White Paper. The advantages of using a combination of DSP s and FPGA s. Version: 1.0. Author: Louis N. Bélanger. Date: May, 2004.

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1 White Paper The advantages of using a combination of DSP s and FPGA s Version: 1.0 Author: Louis N. Bélanger Date: May, 2004 Lyrtech Inc

2 The advantages of using a combination of DSP s and FPGA s DSP and FPGA are complementary solutions that provide best-of-both-world processing approaches for high performance real time signal processing systems, and allow designers to capitalize on two complementary technologies where they are best suited. Programmable DSPs are the classic answer to real time signal processing. They offer high-speed, real-time processing performance, low unit power consumption and affordable unit prices. Software programmability also makes them very flexible. FPGAs are increasingly used in real time signal processing. They offer very high performance (parallel processing), flexibility through programmable hardware and affordable cost for complementary functions. Complementary Solution FPGAs typically complement programmable DSPs in high-performance real-time systems in one or more of the following ways: Performance acceleration in the signal processing System logic muxing and consolidation New peripheral or bus interface implementation Why having an FPGA and DSP mixed development environment DSP and FPGA are two different methods used for signal processing. Both technologies are good depending on the processing requirement. For example, there are many high sampling rate applications that an FPGA does easily, while the DSP, generally speaking, is more oriented toward lower sampling rates. On the other hand, many complex software problems cannot be addressed by a FPGA. In many applications, the IDEAL SYSTEM design is to split work between FPGAs and DSPs. With a strong background in both FPGA and DSP technologies, Lyrtech is a pioneer and the industry leader in developing such platforms. By combining industry-leading DSP and FPGA chips - along with a wide variety of addon, high-speed data acquisition modules - in a single, tightly integrated pipelined architecture, Lyrtech's systems make it possible to simplify designers' tasks. Dataintensive, repetitive signal processing functions (e.g., filters, FFTs, intense memory access, etc.) can thus be implemented in the beginning of the processing pipeline within 2

3 an FPGA while the DSP remains free for Code/Math-intensive signal processing functions, or the intelligent core of the application (e.g., compression, encryption, etc.). The DSP is typically a floating-point device (which can also run in fixed-point, if needed) which can also run 'non-optimized' DSP blocks and/or test functions such as described previously. A very efficient DSP/FPGA interface (which uses F-DMA mechanisms) allows, for example, to transfer high-speed test signals between the DSP and FPGA. Moreover, Lyrtech offer best-of-class support for system-level design tools that allow blockdiagram based design and code generation. If the customer does not wish to use such an approach, it is also possible to program the DSP using a low-level approach. Note also that it is also fully possible to program the FPGA as well using direct VHDL tools. Also, system-level System Generator FPGA designs, which might include Xilinx macros, can then be modified and edited in order to test and develop in-house macros that could be used in an SOC design project Input signal Data-Intensive Signal Processing Code-Intensive Signal Processing The ideal and complentary FPGA-DSP processing chain I don t need the DSP on your board In some cases, customers are looking for FPGA-only development, and feel the DSP on our board is not necessary. We usually answer: not a problem: our board can act as an FPGA-only board. But please read on the following example cases. In a specific case, the customer was working on a communication system for video, audio and data and looking for a tool allowing to develop VHDL code from Matlab/Simulink. Our proposed platform, which included audio, video (Pal/NTSC) and IF (65 MHz) I/O and an FPGA that can be targeted from within System Generator was the SignalWAVe. The customer wished to concentrate on FPGA design, and DSP design was auxiliary. In this context, our platform allows to generate FPGA designs that contains System Generator designed VHDL processing; such designs can be real-time clocked, or non-real time co-verified (under the Host control). The DSP, then, acts more like a realtime monitoring device. It can also run DSP auxiliary processes that can analyze data calculated in the FPGA. 3

