María José Moure

Advanced Features and Industrial Applications of FPGAs—A Review

Field programmable gate arrays (FPGAs) have established themselves as one of the preferred digital implementation platforms in a plethora of current industrial applications, and extensions and improvements are still continuously being included in the devices. This paper reviews recent advancements in FPGA technology, emphasizing the novel features that may significantly contribute to the development of more efficient digital systems for industrial applications. Special attention is paid to the design paradigm shift caused by the availability of increasingly powerful embedded (and soft) processors, which transformed FPGAs from hardware accelerators to very powerful system-on-chip (SoC) platforms. New analog resources, floating-point operators, and hard memory controllers are also described, because of the great advantages they provide to designers. Software tools are being strongly influenced by the design paradigm shift, which requires from them a much better support for software developers. Focusing mainly on this issue, recent advancements in software resources [intellectual property (IP) cores and design tools] are also reviewed. The impact of new FPGA features in industrial applications is analyzed in detail in three main areas, namely digital real-time simulation, advanced control techniques, and electronic instrumentation, with focus on mechatronics, robotics, and power systems design. The way digital systems are being currently designed in these areas is comprehensively reviewed, and a critical analysis of how they could significantly benefit from new FPGA features is presented.

Implementing a Fieldbus Interface Using an FPGA

Fieldbuses are serial communication buses frequently used in industrial applications. There are a lot of different commercial solutions making difficult the compatibility between the equipment of different manufacturers. In this way to change an equipment implies to change the fieldbus too with the consequent economic losses. To avoid this problems this paper proposes the implementation of the fieldbus protocol in a reconfigurable device. Using reconfigurable devices it is possible to modify the protocol of a communication bus without changing its hardware support. Due to the diversity of commercial fieldbuses this work is centered on the implementation of a FPGA based interface for WorldFIP, one of the most popular fieldbuses.

Educational application of virtual instruments based on reconfigurable logic

A number of computer assisted learning (CAL) tools which complement traditional learning methods have been developed due to the decreasing cost and increasing capacity of personal computers. Nevertheless, there are only a few experiences of combining CAL tools with practical experiments. This is the particular case of electronics where practical education is based on traditional independent instruments and CAL tools are use for simulation only. A new approach of CAL tools in electronics is the virtual instrumentation technique. Virtual instruments result from the combination of a general purpose computer with a generic data acquisition system in order to emulate several traditional measurement instruments. Virtual instruments are characterized by their versatility and low cost so they are very suitable for educational applications. Nevertheless, the operation rate of these instruments is limited by the general-purpose orientation of the hardware. In this work, the authors propose a new solution for the implementation of virtual instruments based on reconfigurable data acquisition systems. The whole system is characterized by its versatility because software and hardware modules change dynamically according to the application requirements. By this way, virtual instruments provides a link between CAL tools and the external systems used in practical experiments.

A Reconfigurable Communication Processor Compatible with Different Industrial Fieldbuses

Fieldbuses constitute the lower level of communication networks in a flexible manufacturing system. Nowadays there are a lot of proprietary protocols, thus the interconnection of equipment from different manufacturers has become very problematic. Changing equipment supposes the change of the fieldbus too with the consequent economic losses. This paper proposes the implementation of a communication processor based on a reconfigurable device that makes different fieldbuses compatible. In this way, using the appropriate level and impedance matching circuit, the same hardware can be connected to different fieldbuses. In order to verify this proposal a communication processor based on an FPGA supporting two very important fieldbus standards in the area of industrial control such as WorldFIP and Profibus, has been developed. Design constraints and performance of the implemented processor are analyzed in this paper.

