Dynamic partial reconfiguration of FPGAs allows systems to autonomously alter sections of their design during runtime based on the state of the system. This functionality provides size, weight, and power benefits that are useful in extreme environments such as space. Therefore, NASA has requested research into the feasibility of using a commercial off-the-shelf software flow to convert a static HDL design to support partial reconfiguration. This project presents an analysis of this conversion process using the Xilinx Partial Reconfiguration Flow to convert the static design for the ITU G.729 Voice Decoder. This paper explores the design modifications that must be made to allow for partial reconfiguration. Furthermore, an in-depth description of how to set up the hardware platform to support the HDL application is provided. Finally, timing and size data are presented and analyzed to empirically show the benefits and limitations of using dynamic partial reconfiguration.

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FPGA design implementation and debug tools have not kept pace with the advances in FPGA device density. The emphasis on area optimization and circuit speed has resulted in longer runtimes of the implementation tools. We address the implementation problem using a divide-and-conquer approach in which some device area and circuit speed is sacrificed for improved implementation turnaround time. The PATIS floorplanner enables dynamic modular design that accelerates implementation for incremental changes to a design. While the existing implementation flows facilitate timing closure late in the design cycle by reusing the layout of unmodified blocks, dynamic modular design accelerates implementation by achieving timing closure for each block independently. A complete re-implementation is still rapid as the design blocks can be processed by independent and concurrent invocations of the standard tools. PATIS creates the floorplan for implementing modules in the design. Bus macros serve as module interfaces and enable independent implementation of the modules. The dynamic modular design flow achieves around 10x speedup over the standard design flow for our benchmark designs. / Master of Science

FPGA implementation tool speed has not kept pace with the increase in design size and FPGA density. It is difficult to parallelize place-and-route algorithms without sacrificing determinism or quality of results. We address the implementation problem using a divide-and-conquer approach. The PATIS automatic floorplanner enables dynamic modular design, which sacrifices some design speed and area optimization for faster implementation of layout changes, including addition of debug logic. Automatic generation of a timing-driven floorplan for a partially reconfigurable design aims to remove the need for implementation iterations to meet all constraints. Floorplan speculation may anticipate small changes to a design. Although PATIS supports incremental design, complete re-implementation is still rapid because the partial bitstream for each block is generated by independent concurrent invocations of the standard Xilinx tools. / Master of Science

FPGA implementation tool turnaround time has unfortunately not kept pace with FPGA density advances. It is difficult to parallelize place-and-route algorithms without sacrificing determinism or quality of results. We approach the problem in a different way for development environments in which some circuit speed and area optimization may be sacrificed for improved implementation and debug turnaround. The PATIS floorplanner enables dynamic modular design, which accelerates non-local changes to the physical layout arising from design exploration and the addition of debug circuitry. We focus in this work on incremental and speculative floorplanning in PATIS, to accommodate minor design changes and to proactively generate possible floorplan variants. Current floorplan topology is preserved to minimize ripple effects and maintain reasonable module aspect ratios. The design modules are run-time reconfigurable to enable concurrent module implementation by independent invocations of the standard FPGA tools running on separate cores or hosts. / Master of Science

