and small size associated with a custom integrated solution. The system has been developed in VHDL, and implemented on a Virtex-4 SX55 FPGA development platform. The system is easy to use, and may be accessed through a C program or MATLAB script. Compared to a Pentium 4 CPU running at 3 GHz, use of the co-processor system provides a speed-up of about 6 times for the current signal matrix size of 128-by-16. Greater speed-ups may be obtained by using multiple devices in parallel. The system is capable of computing the SART metric to an accuracy of about -145 dB with respect to its true value. This level of accuracy, which is shown to be better than that obtained using single precision floating point arithmetic, allows even relatively weak signals to make a meaningful contribution to the final SART solution."

The increasing commoditization of computers in modern society has exceeded the pace of associated developments in reliability. Although theoretical computer science has advanced greatly in the last thirty years, many of the best techniques have yet to find their way into embedded computers, and their failure can have a great potential for disrupting society. This dissertation presents some approaches to improve computer reliability using software and hardware techniques, and makes the following claims for novelty: innovative development of a toolchain and libraries to support extraction from dependent type checking in a theorem prover; conceptual design and deployment in reconfigurable hardware; an extension of static type-safety to hardware description language and FPGA level; elimination of legacy C code from the target and toolchain; a novel hardware error detection scheme is described and compared with conventional triple modular redundancy. The elimination of any user control of memory management promotes robustness against buffer overruns, and consequently prevents vulnerability to common Trojan techniques. The methodology identifies type punning as a key weakness of commonly encountered embedded languages such as C, in particular the extreme difficulty of determining if an array access is in bounds, or if dynamic memory has been properly allocated and released. A method of eliminating dependence on type-unsafe libraries is presented, in conjunction with code that has optionally been proved correct according to user-defined criteria. An appropriately defined subset of OCaml is chosen with support for the Coq theorem prover in mind, and then evaluated with a custom backend that supports behavioural Verilog, as well as a fixed execution unit and associated control store. Results are presented for this alternative platform for reliable embedded systems development that may be used in future industrial flows. To provide assurance of correct operation, the proven software needs to be executed in an environment where errors are checked and corrected in conjunction with appropriate exception processing in the event of an uncorrectable error. Therefore, the present author’s previously published error detection scheme based on dual-rail logic and self-checking checkers is further developed and compared with traditional N-modular redundancy.

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores - Major Telecomunicações. Faculdade de Engenharia. Universidade do Porto. 2013

Most existing computers today are built upon a subset of the arithmetic system which is based upon the foundation of set theory. All formal systems can be expressed in terms of arithmetic and logic on current arithmetic computers through an appropriate model, then work with the model using software manipulation. However, severe speed degradation is the price one must pay for using a software-based approach, making several high-level formal systems impractical. To improve the speed at which computers can implement these high-level systems, one must either design special hardware, implementing specific operations much like math and image processing coprocessors, or execute operations upon multiple processors in a parallel fashion. Due to the increase in developing applications for the manipulation of logic functions, an interest in the logic machine has arisen. Many applications such as logic optimization, simulation, pattern recognition and image processing can be better implemented with a logic machine. This thesis proposes the design, hardware realization, and testing of the iterative logic unit (ILU) of the Cube Calculus Machine II (CCM2). The CCM2 is a general purpose computer with an architecture that emphasizes a data path designed to execute operations of cube calculus, a popular algebraic model used in the minimization of Boolean functions. The ILU is an iterative logic array of cells (ITs) using internal distributed control, enabling the execution of basic cube operations, while the Control Unit (CU) handles global signals from the host computer. The ILU of the CCM2 has been realized in hardware using Xilinx Logic Cell Arrays (LCAs). FPGAs offer the logic density and versatility of gate arrays, with the off-the shelf availability and time-to-market advantages of standard user-programmable devices. These devices can be reconfigured, allowing multiple revisions and future design generations to accommodate the same device, thus saving design and production costs, an ideal solution to the resource and financial problems plaguing the University environment.

