AltiVec: the DSP shot heard around the world

Single-board digital signal processor makers are lining up to embrace the next-generation Motorola PowerPC microprocessor for DSP applications, but established DSP providers Analog Devices and Texas Instruments are countering with improved versions of their successful offerings

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Single-board digital signal processor makers are lining up to embrace the next-generation Motorola PowerPC microprocessor for DSP applications, but established DSP providers Analog Devices and Texas Instruments are countering with improved versions of their successful offerings

By John Rhea

Digital signal processing is entering a new generation. Parallel efforts by the Analog Devices Computer Products Division in Norwood, Mass., Motorola Semiconductor Products Sector in Austin, Texas, and Texas Instruments Semiconductor Division in Sherman, Texas, are pushing digital signal processor (DSP) technology into new computationally intensive applications and blurring the distinction between traditional microprocessors and DSPs.

Each of the three major chip producers — Analog Devices, Motorola, and Texas Instruments — is working from a roadmap of its own that envisions a continuing sequence of performance enhancements. Their work aims at capturing growth segments of dynamic commercial markets for mobile communications and portable computing. In the process, these companies are creating a technology base available and of immediate interest to military and aerospace systems designers.

The spotlight at the moment is on Motorola`s AltiVec chip, which not only adds vector processing features to the company`s popular PowerPC microprocessor line, but also is "the most powerful floating point engine on the planet," claims Will Strauss, president of the Forward Concepts market research firm in Tempe, Ariz.

The AltiVec (Alta for "high," Vec for "vector processing" — rumored to have been Motorola`s fifth choice for a trademark name) is also designated the G4 — the company`s fourth generation device in the PowerPC family. Leaders of Analog Devices and Texas Instruments are countering with fourth-generation products of their own.

Designers of military and aerospace systems stand to benefit from this flourishing competition as the high volume of the commercial markets drive prices rapidly down the experience curve. Strauss estimates that the military market represents less than 5 percent of total DSP industry revenues. Moreover, he says, prices of the state-of-the-art chips being introduced now should eventually tumble to the hundred-dollar range.

This is good news for the board vendors, and three of them have already committed products to the AltiVec, says Will Swearingen, director of PowerPC marketing at Motorola. They are DY 4 Systems of Kanata, Ontario, and Mercury Computer Systems and Sky Computers, both in Chelmsford, Mass. About 10 companies in all have decided to use the new chip since Motorola unveiled the technology in May 1998 and began sampling the chips among its most active customers earlier this year, he adds.

Analog Devices and Texas Instruments are not going to take this lying down, Strauss says, and they have not. At Texas Instruments, which he estimates accounts for at least half of the military DSP market and where "DSPs are a religion," the company is moving into a new generation of its own. This is the TMS320C6x family, which Texas Instruments leaders call the "universal DSP platform." Tom Smith, Texas Instrument`s strategic marketing manager, says the TMS320C6201 fixed-point and TMS320C6701 floating-point DSPs should begin shipping in production quantities later this year.

The Texas Instruments roadmap looks toward a next-generation TMS320C6x product line late next year, Smith adds. These are all pin-compatible with the earlier TMS320C2x and TMS320C5x generations — just as the AltiVec is pin-compatible with the previous PowerPC generations — and share a common software toolset. Smith`s roadmap shows a four-step evolution for the TMS320C62x from 1.6 billion instructions per second (1,600 MIPS) for commercial grade and 1,200 MIPS for military parts to 3,200 and 2,400 MIPS, respectively, over the next few years. The TMS320C67x is also expected to evolve in four steps from 1,000 and 840 million floating point operations per second (megaflops) initially to 3,000 and 2,400 megaflops for the commercial and military grades. "We coexist today with the PowerPC and we`ll coexist with the AltiVec," Smith comments.

Engineers at Analog Devices, meanwhile, are building on their large installed base of Super Harvard Architecture Computer (SHARC) DSPs, starting with their new 21160 for military designers and then delivering of the improved TigerSHARC later this year. The 21160, a 100 MHz device capable of fixed- and floating-point operation, targets such high-performance multiprocessing applications as radar, sonar, and medical imaging using single-instruction multiple-data parallel processing.