Programmable sensor for on-line checking of signal integrity in FPGA-based systems subject to aging effects

In current nanometer technologies, aging effects (due for instance to Negative Bias Thermal Instability) may appear after relatively short operating times, compared to the expected lifetime of circuits, even for relatively short-cycle consumer electronics. Therefore, there is an increasing need for on-chip aging monitoring. This paper presents a programmable aging sensor that can be embedded in FPGA-based designs, using standard resources available in those devices. The sensing principle is to monitor performance degradation over time. Depending on whether dynamic or static aging effects are dominant, the sensor can operate continuously or be only activated at some time intervals. Given the reduced amount of resources required by the sensor, it can be instantiated not only in the critical paths of a circuit, but also in those that may be identified to be more likely affected by aging affects. Experimental results are presented to demonstrate the performance of the proposed sensor.

Hardware solution of a polyphase filter bank for MP3 audio processing

Audio processing and especially MP3 decoding is usually implemented by software due to the complexity of its hardware alternative. This work proposes a hardware solution to one of the most critical parts of an MP3 decoder, the polyphase filter bank. The aim is to improve its operation rate while saving power. The proposal takes advantage of the DSP-oriented architecture of modern FPGAs. Sequential operations in software can be parallelised in hardware and time critical functions can be accelerated. The Alterapsilas Stratix EP1S10F780C6ES FPGA was used as hardware support. DSP Builder design tools was used together with Matlab and Quartus II in order to simplify the design and simulation tasks. As a result, a synthesis polyphase filter bank, working in real time, was designed and tested.

A FPGA-based frequency measurement system for high-accuracy QCM sensors

This paper proposes the design and implementation of a FPGA-based frequency measurement system for Quartz Crystal Microbalance (QCM) sensors. Using different design techniques a bandwidth of 40 MHz and a resolution of 0,05Hz is achieved. This work is part of a bigger project focused on the development of a standalone QCM system for the analysis and characterization of different paints. Two methods are used to implement the digital counter, the direct frequency measurement and the delay lines. Special attention is paid in the design of the time-base generator. Measurement errors due to the drift of the system oscillator are discussed, and several solutions are proposed taking advantage of the embedded DLL circuits available in the FPGAs. The designed digital counter is implemented and tested using the Xilinxpsilas Spartan XC3S200 FPGA.

A Practical Example to Understand Pipeline A/D Converters Performance Using Software Tools

Pipeline A/D converters (ADC) are widely used when a high frequency analog signal is sampled. Nevertheless the architecture and operation of this kind of ADC is limited to the domain of microelectronics experts due to their integration in complex mixed-signal IC. Therefore two main problems emerge when a deep study and analysis of the pipeline converters are carried out. The first is related to their internal structure and operating mode, for example the synchronization between the different concurrent stages is a topic of special importance. At the same time, pipeline ADC are difficult to simulate with the CAD tools commonly used by designers of electronic circuits. The second inconvenience is derived from the difficulty of obtaining a dynamic characterization of this architecture. This paper proposes a simple methodology facilitating the understanding of this kind of ADC through simulation and testing of a basic pipeline structure including a rule for clocking the parallel stages. As an example, a 5-bit pipeline ADC is designed and simulated using Oread Pspice and signal-to-noise ratio and distortion (SINAD), the total harmonic distortion (THD) and effective number of bits (ENOB) parameters are obtained from Matlab scripts

Interactive Practical Teaching of Digital Circuits Design by Means of Field Programmable Gate Arrays

A computer assisted instruction system is presented here. It is focused on the interactive practical teaching of the digital circuit design based on Field Programmable Gate Arrays (FPGAs). The working methodology comprises the proposal of a problem, the search for a circuital solution and the implementation and verification of the designed circuit. This methodology is intended to develop some skills required by the students for the mastery of new technologies and the acquisition of hands-on experience, so important for their future professional life.

Computer Architecture Lab: A bridge between electronics and computers

This paper presents a Computer Architecture Lab based on a hypothetical pedagogical computer and its corresponding software simulator designed at the University of Vigo. This computer simulator permits to access both the architecture and microarchitecture level of the computer. The paper shows the simulator features at both levels, and introduces the use of embedded core for the learning of SoC (System on a Chip) systems. Therefore students can reinforce the software perspective while they learn the design of complex hardware systems.