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Vol. II, No. 3 BDTI's DSP Insider March 2002
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This month:
*** DSP-Enhanced FPGAs: Altera vs. Xilinx
*** More DSP Performance for Motor Control
*** Avoiding Processor Selection Pitfalls
*** "Impulse Response," a news analysis and opinion column written
by Jeff Bier, BDTI's General Manager, and featured in EE Times
*** BDTI Announces New "Focus" Series--First Report: FPGAs for DSP
*** "Inside" Reports Analyze Hitachi/ST, ARM, and 3DSP
*** BDTImark2000(TM) for the Hitachi SH-4
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*** DSP-Enhanced FPGAs: Altera vs. Xilinx
On February 11, Altera introduced its all-new Stratix family of FPGAs.
These FPGAs feature hard-wired DSP logic blocks; each DSP block can
perform up to eight 9-bit, four 18-bit, or one 36-bit multiplications
per cycle, with optional accumulation of up to two results. The DSP
blocks also contain "pipeline registers;" using these registers
increases latency but allows the DSP block to operate at higher clock
rates--at over 250 MHz, according to Altera.
The main competitor for the Stratix family is the Xilinx Virtex-II
family of FPGAs already in production. Both product lines feature
hard-wired multipliers, optional Simulink-based DSP development tools,
on-chip terminating resistors, and support for numerous high-speed I/O
protocols. In contrast to the selectable data width and optional
pipelining and accumulation of the Stratix DSP blocks, the Virtex-II
family contains fixed-function 18-bit multipliers with no hard-wired
accumulators. Announced Virtex-II devices contain up to 168 18-bit
multipliers; announced Stratix devices contain up to 112 18-bit
multipliers.
Echoing the differences in the hard-wired multipliers, the two
families take differing approaches to on-chip memory; the Virtex-II
family provides uniform memory resources, while the Stratix family
provides varied and somewhat more complex memory resources. Virtex-II
devices contain 18 Kbit blocks of RAM, and each logic cell can
alternatively function as 16 bits of memory. In contrast, Stratix
devices contain 512 bit, 4 Kbit, and 512 Kbit blocks of RAM, but logic
cells are not intended for use as memory.
The first Stratix device, the EP1S25, is expected to begin sampling in
the second quarter of 2002, with full production expected in 2003.
The EP1S25 contains 25,660 "logic elements," 1.85 Mbits of RAM, and 10
DSP blocks, and will be priced starting at $125 for high-volume
orders.
*** More DSP Performance for Motor Control
On February 18, Analog Devices introduced a new line of mixed-signal
DSPs, the ADSP-2199x. These new DSPs are based on the ADSP-219x core
which contains a 16-bit data path with a single multiply-accumulate
(MAC) unit. The first two members of this family, the ADSP-21990 and
the ADSP-21991, target motor control applications: both include a
14-bit A/D converter, a three-phase PWM output, and other
control-oriented peripherals.
With a clock speed of 160 MHz, the ADSP-2199x is one of the fastest
DSPs to target motor control. Most other DSPs targeting motor
control, e.g., the Microchip dsPIC, the Motorola DSP568xx, and the
Texas Instruments TMS320C24xx, operate at much slower clock speeds--
typically around 30-40 MHz. Of course, most popular DSPs are
available at clock speeds of 100 MHz or greater, but these processors
do not include A/D converters and PWM outputs.
The main competition for the ADSP-2199x will likely be the TI
TMS320C28xx, which was announced last September. The 'C28xx is
similar to the '2199x in many respects: it contains A/D converters,
PWM outputs, and a single-MAC data path that operates at 150 MHz.
However, the 'C28xx differs from the '2199x--and from most DSPs--in
that it uses a 32-bit data path. This difference in data sizes makes
speed comparisons between the 'C28xx and the '2199x difficult, but the
wider data size gives the 'C28xx an advantage for applications that
require more dynamic range and/or precision than that provided by a
16-bit data word. The pricing of these competitors is certainly
similar; the '2199x is priced at $18.45 - $21.95, and the 'C28xx is
priced at $17.95 - $22.95 (both prices are for 10,000 unit orders).
The 160 MHz ADSP-21990 is sampling now, and is expected to enter full
production in the second quarter of 2002. The 160 MHz ADSP-21991 is
expected to begin sampling in the third quarter of 2002, and is
expected to reach production in the fourth quarter.
*** BDTI Case Study
This Month: Avoiding Processor Selection Pitfalls
As DSP applications grow more diverse, the processor requirements for
these applications are diverging. For example, high-volume, low-cost
applications push designers to select a processor primarily on the
basis of the bill of materials cost. In contrast, the selection of a
processor for a complex, cutting-edge product may be driven by
time-to-market, pushing a designer to favor ease of implementing
software over low materials cost. In response to these diverging
needs, processor vendors are introducing new processors at a rapid
clip.
These expanding options create opportunities to gain competitive
advantages, but they also place a heavy burden on system designers.
Typically, system designers are familiar with only a small subset of
available processors, and the time available for assessing new
processors is usually short. To make matters worse, processors are
often selected early in the design cycle, before requirements are
fully understood or even fully set. This is particularly true when
the application requirements are susceptible to changes, e.g., when
the marketing department is apt to change the functionality
requirements late in the design cycle. These factors often lead
system designers to overlook some of the most promising candidate
processors for their application.
BDTI can help companies avoid these common pitfalls by efficiently
identifying the most suitable processors for an application. Through
our experience in developing DSP application software, we understand
the processing requirements of a wide range of applications, and
through our experience in processor analyses, we are uniquely capable
of quickly evaluating a wide range of processors against these
requirements.