The TigerSHARC, which company officials call the "linchpin technology" in their signal processing portfolio, also is capable of fixed- and floating-point operation. Designers are aiming the device at telecommunications markets, says Colin Duggan, product marketing manager at Analog Devices. Duggan estimates that about one-third of 21160s go into military applications, and points out that military board producers are also evaluating the TigerSHARC.

The new TigerSHARC represents the third generation of DSPs at Analog Devices, Duggan says. In February company leaders unveiled a few technical details of their fourth-generation contender: a joint venture with Intel Corp. of Santa Clara, Calif., to create yet another compatible chip. A combined design team of engineers from the two companies is at work in Motorola`s backyard in Austin, Texas. Their goal is to create a low-power DSP core aimed at the markets for processing video, image, voice, and data in emerging embedded communications and Internet appliances.

This emphasis on low power in its own fourth generation DSP amounts to a response on the part of Analog Devices to Motorola`s AltiVec. The Motorola chip requires higher power than the TigerSHARC, Analog Devices officials claim, and really aims at applications such as Apple computers rather than hand-held uses. Among the applications that Duggan says would be appropriate for the new Analog Devices-Intel DSP (as yet unnamed, at least outside the development team) include a radar on the back of a Humvee or in an unmanned aerial vehicle (UAV).

One of the early users of the AltiVec will be DY 4, where Lynn Patterson, DY 4 vice president for product development, cannot hide her enthusiasm for it. "The AltiVec is a top-notch performer and runs faster benchmarks for FFTs [fast Fourier transforms]," she says. "The AltiVec is the tip of the iceberg," she adds. "One DSP is never enough to do the job. Sometimes you need four, sometimes 50. We live close to the sensors front end."

Patterson stresses that the users need all the DSP power they can get because their budgets and time scales get crunched. Building on the PowerPC and using C code provides ease of use. Yet she cautions that the AltiVec will need hand-coded libraries to make the most of all its power. In evaluating her suppliers, Patterson says Analog Devices had the upper end of the market with the SHARC. Yet she points out that Texas Instruments captured market attention with the TMS320C6x line, which is strong now. Nonetheless, she comments, "Analog Devices still has some tricks up their sleeve."

DY 4 engineers were among the recipients of AltiVec sample chips and already have what they call a "G4 ready" single-board computer with dual PMC interface incorporating 400 MHz PowerPC 750s, the SVME/DMV-79. The company also has a foot in the Texas Instruments camp with a quad TMS320C6x DSP board featuring the common heterogeneous architecture for multi-processing (CHAMP) configuration from its Ixthos subsidiary in Leesburg, Va. Patterson says she is also looking at the Analog Devices-Intel joint venture, but believes that those parts will be more for the commercial market rather than the 6U VME base of DY 4. "Although product specs may evolve," she adds.

Another announced AltiVec potential user is Mercury Computer Systems, says Richard Jaenicke, manager of product marketing at Mercury. Jaenicke calls the AltiVec "a leap forward," and estimates the addition of vector processing to the reduced instruction set computer (RISC) core to yield an improvement by a factor of four to five in signal processing. He cites such applications as UAVs, where performance density is critical, and synthetic aperture radars (SARs), where "you want to do more processing close to the sensors."

Mercury engineers have also been sampling AltiVec chips. Jaenicke says the new DSPs are just what firms like his have wanted. He expects to begin shipping products incorporating the chips toward the end of this year. "We can do new things," he says, such as adaptive processing in radar. "For space time adaptive processing [STAP] it would take a thousand processors today to do the job in real time, and that`s too large to fly." It would mean four large VME 9U chassis, and he wants to do the job with one 9U chassis.

In that regard, Mercury announced in June that it had won a $11 million contract from Raytheon Systems Co. of El Segundo, Calif., to provide its Race multicomputer systems for advanced SARs in the U.S. Air Force`s U-2 reconnaissance aircraft. The heart of the multicomputer systems will be Mercury boards populated with PowerPC RISC processors.