Made available in DSpace on 2015-05-08T14:57:17Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3191819 bytes, checksum: 142a338f10b5b1c73f589237be4728c2 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work aims to carry out an analysis of the main existing testing strategies for FPGA, and propose a new strategy applied to the interconnection network of the Xilinx Spartan 3E FPGA based on linear feedback shift register synthesized by Berlekamp Massey Algorithm that can accurately localize the failure. For this, we used softwares from Xilinx manufacturer (specifically, XDL and FPGA_editor) to determine the FPGA based configuration and than create a new proposal and evaluate their employability. As a result of the proposed strategy, it was possible to route 7 WUTs (Wires Under Test) of total of 8 for the FPGA under investigation. Thus, it was necessary 24 test configurations to test and locate the failure on all hexlines and doublelines. The results show that this strategy is able to test 7 WUTs at a time and needs 24 test configurations to test and diagnose precisely the failure location. / Este trabalho objetiva realizar uma análise das principais estratégias de teste já existentes para FPGA, e propor uma nova estratégia aplicada à rede de interconexão do FPGA Xilinx Spartan 3E baseada em registradores de deslocamento com realimentação linear sintetizável pelo Algoritmo de Berlekamp-Massey e que possa diagnósticar com precisão o local da falha. Para isso, foram utilizados softwares da fabricante de FPGAs Xilinx (especificamente, XDL e FPGA_editor) para determinar precisamente a configuração do FPGA e, assim, criar uma nova proposta e avaliar sua empregabilidade. Como resultado, a partir da estratégia adotada foi possível rotear 7 WUTs (Wires Under Test) em um total de 8 para o FPGA em questão. Sendo assim, foram necessárias 24 configurações de teste para testar e diagnósticar todas as linhas do tipo HexLine e DoubleLine. Os resultados obtidos mostram que a estratégia proposta é capaz de testar 7 WUTs por vez e necessita de 24 configurações para testar e diagnósticar precisamente o local da falha na rede de interconexão.

FPGAs have become quite popular for implementing digital circuits and systems because of reduced costs and fast design cycles. This has led to increased complexity of FPGAs, and with technology scaling, many new challenges have come up for the FPGA industry, leakage power being one of the key challenges. The current generation FPGAs are being implemented in 90nm technology, therefore, managing leakage power in deep-submicron FPGAs has become critical for the FPGA industry to remain competitive in the semiconductor market and to enter the mobile applications domain. <br /><br /> In this work an analytical state dependent leakage power model for FPGAs is developed, followed by dual-Vt based designs of the FPGA architecture for reducing leakage power. <br /><br /> The leakage power model computes subthreshold and gate leakage in FPGAs, since these are the two dominant components of total leakage power in the scaled nanometer technologies. The leakage power model takes into account the dependency of gate and subthreshold leakage on the state of the circuit inputs. The leakage power model has two main components, one which computes the probability of a state for a particular FPGA circuit element, and the other which computes the leakage of the FPGA circuit element for a given input using analytical equations. This FPGA power model is particularly important for rapidly analyzing various FPGA architectures across different technology nodes. <br /><br /> Dual-Vt based designs of the FPGA architecture are proposed, developed, and evaluated, for reducing the leakage power using a CAD framework. The logic and the routing resources of the FPGA are considered for dual-Vt assignment. The number of the logic elements that can be assigned high-Vt in the <em>ideal</em> case by using a dual-Vt assignment algorithm in the CAD framework is estimated. Based upon this estimate two kinds of architectures are developed and evaluated, homogeneous and heterogeneous architectures. Results indicate that leakage power savings of up to 50% can be obtained from these architectures. The analytical state dependent leakage power model developed has been used for estimating the leakage power savings from the dual-Vt FPGA architectures. The CAD framework that has been developed can also be used for developing and evaluating different dual-Vt FPGA architectures, other than the ones proposed in this work.

