A comparative study of PDSP and FPGA design methodologies for DSP system design A thesis submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the Degree of Master of Science in the Department of Electrical Engineering and Computing Systems of the College of Engineering and Applied Science By Prasad Deodhar Bachelor of Engineering (Computer Engineering) University of Mumbai, India. 2009. Thesis Advisor and Committee Chair: Dr. Carla Purdy ABSTRACT In today’s globally interconnected world, we notice a proliferation of a vast array of electronic devices and systems in our daily life, from industrial automation, military, aerospace, aviation, medicine, consumer electronics to multimedia and entertainment products. The common thread that binds all these devices is that they involve some kind of a human-computer interface that helps the end-user of these devices interact and control the computational system within each device. Such a human –computer interface typically involves some kind of a Digital Signal Processing (DSP) module whose specific task is to accept as input a real-world analog signal, convert it into a digital signal and process the digital signal by means of extracting useful information through transformation, analysis and synthesis to eventually deliver a result that can help in making a decision. Hence DSP serves as the “interface” between the analog domain of real-life signals and the computational world of digital signals. The most widely used hardware platform for DSP system implementation is the Programmable Digital Signal Processor (PDSP). The PDSPs are general purpose microprocessors designed for embedded DSP applications. They contain special architecture and instructions that support execution of computation - intensive DSP algorithms more efficiently. However, rapid advancements in CMOS technology have widened the options available to a hardware engineer for DSP system implementation. The advent of Field Programmable Gate Arrays (FPGAs) with in-built hardware blocks like DSP multiplier cores, hard and soft IP cores and high-level synthesis tools has given the PDSP a strong competitor. A multitude of factors such as development effort, design time, performance in terms of power consumption and speed, time-to-market, prototyping capabilities, design methodologies and architectural flexibility should be considered for DSP system implementation. ii This thesis makes a comparative study of the two hardware platforms – PDSP and FPGA – in terms of design methodologies, architectures, design time and effort and impact of high-level synthesis tools. The objective is to help a DSP hardware engineer make an informed decision on the pros and cons of selecting a particular hardware platform. iii iv ACKNOWLEDGEMENTS First and foremost, I would like to express my gratitude to God, for his blessings and support in every phase of my life. I express my appreciation and thanks to my advisor Dr. Carla Purdy, Associate Professor, University of Cincinnati for her motivation, constant support and guidance that helped me in my research work and writing this thesis. I would also like to sincerely thank Dr. J. Adam Wilson, currently serving as Assistant Professor of Neurology at Cincinnati Children's Hospital and Medical Center, without whose valuable assistance, I would not have been able to work on the hardware and software resources required for the preparation and completion of this study. I express my immense gratitude to Dr. Wilson for his support and guidance. I would like to thank my parents and friends who kept me motivated and without their moral support and motivation this thesis would not have been possible. They have always been a strong pillar of strength, care and inspiration for me. I dedicate this thesis to my sister Swati, who had been the greatest support for me throughout my graduate education. v TABLE OF CONTENTS ABSTRACT ................................................................................................................................. ii ACKNOWLEDGMENTS ......................................................................................................... v LIST OF FIGURES ................................................................................................................. viii LIST OF TABLES ...................................................................................................................... x LIST OF ABBREVIATIONS ................................................................................................... xi 1. INTRODUCTION ................................................................................................................. 1 1.1 Motivation ....................................................................................................................... 1 1.2 Research Overview ......................................................................................................... 2 1.3 Thesis Outline ................................................................................................................. 6 2. BACKGROUND STUDY .................................................................................................. 9 2.1 Introduction ...................................................................................................................... 9 2.2 Impact of VLSI Technology on DSP and Vice-versa .................................................... 11 2.3 Evolution of DSP Hardware ......................................................................................... 13 2.3.1 Programmable Digital Signal Processors (PDSPs) ............................................... 14 2.3.2 Field Programmable Gate Arrays (FPGAs) ......................................................... 18 2.4 VLSI - DSP: An Insight into the Education Perspective .............................................. 22 2.4.1 Present State of VLSI - DSP Education ............................................................... 23 2.4.2 Suggested Improvements in VLSI - DSP Education ........................................... 25 3. PROBLEM STATEMENT ................................................................................................ 27 3.1 Design Methodologies: PDSP and FPGA Design Flows .............................................. 27 3.1.1 DSP System Development Flow Using PDSPs .................................................... 29 vi 3.1.2 DSP System Development Flow Using FPGAs ................................................... 32 3.2 PDSP and FPGA Comparison: Summary of Past Case Studies .................................... 42 3.3 Problem Definition: Scope, Goals & Objectives ........................................................... 47 4. EXPERIMENTS ................................................................................................................ 49 4.1 Introduction .................................................................................................................... 49 4.2 Hardware and Software Overview ................................................................................. 50 4.2.1 Hardware – PDSP: Texas Instruments C5515 Evaluation Board ......................... 50 4.2.2 Software – PDSP: Code Composer Studio IDE ................................................... 54 4.2.3 Hardware – FPGA Altera DE1 Development Board ............................................ 57 4.2.4 Software – FPGA .................................................................................................. 59 4.3 Experiments ................................................................................................................... 65 4.4 Procedure for Implementation ...................................................................................... 69 4.5 Observations and Results .............................................................................................. 71 4.6 Comparison of the Results ............................................................................................. 82 5. CONCLUSIONS AND FUTURE WORK ........................................................................ 88 5.1 Introduction .................................................................................................................... 88 5.2 Conclusions: Template for Hardware Platform Selection ............................................. 89 5.3 Future Trends: Co-Processors – A Hybrid Approach .................................................... 93 5.4 Concluding Remarks ...................................................................................................... 99 REFERENCES ...................................................................................................................... 101 vii LIST OF FIGURES Figure 1: Evolution of DSP Hardware ........................................................................................ 14 Figure 2: PDSP Design Flow [19] ............................................................................................. 30 Figure 3: FPGA Based DSP design approaches ........................................................................ 33 Figure 4: Model Based Design Framework Using Simulink [6] ................................................ 37 Figure 5: FPGA Verification [6] ................................................................................................. 37 Figure 6: Model Based Design: Complete Design Flow [6]......................................................