"We like using RISC for DSP," Jaenicke says. "It`s easier to program and more tools are available." He sees what he calls a "convergence" in which "DSPs are getting more RISC-like." Mercury intends to implement AltiVec in three areas: PCI boards, VME systems, and high-density multi-chassis systems, Jaenicke says. "The key to getting good performance from the AltiVec is to know the internals of the processing and instruction set — not just add and multiply, but how you get the data in and out and how to move it around and execute the instructions."

Craig Lund, a technology consultant to Mercury in Durham, N.H., calls the Motorola chip "a shot across the bow" of the DSP industry. It is a high-end processor now for applications like the Apple computers, but he looks for a next generation of integrated processors. That is the Intel strategy, he says, and he stresses that process technology permits more transistors per die, not more pins of input/output. "The DSP and microcontroller will be indistinguishable in a few years," Lund concludes.

Designers at another major DSP user, CSPI in Billerica, Mass., have also been sampling AltiVec chips and are looking for improvements in density, cost, and power consumption for commercial off-the-shelf (COTS) solutions that foster technology insertion. James Waggett, vice president for advanced development at CSPI, envisions new applications such as adaptive computing (where "you will run out of dollars before you run out of performance"), automatic target recognition, speech processing ("who`s speaking?"), processing of fractals ("my tank? their tank? fake tank?"), and security applications that are too expensive to do with today`s technology.

CSPI has a roadmap of its own, says Bernard Pelon, CSPI director of product research. It closely tracks Moore`s Law (the formulation of Intel founder Gordon Moore that processing speed doubles every 18 months at no increase in cost). Starting with the Intel i860xp in 1990 at a clock speed of 40 MHz and processing speed of 120 megaflops, on to the PowerPC 603 in 1994 at 200 MHz and 400 megaflops, to the PowerPC 750 at 300 MHz and 600 megaflops, and finally this year to the G4 at 400 MHz and 3,200 megaflops. To do the jobs that Waggett has in mind means extrapolating that line forward in time along the path established by Moore.

One of the things that CSPI brings to the party is libraries of operating systems and applications programming interfaces. Sharon Sacco, lead engineer, stresses that these libraries are available to all of the company`s customers at no cost. The company is working on these libraries now, she adds, so that users will be able to take advantage of the AltiVec immediately. The three libraries are:

(1) Industry Standard Signal Processing Library (ISSPL), which consists of 249 optimized functions used in signal and image processing applications. All compute-intensive functions are assembly language-coded to achieve the shortest execution time.

(2) Vector, Signal, and Image Processing Library (VSIPL), which supports high- performance computation on dense rectangular arrays. This object-oriented library provides the application developer with signal and image processing functions, including FFT and filter routines for vector and matrix processing and basic functions in linear algebra processing.

(3) Message Passing Interface (MPI) parallel program library, which provides multiprocessor control and interprocessor communication. This library of 128 functions provides a simplified way for the programmer to associate specific data with specific processes.

Sky Computers, meanwhile, announced a VSIPL of its own last month in an attempt to reduce development time and ensure application portability across platforms, between vendors, and to new technology. VSIPL is a result of a standards effort at the Defense Advanced Research Projects Agency in Arlington, Va., to eliminate the need for users to re-code function calls. The company earlier announced an MPI library in June.

Pioneering another way to ease the transition into DSP-populated boards is Spectrum Signal Processing of Burnaby, British Columbia. The joint effort with Analog Devices using that company`s SHARC 21160 is called the "EZ-LAB Evaluation Board." The idea is to get evaluation hardware into the hands of engineers so they can get a head start on their designs, explains Graeme Harfman, SHARC product line manager at Spectrum.

Under the arrangement disclosed in April Spectrum engineers will design and manufacture the evaluation boards to be sold by Analog Devices. Analog Devices will provide support to the OEM buyers, Harfman notes, and Spectrum will support the high volume board customers. Spectrum experts have been using the previous generation SHARC 21060s and is now readying a complete line based on the 21160 to hit the market late this year encompassing PCI, VME64, CompactPCI, and PMC configurations. The company`s line spans low-end single-processor PCI versions up to 18-chip complex boards for such demanding applications as radar.