The scaling of the CMOS technology has precipitated an exponential increase in both subthreshold and gate leakage currents in modern VLSI designs. Consequently, the contribution of leakage power to the total chip power dissipation for CMOS designs is increasing rapidly, which is estimated to be 40% for the current technology generations and is expected to exceed 50% by the 65nm CMOS technology. In FPGAs, the power dissipation problem is further aggravated when compared to ASIC designs because FPGA use more transistors per logic function when compared to ASIC designs. Consequently, solving the leakage power problem is pivotal to devising power-aware FPGAs in the nanometer regime. This thesis focuses on devising both architectural and CAD techniques for leakage mitigation in FPGAs. Several CAD and architectural modifications are proposed to reduce the impact of leakage power dissipation on modern FPGAs. Firstly, multi-threshold CMOS (MTCMOS) techniques are introduced to FPGAs to permanently turn OFF the unused resources of the FPGA, FPGAs are characterized with low utilization percentages that can reach 60%. Moreover, such architecture enables the dynamic shutting down of the FPGA idle parts, thus reducing the standby leakage significantly. Employing the MTCMOS technique in FPGAs requires several changes to the FPGA architecture, including the placement and routing of the sleep signals and the MTCMOS granularity. On the CAD level, the packing and placement stages are modified to allow the possibility of dynamically turning OFF the idle parts of the FPGA. A new activity generation algorithm is proposed and implemented that aims to identify the logic blocks in a design that exhibit similar idleness periods. Several criteria for the activity generation algorithm are used, including connectivity and logic function. Several versions of the activity generation algorithm are implemented to trade power savings with runtime. A newly developed packing algorithm uses the resulting activities to minimize leakage power dissipation by packing the logic blocks with similar or close activities together. By proposing an FPGA architecture that supports MTCMOS and developing a CAD tool that supports the new architecture, an average power savings of 30% is achieved for a 90nm CMOS process while incurring a speed penalty of less than 5%. This technique is further extended to provide a timing-sensitive version of the CAD flow to vary the speed penalty according to the criticality of each logic block. Secondly, a new technique for leakage power reduction in FPGAs based on the use of input dependency is developed. Both subthreshold and gate leakage power are heavily dependent on the input state. In FPGAs, the effect of input dependency is exacerbated due to the use of pass-transistor multiplexer logic, which can exhibit up to 50% variation in leakage power due to the input states. In this thesis, a new algorithm is proposed that uses bit permutation to reduce subthreshold and gate leakage power dissipation in FPGAs. The bit permutation algorithm provides an average leakage power reduction of 40% while having less than 2% impact on the performance and no penalty on the design area. Thirdly, an accurate probabilistic power model for FPGAs is developed to quantify the savings from the proposed leakage power reduction techniques. The proposed power model accounts for dynamic, short circuit, and leakage power (including both subthreshold and gate leakage power) dissipation in FPGAs. Moreover, the power model accounts for power due to glitches, which accounts for almost 20% of the dynamic power dissipation in FPGAs. The use of probabilities in the power model makes it more computationally efficient than the other FPGA power models in the literature that rely on long input sequence simulations. One of the main advantages of the proposed power model is the incorporation of spatial correlation while estimating the signal probability. Other probabilistic FPGA power models assume spatial independence among the design signals, thus overestimating the power calculations. In the proposed model, a probabilistic model is proposed for spatial correlations among the design signals. Moreover, a different variation is proposed that manages to capture most of the spatial correlations with minimum impact on runtime. Furthermore, the proposed power model accounts for the input dependency of subthreshold and gate leakage power dissipation. By comparing the proposed power model to HSpice simulation, the estimated power is within 8% and is closer to HSpice simulations than other probabilistic FPGA power models by an average of 20%.

FPGAs have become quite popular for implementing digital circuits and systems because of reduced costs and fast design cycles. This has led to increased complexity of FPGAs, and with technology scaling, many new challenges have come up for the FPGA industry, leakage power being one of the key challenges. The current generation FPGAs are being implemented in 90nm technology, therefore, managing leakage power in deep-submicron FPGAs has become critical for the FPGA industry to remain competitive in the semiconductor market and to enter the mobile applications domain. <br /><br /> In this work an analytical state dependent leakage power model for FPGAs is developed, followed by dual-Vt based designs of the FPGA architecture for reducing leakage power. <br /><br /> The leakage power model computes subthreshold and gate leakage in FPGAs, since these are the two dominant components of total leakage power in the scaled nanometer technologies. The leakage power model takes into account the dependency of gate and subthreshold leakage on the state of the circuit inputs. The leakage power model has two main components, one which computes the probability of a state for a particular FPGA circuit element, and the other which computes the leakage of the FPGA circuit element for a given input using analytical equations. This FPGA power model is particularly important for rapidly analyzing various FPGA architectures across different technology nodes. <br /><br /> Dual-Vt based designs of the FPGA architecture are proposed, developed, and evaluated, for reducing the leakage power using a CAD framework. The logic and the routing resources of the FPGA are considered for dual-Vt assignment. The number of the logic elements that can be assigned high-Vt in the <em>ideal</em> case by using a dual-Vt assignment algorithm in the CAD framework is estimated. Based upon this estimate two kinds of architectures are developed and evaluated, homogeneous and heterogeneous architectures. Results indicate that leakage power savings of up to 50% can be obtained from these architectures. The analytical state dependent leakage power model developed has been used for estimating the leakage power savings from the dual-Vt FPGA architectures. The CAD framework that has been developed can also be used for developing and evaluating different dual-Vt FPGA architectures, other than the ones proposed in this work.