The new family of Field Programmable Gate Arrays, CLI 6000 from Concurrent Logic Inc realizes truly Cellular Logic. It has been mainly designed for the realization of data path architectures. However, the realizable logic functions provided by its macrocells and their limited connectivity call also for new general-purpose logic synthesis methods. The basic cell of CLi 6000 can be programmed to realize a two-input multiplexer ( A*B + C*B ), an AND/EXOR cell ( A*B Ea C ), or the basic 2-input AND, OR and EXOR gate. This suggests to using these cells for tree-like expansions. These "cellular logic" devices require regular connection patterns in the netlists resulting from logic synthesis. This thesis presents a synthesis tree searching program PROMPT, which generates AND/EXOR tree circuits from given Boolean functions. Such circuits have the property that the gate structures are AND/EXOR ( A *B EB C ), AND and EXOR which could be realized by the CLI6000 cells. Also, the connection. way in the circuit is that usually the output of one level gate is the input of the next level gate of the tree. This matches ideally to the architecture of the CLI6000 bussing network where the macrocells have only connections to their neighboring cells. PROMPT is based on the Davio expansions ( an equivalent of the Shannon expansions for the EXOR gates ) as its Boolean decomposition methods. The program includes three versions: exact version, heuristic version and fixed-variable version. The exact version of PROMPT generates the Permuted Reed-Muller Tree circuit which has the minimum number of gates. Such tree circuit is obtained by searching through all possible combinations of the expansion variable orders to get the one which needs the least number of gates. The heuristic version of PROMPT is designed to decrease the time complexity of the search algorithm when dealing with logic functions having many input variables. It generates a Permuted Reed-Muller Tree which may not have the minimum number of gates. However, the tree searching time in this version decreases tremendously compared to the time necessary in the exact version. The fix-variable version is developed to generate Reed-Muller Tree circuits. Such circuits will have the same expansion variables at the same tree level, so they can be easier routed after the placement to the CLI6000 chips. In short, the program PROMPT generates the PRM and RM tree circuits which are particularly well matched to both the realization of logic cell and connection structure of the CLI6000 device. Thus, the PRM and RM circuits can be easily placed and routed on the CLI6000 FPGAs.

Unmanned vehicles, both ground and aerial, have become prevalent in recent years. The research community has different needs than the industrial community when designing a finalized unmanned system since the vehicle, the sensors and the control design are dynamic and change frequently as new ideas are developed and implemented. Current autopilot hardware, which is available as on-the-market products and proposed in research, is sufficient for unmanned systems design. However, this equipment falls short of being able to accommodate the needs of those in the research community who must be able to quickly implement new ideas on a flexible platform. The contribution of this research is the realization of a hardware platform, which provides for rapid implementation of newly developed theory. Rapid implementation is gained by providing for software development from within the Simulink environment and utilizing previously unrealized flexibility in sensor selection. In addition to the development of the hardware platform, research was performed within Simulink's System Generator environment in order to complement the hardware. The software produced consists of a user template that integrates to the selected hardware. The template creates a user friendly environment, which provides the end user the capability to develop software algorithms from within the Simulink environment. This capability facilitates the final step of full hardware implementation. The major novelty of the research was the overall FPGA based autopilot design. The approach provided flexibility, functionality and generality. The approach is also suitable for and applicable to the design of multiple platforms. This research yielded a first time approach to the development of an unmanned systems autopilot platform by utilizing: -Development of programmable voltage level digital Input/Output (I/O), ports, -Utilization of Field Programmable Analog Arrays (FPAA), -Hardware capabilities to allow for integration with full computer systems, -A full Field Programmable Gate Array (FPGA), implementation, -Full integration of the hardware within Simulink's System Generator Toolbox

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

In modern point to point microwave radio systems used to backhaul cellular voice and data traffic, quadrature amplitude modulation (QAM) is the norm. These systems require a highly linear power amplifier which is expensive and has relatively low power efficiency. Recently, continuous phase modulation (CPM) has been deployed in this market. The CPM transmitted waveform has a constant envelope and so a non-linear RF power amplifier can be used. This significantly reduces cost and improves power efficiency. Two important disadvantages of CPM are receiver complexity and inferior spectral efficiency compared to QAM. This thesis demonstrates a 50% spectral efficiency improvement over an existing CPM configuration without loss of detection efficiency. This is achieved by moving to coherent demodulation and extending the duration of the CPM phase pulse to 3 symbol periods. This new CPM configuration of h=1/4, M=4, L=3, is evaluated against ETSI requirements for a 28 MHz channel carrying 24 E1 circuits. Simulation of the receiver floating point model demonstrates all requirements are met. The detection efficiency requirement is exceeded by 4.7 dB. Carrier recovery, phase and timing synchronisation are assumed to be ideal. The 50% increased symbol rate, coherent reception and a longer smoother phase pulse, conspire to increase receiver complexity substantially. The Viterbi algorithm is used to perform maximum-likelihood detection resulting in a 128 state trellis. This application has a stringent cost requirement that limits the implementation target to a Field Programmable Gate Array (FPGA) costing less than US$30. To demonstrate this demanding cost target is met, the two most computationally expensive receiver functions, the branch metric unit and path metric processing unit, are implemented in VHDL and targeted to a Xilinx Spartan 3A-DSP 1800 FPGA. The implementation uses 67% of the available logic resources, thus meeting the cost requirement. The branch metric unit is implemented using a distributed arithmetic technique that performs the equivalent of 27.6 giga-multiplies/s, consuming only 23% of the available FPGA logic cells. This is very efficient compared to a conventional approach using all the FPGA’s embedded multipliers which combined can only achieve 21 giga-multiplies/s. The Viterbi path metric processing unit is implemented using a more conventional state-parallel architecture. To reduce state metric routing complexity, states are grouped into radix-4 units comprising dual add-compare-select (ACS) units. By utilising a spare cycle in the deep ACS pipeline, each ACS unit processes two output state metrics, thus halving the number of ACS units required. This implementation uses 44% of the available FPGA resources and meets timing at 204.5 MHz, exceeding the throughput requirement of 54 Mbit/s.