Ron Marcus, marketing director at Synergy Microsystems of San Diego, also sees a convergence of DSP and general-purpose processing functions. The company has used 604 PowerPCs, which he describes as "getting a little long in the tooth," and in June launched a new VME board, the VSS4, with four PowerPC 750 processors that deliver as much as 3.7 gigaflops of performance. But already Marcus is getting ready for the AltiVec. The VSS4 was designed from the beginning to use the vector processing unit when it becomes available later this year.

"Everybody in the VME and PCI world wants to do AltiVec," Marcus asserts. He notes that it is the same general configuration as the G3 PowerPC 750 with just one pin different and much software in common. "With a dedicated DSP, you have to write custom code," he adds. Nonetheless, he sees plenty of life left for the 750. "It`s still the best bet for general-purpose processing," he comments.

Engineers at Catalina Research Inc. of Colorado Springs, Colo., is focusing on front-end DSP functions with a family of VME 6U boards using a company-developed algorithm-specific DSP chip. These boards — the Gemini and Scorpio — will handle "a fire hose of data," says Michael Bonato, Catalina director of marketing.

Bonato`s point is that these optimized chips, surrounded by random access memory, are necessary up front for complex radar, spectrum-analysis, and signal-intelligence applications; the PowerPCs and AltiVecs are best used downstream.

At Transtech DSP of Ithaca, N.Y., general manager Andy Stevens says of the AltiVec, "We`re more than ready for it." The company, which has used Texas Instruments TMS320C4x and Analog devices 21060 and 21062 SHARCs in the past, is also in development of new boards incorporating the 21160 and TigerSHARC. But Transtech`s newest product, the TPE3, is based on 300 MHz PowerPC 750s as part of a family with a common architecture and programming tools. The company is targeting PCI, PMC, and CompactPCI.

Rodger Hosking, vice president of marketing at Pentek Inc. of Upper Saddle River, N.J., describes his company as traditionally a Texas Instruments house and stresses the support he gets from that supplier. Pentek engineers use floating point devices for their embedded systems, and Hosking says he needs that flexibility. "We`re not closing the door on the AltiVec," he comments, "but we have to do our homework first." He raises the question of how efficient the PowerPC family is when the user has to go off chip to fetch data from memory. "It`s OK if it`s in the cache," Hosking notes, but he wonders if the PowerPC line is sufficiently optimized for real-time environments.

Radstone Technology PLC of Towcester, England, is also readying products based on the AltiVec. Yet Radstone officials are not aiming their AltiVec products at high-end DSP applications, says Stuart Heptonstall, Radstone product manager for DSP and graphics. The company is focusing on rugged DSP board-level products based on the SHARC 2016 to meet extended temperature, shock, and vibration environments. The DSP-RISC combination is acceptable for low- and medium-performance applications, Heptonstall notes, but the problems arise when the devices have to be scaled up.

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Paavola: use all the DSP tools available

CHELMSFORD, Mass. — Developers of high-performance multiprocessor systems for signal processing applications have two choices, claims Steve Paavola, marketing manager at Sky Computers in Chelmsford, Mass. — specialized DSP chips, or conventional microprocessors based on the reduced instruction set computer (RISC) architecture.

DSPs and RISC microprocessors have evolved over the years since the original Intel i860 — which was not a DSP chip — provided excellent floating point performance and thus was able to perform DSP functions. The SHARC family from Analog Devices was the first competitor, generating more power on the same board size and delivering what Paavola describes as "a significant performance boost for the size/watt/dollar," he says.

Motorola`s PowerPC family was the first RISC processor with sufficiently low power consumption and high performance to replace the i860 for use in high-end signal processing applications, he says. The family evolved with higher clock rates and better memory bandwidth, and the next step will be the AltiVec.

"When AltiVec starts shipping, a new generation of even higher capability PowerPC-based systems will become available," Paavola notes. "The AltiVec instruction set was specifically designed to provide the PowerPC with enhanced signal processing (and graphics) capabilities. AltiVec will enable a 200 gigaflop system to fit easily into a single chassis."

