RecoNoC: a reconfigurable network-on-chip

This article presents the design of RecoNoC: a compact, highly flexible FPGA-based network-on-chip (NoC), that can be easily adapted for various experiments. In this work, we enhanced this NoC with dynamically reconfigurable shortcuts. These can be used to alter the NoC's topology to adapt to the system's communication needs. The design has been implemented and tested on a Xilinx Virtex-2 Pro FPGA, using the TMAP dynamic datafolding toolflow to automatically generate the reconfigurable hardware and the software reconfiguration procedures. The results show that, using dynamic datafolding, the overhead of introducing this shortcut mechanism is limited

Microprocessor fault-tolerance via on-the-fly partial reconfiguration

This paper presents a novel approach to exploit FPGA dynamic partial reconfiguration to improve the fault tolerance of complex microprocessor-based systems, with no need to statically reserve area to host redundant components. The proposed method not only improves the survivability of the system by allowing the online replacement of defective key parts of the processor, but also provides performance graceful degradation by executing in software the tasks that were executed in hardware before a fault and the subsequent reconfiguration happened. The advantage of the proposed approach is that thanks to a hardware hypervisor, the CPU is totally unaware of the reconfiguration happening in real-time, and there's no dependency on the CPU to perform it. As proof of concept a design using this idea has been developed, using the LEON3 open-source processor, synthesized on a Virtex 4 FPG

New Design Techniques for Dynamic Reconfigurable Architectures

L'abstract è presente nell'allegato / the abstract is in the attachmen

Design methodology for runtime reconfigurable FPGA: From high level specification down to implementation

In this paper we present an automatic design generation methodology for heterogeneous architectures composed of processors, DSPs and FPGAs. This methodology is based on an Adequation Algorithm Architecture where application is represented by a control data flow graph and architecture by an architecture graph. We focus on how to take into account specificities of partially reconfigurable components during the adequation process and for the design generation. We present a method which generates automatically the design for both fixed and partially reconfigurable parts of a FPGA. This method uses prefetching technic to minimize reconfiguration latency of runtime reconfiguration and buffer merging to minimize memory requirements of the generated design

Fault tolerance in WBAN applications

One of the most promising applications of IoT is Wireless Body Area Net-works (WBANs) in medical applications. They allow physiological signals monitoring of patients without the presence of nearby medical personnel. Furthermore, WBANs enable feedback action to be taken either periodically or event-based following the Networked Control Systems (NCSs) techniques. This thesis first presents the architecture of a fault tolerant WBAN. Sensors data are sent over two redundant paths to be processed, analyzed and monitored. The two main communication protocols utilized in this system are Low power Wi-Fi (IEEE 802.11n) and Long Term Evolution (LTE). Riverbed Modeler is used to study the system’s behavior. Simulation results are collected with 95% confidence analysis on 33 runs on different initial seeds. It is proven that the system is fully operational. It is then shown that the system can withstand interference and system’s performance is quantified. Results indicate that the system succeeds in meeting all required control criteria in the presence of two different interference models. The second contribution of this thesis is the design of an FPGA-based smart band for health monitoring applications in WBANs. This FPGA-based smart band has a softcore processor and its allocated SRAM block as well as auxiliary modules. A novel scheme for full initial configuration and Dynamic Partial Reconfiguration through the WLAN network is integrated into this design. Fault tolerance techniques are used to mitigate transient faults such as Single Event Upsets (SEUs) and Multiple Event Upsets (MEUs). The system is studied in a normal environment as well as in a harsh environment. System availability is then obtained using Markov Models and a case study is presented

A configurable decoder for pin-limited applications

Pin limitation is the restriction imposed on an IC chip by the unavailability of a sufficient number of I/O pins. This impacts the design and performance of the chip, as the amount of information that can be passed through the boundary of the chip becomes limited. One area that would benefit from a reduction of the effect of pin limitation is reconfigurable architectures. In this work, we consider reconfigurable devices called Field Programmable Gate Arrays (FPGAs). Due to pin limitation, current FPGAs use a form of 1-hot decoder to select elements (one frame at a time) during partial reconfiguration. This results in a slow and coarse selection of elements for reconfiguration. We propose a module that performs a focused selection of only those elements that require reconfiguration. This reduces reconfiguration overheads and enables the speeds needed for dynamic reconfiguration. The problem is that of selecting subsets of an n-element set in a fast, focused and inexpensive manner. This thesis proposes such a configurable decoder that bridges the gap between the inexpensive, but inflexible, fixed 1-hot decoder, and the expensive, but flexible, pure LUT-based decoder. Our configurable decoder uses a LUT with a narrow output and a low cost in tandem with a special fixed decoder called a mapping unit that expands the output of the LUT to a desired n-bit output. We demonstrate several implementations of the mapping unit, each with different capabilities and trade-offs. A key result of this work is that for any gate cost G=O(n logk n) (where k is a constant), if a pure LUT-based solution produces λ independent subsets, then our method produces Ω(λ log n / log log n) independent subsets for the same cost. Our decoder also produces many more dependent subsets (that depend on the choice of the Ω( λ log n / log log n) independent subsets). We provide simulation results for the configurable decoder and predict future trends from the simulation data; these confirm the theoretical advantages of the proposed decoder. We illustrate the implementation of important subset classes on our configurable decoder and make key observations on a generalized variant

FPGAs in Industrial Control Applications

The aim of this paper is to review the state-of-the-art of Field Programmable Gate Array (FPGA) technologies and their contribution to industrial control applications. Authors start by addressing various research fields which can exploit the advantages of FPGAs. The features of these devices are then presented, followed by their corresponding design tools. To illustrate the benefits of using FPGAs in the case of complex control applications, a sensorless motor controller has been treated. This controller is based on the Extended Kalman Filter. Its development has been made according to a dedicated design methodology, which is also discussed. The use of FPGAs to implement artificial intelligence-based industrial controllers is then briefly reviewed. The final section presents two short case studies of Neural Network control systems designs targeting FPGAs