Embedded Processor Watch

Editor: Jim Turley

In This Issue:

• IDT RC32364 is Tops in Price/Performance
• PowerPC EC603e Hits 300 MHz
• Silicon Graphics R5000 CPU for Embedded Use
• Mobile Pentium II Module Goes Embedded
• Embedded Resources: Book Covers Real-Time Modeling
• About Embedded Processor Watch

IDT RC32364 is Tops in Price/Performance

Integrated Device Technology (IDT) has produced the first 32-bit microprocessor to top 10 MIPS/dollar. The new RC32364 processor offers terrific performance for its price, drastically undercutting the best embedded PowerPC or StrongARM processors. IDT is revamping its midrange CPU line, starting with a redesigned R3000 processor core. The new core is an IDT-only derivative that first appears in the company's new '364 chip, sampling now.

The new part replaces IDT's existing--and rapidly aging--line of R3000 processors like the R3081 by offering far better performance and more features at a better lower price. The R3xxx family will continue, serving the lowest price levels while the newer R32364 is appealing for new designs. IDT's performance claims are, however, based on simulation and not actual measured performance.

The new 32300-series instruction-set extensions include conditional moves, cache prefetching, branch-likely instructions, and nonblocking loads. IDT also added a multiply-accumulate instruction, which is not part of any official MIPS instruction set but is de rigueur for any new CPU these days. In short, IDT's 32300 core has all the features of an R5000-series core except the 64-bit registers and ALU. IDT has found that the new features are more valuable to customers than the 64-bit data paths.

With claimed performance of 175 MIPS (based on Dhrystone 2.1) at 133 MHz, the RC32364 delivers more than 1.3 MIPS/MHz. This ratio seems somewhat high for a scalar MIPS design, which would generally yield about 1.1 to 1.2 MIPS/MHz. These numbers are simulated, even though IDT is shipping samples of the chip. The company doesn't believe actual scores will differ.

Though some may quibble over the performance, the R32364's modest price of $16.50 (for 10,000 pieces of the 133-MHz chip) is not in doubt. If IDT's performance estimates hold true, the '364 will deliver better than 10 Dhrystone MIPS per dollar, the first 32-bit processor we've tracked to reach this milestone.

QED's high-end RM5230 and NEC's VR4310 and VR5432--MIPS parts, every one--are the runners up with about 8 to 9 Dhrystones/dollar. IDT's own R3041 and R3081 chips (see Microprocessor Report 11/18/92, p. 23) are well below this level, a sign of their advancing age. Even Digital's famous StrongARM-110 falls well behind this mark, although it still excels in terms of power efficiency.

For straightforward, nonintegrated, unadorned microprocessors, the RC32364 has many competitors but no equal. It doesn't have the FPU of NEC's VR43xx chips, the pin-compatibility of the PowerPC EC603e, or the remarkable current conservation of StrongARM, but unless users have a particular antipathy toward MIPS chips, the '364 is the best bargain for around $15.

PowerPC EC603e Hits 300 MHz

Motorola has decorated the top of its family tree with a 300-MHz version of its EC603e embedded microprocessor (see Microprocessor Report 10/6/97, p. 8). The company's embedded line now matches the desktop PowerPC 603e clock-for-clock. As the desktop market for PowerPC moves to the PowerPC 740 and 750 chips, the 603e becomes Motorola's platform for high-end embedded systems.

The company now offers this chip in no fewer than seven speed grades, hitting every 33-MHz step from 100 MHz to 300 MHz. IBM has matched only a few of these clock speeds with its identical EM603e chip. All versions of the EC603e (and IBM's EM603e) are plug-compatible, except for differences in supply voltage.

The newest speed grade is much more expensive, relatively speaking, than its siblings. Whereas the slower EC603e chips sell for about $0.21 per MHz, the 300-MHz chip's $109 price works out to $0.36 per MHz. Like Intel with its Pentium II, Motorola charges a steep premium for its fastest part, out of all proportion to the chip's actual performance. This price is also not much of a discount from that of the full-featured PowerPC 603e, which sells for $135 at the same clock rate and quantities, but has a working floating-point unit.