The scaling of the CMOS technology has precipitated an exponential increase in both subthreshold and gate leakage currents in modern VLSI designs. Consequently, the contribution of leakage power to the total chip power dissipation for CMOS designs is increasing rapidly, which is estimated to be 40% for the current technology generations and is expected to exceed 50% by the 65nm CMOS technology. In FPGAs, the power dissipation problem is further aggravated when compared to ASIC designs because FPGA use more transistors per logic function when compared to ASIC designs. Consequently, solving the leakage power problem is pivotal to devising power-aware FPGAs in the nanometer regime. This thesis focuses on devising both architectural and CAD techniques for leakage mitigation in FPGAs. Several CAD and architectural modifications are proposed to reduce the impact of leakage power dissipation on modern FPGAs. Firstly, multi-threshold CMOS (MTCMOS) techniques are introduced to FPGAs to permanently turn OFF the unused resources of the FPGA, FPGAs are characterized with low utilization percentages that can reach 60%. Moreover, such architecture enables the dynamic shutting down of the FPGA idle parts, thus reducing the standby leakage significantly. Employing the MTCMOS technique in FPGAs requires several changes to the FPGA architecture, including the placement and routing of the sleep signals and the MTCMOS granularity. On the CAD level, the packing and placement stages are modified to allow the possibility of dynamically turning OFF the idle parts of the FPGA. A new activity generation algorithm is proposed and implemented that aims to identify the logic blocks in a design that exhibit similar idleness periods. Several criteria for the activity generation algorithm are used, including connectivity and logic function. Several versions of the activity generation algorithm are implemented to trade power savings with runtime. A newly developed packing algorithm uses the resulting activities to minimize leakage power dissipation by packing the logic blocks with similar or close activities together. By proposing an FPGA architecture that supports MTCMOS and developing a CAD tool that supports the new architecture, an average power savings of 30% is achieved for a 90nm CMOS process while incurring a speed penalty of less than 5%. This technique is further extended to provide a timing-sensitive version of the CAD flow to vary the speed penalty according to the criticality of each logic block. Secondly, a new technique for leakage power reduction in FPGAs based on the use of input dependency is developed. Both subthreshold and gate leakage power are heavily dependent on the input state. In FPGAs, the effect of input dependency is exacerbated due to the use of pass-transistor multiplexer logic, which can exhibit up to 50% variation in leakage power due to the input states. In this thesis, a new algorithm is proposed that uses bit permutation to reduce subthreshold and gate leakage power dissipation in FPGAs. The bit permutation algorithm provides an average leakage power reduction of 40% while having less than 2% impact on the performance and no penalty on the design area. Thirdly, an accurate probabilistic power model for FPGAs is developed to quantify the savings from the proposed leakage power reduction techniques. The proposed power model accounts for dynamic, short circuit, and leakage power (including both subthreshold and gate leakage power) dissipation in FPGAs. Moreover, the power model accounts for power due to glitches, which accounts for almost 20% of the dynamic power dissipation in FPGAs. The use of probabilities in the power model makes it more computationally efficient than the other FPGA power models in the literature that rely on long input sequence simulations. One of the main advantages of the proposed power model is the incorporation of spatial correlation while estimating the signal probability. Other probabilistic FPGA power models assume spatial independence among the design signals, thus overestimating the power calculations. In the proposed model, a probabilistic model is proposed for spatial correlations among the design signals. Moreover, a different variation is proposed that manages to capture most of the spatial correlations with minimum impact on runtime. Furthermore, the proposed power model accounts for the input dependency of subthreshold and gate leakage power dissipation. By comparing the proposed power model to HSpice simulation, the estimated power is within 8% and is closer to HSpice simulations than other probabilistic FPGA power models by an average of 20%.