4 DSP/FPGA design for specific field of applications The benefits of a DSP/FPGA architecture finds theirs way in a multitude of application fields, from wireless to video processing, and even audio and control systems. 1. Wireless Application: (image DSP-FPGA wireless du SDR bundle) In the wireless application area, our Signal Master platforms combine conventional DSPs and FPGAs with system-level tools to provide one of the most advanced and flexible wireless & SDR (Software-Defined Radio) platform on the market, where the FPGA acts as co-processor to the DSP to provide performance head room. 2. SDR Applications: Our fully programmable SDR solutions are turn-key solutions demonstrating IF (Intermediate Frequency) processing in the FPGA for agile downsampling and frequency translation and base band processing in the DSP - allowing the use of mainstream C-based DSP software all programmed from within the Simulink systemlevel environment in real-time. See our material on a SSB (Single-Side Band) radio entirely programmed in system-level on our DSP/FPGA platforms. This demo was a joint project with The MathWorks. 3. Smart Antenna (or MIMO : Multiple Inputs, Multiple Outputs) Applications: FPGA-processing in array antennas can be used in the context of evaluating DOA (Direction of Arrival) algorithms as well as beam-forming, space-time processing, etc.. DOA algorithms are a basic function of array antennas while allowing estimating the angular direction of the other transmitting system. This value is used by background processes (that can run on the DSP) to perform localization of terminals and beamform the antennas pattern in order to point electronically and have maximum gain in the direction of the other system, which can be mobile. Continual evaluation of the DOA then allows tracking the mobile. See our material and user stories to know how Lyrtech development systems are used by world-class organizations developing Smart Antennas and MIMO systems. 4. Video: New generation FPGA are a top contender for high rate video processing. The Signal Master, with its family of analog and digital video boards directly connected to the FPGA and their system-level capability, allows to effectively implement FPGA and Simulink 4

5 designed video processes, and represents a unique video processing development platform. The very high processing throughput of FPGA based processing is thus harnessed and made available to advanced video developers. A video processing bundle comes along with an FPGA video-processing framework that handles the video data streams, including SDRAM buffering, line and block processing, etc., while these processes can be directly translated from Simulink models. More complex video understanding background processes run on the DSP. Also, numerous off-the-shelf C language DSP video processing libraries can be executed on the DSP, in which intensive processes sections will be ported on the FPGA. 5. Audio: The system allows the use of a GPIO-Audio board that brings the total number of inputs to 8 and outputs to 24. With such multi-channel systems, advanced immersive audio & 3-D surround can be developed, seldom with the use of the FPGA for as a co-processor for multi-channel processing such as real-time FFT analysis. Moreover, the design flow can integrate Simulink and Matlab. Advanced high-rate (above KHz) audio processes can thus be prototyped and throughfully validated. 6. VoIP Application: With the Virtex-II Pro FPGA (that includes PowerPC cores), a high-density (100 channels and more) DSP-FPGA VoIP system designer could integrate the following elements in the FPGA : - high-rate DSP functions to offload the DSPs - Network protocols with the embedded PowerPC - Communications controller for the network interface - Memory and bus interface controllers - Interface to the PCM serial data streams to offload the DSPs The software design of such a system has less restrictions than the classical approach, where the hardware would dictate how the software must be implemented. With an FPGA oriented solution, the hardware can be adapted to the requirements of the software designers. 7. Control/Industrial Application: The traditional control processing paradox of relatively slow control loops (by comparison to fields such as audio and wireless) and fast transient processing poses challenges to control system engineers. In this context, partitioned architecture where 5

6 an FPGA is combined to a mainstream GPP or DSP becomes a very interesting and effective solution. In one typical application, for example, a very high-rate (75 MHz) FPGA-based neural network robotic control system was developed using the DSP-FPGA architecture, providing a very effective solution only capable with this architecture. Conclusion The combination of DSPs and FPGAs provides to developer the ideal combination of classical DSP-based processing and very high-performance FPGA-based processing. At the same time, challenges in integrating these very different devices are addressed using system level tools. This combination can be applied very effectively to variety of signal processing fields. The Signal Master then, with its designed-in DSP-FPGA architecture, industry leading system level integration and application oriented demo and capabilities, is the ideal DSP/FPGA development platform on the market for demanding DSP system developers. 6

7 TI-XIlinx stuff FPGAs (in most cases) are a complementary, and not a competitive, solution to programmable DSPs in high performance real time signal processing systems. The TI DSP and Xilinx FPGA will allow designers to capitalize on two complementary technologies where they are best suited. Here is how TI and Xilinx are Partnering in the Market Place: Programmable DSPs are the classic answer to real time signal processing. They offer high-speed, real-time processing performance, low unit power consumption and affordable unit prices. Software programmability also makes them very flexible. FPGAs are increasingly used in real time signal processing. They offer very high performance (parallel processing), flexibility through programmable hardware and affordable cost for complementary functions. Complementary Solution FPGAs typically complement programmable DSPs in highperformance real-time systems in one or more of the following ways: System logic muxing and consolidation New peripheral or bus interface implementation Performance acceleration in the signal processing 7