Applications that require just a few of the low-power DSPs include digital radios, some medical imaging applications, and simple radar and sonar systems. Applications like synthetic aperture radar, space time adaptive processing, and signal intelligence can use hundreds, even thousands, of these processors.

Paavola cautions designers, however, to pay attention to memory design, managing input/output and inter-processor communications, and software design. "A successful implementation must address all of these issues," he concludes.

Sidman: still a place for specialized DSPs

SOUTH PORTLAND, Maine — Specialized military applications call for specialized digital signal processors — not conventional RISC microprocessors, insists Steven Sidman, vice president for marketing at Quadic Systems Inc. in South Portland, Maine.

Historically, this has been the case, and remains so despite the growing popularity of general-purpose microprocessors and DSPs that are becoming increasingly available from the commercial market, he says.

The specialized chips of the past were fabricated with earlier processing technologies (1.5 micron, two-metal) vs. today`s 0.18 micron and even smaller geometries and such new features as copper interconnect. Yet, Sidman says, some of their architectures, particularly their optimization to do fast Fourier transforms, could be reproduced today with modern fabrication techniques and outperform today`s general-purpose devices.

"There is a place for special-purpose architectures, even in today`s COTS [commercial off-the-shelf] environments for particular, well-defined tasks," he says. "These tasks will generally consist of a fixed set of operations that are performed repeatedly on continuous streams of very high-speed data."

Moreover, Sidman contends that long-term military programs may be able to retain the form, fit, and function at the system level for many years by re-fabricating some of the specialized components with more modern processes. The packaging is likely to remain the same, he says, and the development costs can be minimized. Also, the software can be reused, which saves cost and minimizes the risk associated with changing it.

DSP providers

Catalina Research Inc.

1321 Aeroplaza Dr.

Colorado Springs, Colo. 80916

Phone: 719-637-0880

Fax: 719-637-3839

Web: www.cri-dsp.com

CSPI

40 Linnell Circle

Billerica, Mass. 01821

Phone: 978-663-7598

Fax: 978-663-0150

Web: www.cspi.com

DY 4 Systems Inc.

333 Palladium Dr.

Kanata, Ontario, Canada K2V 1A6

Phone: 613-599-9199

Fax: 613-599-7777

Web: www.dy4.com

Ixthos Inc.

741-G Miller Dr., S.E.

Leesburg, Va. 20175

Phone: 703-779-7800

Fax: 703-779-7805

Web: www.ixthos.com

Mercury Computer Systems Inc.

199 Riverneck Rd.

Chelmsford, Mass. 01824

Phone: 978-256-1300

Fax: 978-256-3599

Web: www.mc.com

Pentek Inc.

1 Park Way

Upper Saddle River, N.J. 07458

Phone: 201-818-5900

Fax: 201-818-5904

Web: www.pentek.com

Radstone Technology PLC

Water Lane, Towcester, Northants, England NN12 6JN

Telephone: +44 (0) 1327 359444

Fax: +44 (0) 1327 359662

Web: www.radstone.co.uk

Sky Computers Inc.

27 Industrial Ave.

Chelmsford, Mass. 01824

Phone: 978-250-1920

Fax: 978-250-0036

Web: www.sky.com

Spectrum Signal Processing

8525 Baxter Place—#100

Burnaby, British Columbia, Canada V5A 4V7

Phone: 604-421-5422

Fax: 604-421-1764

Web: www.spectrumsignal.com

Synergy Microsystems

9605 Scranton Rd.—#700

San Diego, Calif. 92121

Phone: 858-452-0020

Fax: 858-452-0060

Web: www.synergymicro.com

Transtech DSP

20 Thornwood Dr.

Ithaca, N.Y. 14850

Phone: 607-257-8678

Fax: 607-257-8679

Web: www.transtech-dsp.com

Vmetro Inc.

1880 Dairy Ashford—#535

Houston, Texas 77077

Phone: 281-584-0728

Fax: 281-584-9034

Web: www.vmetro.com

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