BDTI put its expertise and methodology to work recently by helping a
major consumer electronics manufacturer identify processors suitable
for a range of next-generation digital audio products. BDTI used its
experience in developing digital audio applications to identify the
essential requirements of each product. We then turned to our
database of processor analyses to identify promising candidates, and
recommended specific processors for each product based on a custom
analysis.
To learn how BDTI's DSP expertise can be applied to help you select a
processor for your DSP application, please contact Jeremy Giddings at
BDTI (giddings@BDTI.com).
*** Impulse Response, by Jeff Bier
MPEG? No, Thanks.
Microsoft and Real Networks must be thrilled. This February, Apple
immediately followed the unveiling of its QuickTime 6 media player and
QuickTime Broadcaster with an announcement that these products were on
hold indefinitely. At issue were the proposed licensing terms for
MPEG-4 video, a key component of these products. These licensing
terms, announced in February, require content providers to pay a
royalty for every second of MPEG-4 video downloaded, streamed over a
network, or distributed on pre-recorded media. In Apple's view, this
"pay-per-view" fee structure is not a realistic match for the business
realities of streaming video.
Apple's rejection of the proposed licensing terms is particularly
notable because of Apple's long-standing involvement with the MPEG-4
standard. For example, the MPEG-4 file format is based on Apple's
QuickTime file format. When one of MPEG-4's loudest cheerleaders
balks at the licensing terms, it suggests that the process of bringing
the standard to market has gone horribly awry.
Indeed, the controversial licensing terms are but one of the
complications awaiting would-be MPEG-4 implementers. Despite the
common perception that MPEG-4 is a single standard, it is more like a
library of standards. The video standards alone describe nineteen
"profiles," each with a unique combination of algorithms, resolutions,
and so on. This complex scheme makes it difficult for system
designers to assess the cost of implementing MPEG-4, particularly the
licensing cost. The recently announced MPEG-4 video license, for
example, covers only two profiles; implementing other profiles
requires negotiating with up to nineteen patent holders.
Despite the uncertainty surrounding MPEG-4, it has already gained
acceptance in many streaming media applications. However, as Apple VP
Phil Schiller said in a recent interview, "This is a nascent industry;
we're trying to kick it off, trying to get it started and we don't
need to put roadblocks in the way for people -- [these royalties]
would be a major roadblock." Indeed, one must wonder if the proposed
MPEG-4 royalties will kill the streaming media goose before it lays a
single golden egg.
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*** BDTI Announces New Series: "Focus" Reports
*** First Report Focuses on FPGAs
BDTI is pleased to announce the launch of a new series of reports,
"BDTI Focus Reports." Volumes in this new series will focus on a
particular technology for implementing digital signal processing--as
in the first report on FPGAs--or a single application with heavy DSP
requirements--as in future reports on wireless communications and
multimedia. These reports will provide timely, concise evaluation and
options for developers and users of DSP.
The first report in this series, "FPGAs for DSP," investigates the
capabilities and DSP design flows of leading DSP-oriented FPGAs. The
report analyzes the DSP performance of these devices and compares
this performance to that of leading DSP processors. The report also
compares FPGAs to competing solutions such as ASICs and assesses the
strengths and weaknesses of FPGAs compared to the alternatives.
Watch for details on this and other "Focus" reports at BDTI's Web
site -- http://www.BDTI.com.
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*** "Inside" Hitachi/ST, ARM, and 3DSP
BDTI will soon release its report on Hitachi and STMicroelectronics'
newest cores. "Inside the Hitachi/STMicroelectronics SH-4/ST40 and
SH-5/ST50" provides in-depth DSP performance benchmarks and detailed
analysis of these two processor families. This report will satisfy
systems designers and engineering professionals who want insights into
the latest designs from STMicro and Hitachi targeting volume
applications such as set-top boxes.
For excerpts from the analysis and sample benchmarks, go to
http://www.BDTI.com/products/reports_SH4_SH5.htm.
Now shipping:
==> "Inside the ARM ARM7, ARM9, and ARM9E"
BDTI's analysis of the DSP capabilities of three ARM cores, the
widely-used ARM7, the newer ARM9, and the ARM9's DSP-enhanced
sibling, the ARM9E.
==> "Inside the 3DSP SP5"
BDTI's evaluation of 3DSP's fixed-point SP5 processor core with
SuperSIMD(tm), combining a superscalar architecture with SIMD.
For a sample of a BDTI "Inside" report, look on BDTI's Web site at
http://www.BDTI.com/articles/info_articles.htm#summary_reports.
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*** BDTImark2000(TM) for the Hitachi SH-4
BDTI has released a BDTImark2000 score for the Hitachi SH-4.
For this score, as well as BDTImark2000 and BDTIsimMark2000 scores for
other processors, go to www.BDTI.com/bdtimark/BDTImark2000.htm.
The BDTImark2000 is a summary measure of DSP speed distilled from a
suite of DSP benchmarks developed and independently verified by BDTI.
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*** About BDTI
BDTI is an independent source for DSP technology analysis and
optimized DSP software. From rigorous analyses of processors for DSP,
such as the "Inside" series of processor analyses, to highly regarded
technology training classes, BDTI is the trusted independent source
for reliable information on DSP technology. For highly optimized DSP
software, from specialized DSP library functions to complete
applications for processing-intensive applications, such as streaming
media, on general-purpose or DSP processors, BDTI provides quality and
precision work.
For more information, visit our Web site at http://www.BDTI.com.
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The next issue of BDTI's "DSP Insider" is coming in April. Previous
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BDTI's DSP Insider (c) 2002 Berkeley Design Technology, Inc.
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