While there aren't many embedded processors that cost $100, there are virtually none that run at 300 MHz. That price puts the EC603e in the same league as the R4700 or R5000 (see next item), both of which have working floating-point units but 50% slower clock rates with proportionally lower Dhrystone MIPS ratings. It is much cheaper, however, than the ridiculously overpriced 68060 (and 'EC060 and 'LC060) or Intel's 266-MHz Pentium II embedded module (see Microprocessor Report 6/1/98, p. 15). The PowerPC's cache snooping might give it a slight edge over the MIPS parts, but only if floating-point isn't needed. The EC603e offers much better integer performance for the price, but the MIPS chips are the only choice if floating-point code is used. For designers upgrading from other PowerPC chips, the new EC603e is a competitively priced top end to Motorola's high-end embedded lineup.

Silicon Graphics R5000 CPU for Embedded Use

IDT has repositioned its high-end MIPS processor, the R5000, from workstation sales into the embedded marketplace. The 200-MHz chip, which is still used in Silicon Graphics' entry-level O2 workstations, cranks out 330 Dhrystone MIPS, according to the company. At $130 (in 10,000- piece quantities), the part sells for about half its old price as a workstation engine.

The R5000 (see Microprocessor Report 1/22/96, p. 10) is bus-compatible with other midrange MIPS chips, specifically IDT's R4640, R4650 and R4700. Its large caches, second-level (L2) cache controller, and 64-bit synchronous bus interface give the chip plenty of high-end data bandwidth for networking applications.

As a workstation processor, the R5000 is showing its age. Its integer performance is well below that of Pentium/MMX--much less Pentium II--and its floating-point is about the same, based on SPEC95. Pentium, too, has a 64-bit bus, but far better software support. With Pentium prices now below $100, the R5000 is not a compelling value, even among MIPS processors. IDT's own R4650 sells for just $38, with many of the same features. NEC's new 250-MHz VR5464 (see Microprocessor Report 3/9/98, p. 1) has multiple execution units--including one for media extensions--and is a far better value, at $95, than the R5000. Silicon Graphics will soon replace its O2 workstations with systems based on Pentium II, so this is the end of the road for the R5000. Unless hardware designers need socket compatibility with other MIPS-IV parts, the R5000 is too expensive for the task.

Mobile Pentium II Module Goes Embedded

With a wave of its magic wand, Intel has transformed its 266-MHz Mobile Pentium II Module (see Microprocessor Report 4/20/98, p. 14) from a notebook PC product to an embedded product. The module itself is the same; only its life span has changed. As an embedded product, Intel guarantees embedded customers a longer product life (without being specific) than PC makers have come to expect.

The mobile/embedded module is the first P6-class processor to join Intel's embedded lineup. Its form factor and connector placement make it incompatible with the previous two embedded Pentium modules (see Microprocessor Report 6/23/97, p. 10) and with mobile Pentium modules for PC laptops. The module stands only 0.39 inches high, making it low enough to stack on standard VMEbus or CompactPCI cards. Pricing ($718 in 1,000-unit quantities) is unchanged from the PC version. We expect this 266-MHz module will soon be followed by many of the other P6 notebook modules by year-end.

Embedded Resources: Book Covers Real-Time Modeling

That's the subject of Bruce Powel Douglass's "Real-Time UML," a 400-page book published by Addison-Wesley. The book covers a standard notation-- the unified modeling language--that real-time developers can use to model the structure and behavior of systems. Chapters detail requirements analysis, object definition, behavior, mechanistic design, and other topics.

Copies of the book (ISBN 0-201-32579-9) are available in bookstores or at http://www.awl.com/cseng/titles/0-201-32579-9/.