Embedded Processor Watch

Editor: Jim Turley

In This Issue:

• IDT Tools Inexpensive MIPS Chips
• Sharp Spins Second Standalone ARM Chip
• Velocity Speeds ASIC Development
• Industry Resources: Computer "Anatomy" Book
• Industry Resources: Evening Sessions at Embedded Processor Forum
• Weird Product of the Week: MicroWeb

IDT Tools Inexpensive MIPS Chips

IDT's new RC64474 and '475 displace the company's current midrange chips, offering more performance, better floating-point precision, and lower prices. A good set of features, but one that will face tough competition from the likes of NEC and QED, both of which have made a strong showing lately with their new MIPS processors.

The '474 and '475 are software compatible with the R4700 but hardware compatible with IDT's R4640 and R4650, respectively. They have the same single-issue MIPS-III core and floating-point unit as the R4700, but the same external bus interface--including the pinout--of the R4640 and '50 chips. Thus, the new '474 and '475 are hardware upgrades for existing R4640 or '50 sockets, or cost savers for existing R4700 designs.

The 32-bit RC64474 sells for $27 to $59, while the 64-bit RC64475 lists for $38 to $68 (at 180 MHz and 250 MHz, respectively). Rather than discontinue the two older parts, IDT has dropped their prices, making the older chips about $30 cheaper, or about half the price, of the newer components. For the extra cash, the '474 and '475 offer twice the cache, double-precision floating-point, higher clock rates, JTAG, and support for Windows CE. The data cache can be set for either write-back or write-through updates on a page-by-page basis. Either cache's contents can also be locked, one half at a time.

IDT's two new chips ride into town just as the local population increased. New MIPS chips from fellow licensees QED and NEC appeared this year that staked their claim on the best price/performance territory. QED just freshened its line with the RM52x1 triplets (see Microprocessor Report 8/3/98, p. 11). The low-end RM5231 undercuts the price of IDT's '474 by a good $20 (33%) even though it has twice the cache. Paying IDT a $20 premium for R4640 socket compatibility will be a poor investment for most embedded designers.

The '475 is more evenly matched with QED's RM5261. At 250 MHz, the two sell for the same price (within $1) with similar FPUs, bus interfaces, power budgets, production schedules, and performance ratings, but once again QED offers twice the cache capacity.

Sharp Spins Second Standalone ARM Chip

As the trickle turns to a dribble, Sharp (http://www.sharpsma.com) has joined Atmel and Samsung in rolling out a standalone ARM7-based chip for embedded applications. The LH79402, optimistically named the "universal microcontroller" by Sharp, includes integrated peripheral logic that will make the chip suitable for various embedded systems when it ships in 1Q99.

In addition to the chip's 66-MHz ARM7TDMI core, the '402 has 8K of unified cache, a memory controller (for DRAM or SRAM), two UARTs, a two- channel DMA controller, three counter/timers, and as many as 40 general- purpose I/O pins. The device is housed in a TQFP-176 package.

The most unusual feature of the '402 is its programmable pin assignment. The chip's 176-pin package doesn't have enough I/O pins for all 64 of the processor's I/O signals, so users are allowed (required, actually) to decide which I/O signals will be routed to which pins by means of a programmable switch matrix inside the part. This crossbar switch's configuration is not persistent, and must be reprogrammed every time the processor boots, potentially allowing run-time customization of the chip's I/O assignments. Sharp has a patent pending on the implementation of its switch matrix.

The '402 complements Sharp's only other standalone ARM chip, the LH77790 (see Microprocessor Report 3/27/95, p. 9), which has a gray-scale LCD controller. Given Sharp's corporate emphasis on flash memories and LCD displays, future ARM-based chips with either or both seem likely in the near future. In the meantime, the $12 LH79402 makes a fine controller for general-purpose embedded systems that need moderate performance, low cost, and a flexible choice of peripherals.

Velocity Speeds ASIC Development

In other ARM news, VLSI Technology has inaugurated a program it calls Rapid Silicon Prototyping that should speed the development of ARM-based ASIC chips. Designers start with VLSI's "Velocity" board, which includes a special ARM7 processor, field-programmable logic, PCI and AMBA interface connectors, and evaluation copies of all the hardware- and software-development tools needed to get started.

The Velocity board is a kind of engineering Lego set that allows programmers and hardware engineers to experiment with different hardware configurations, address maps, I/O devices, and operating systems without committing thousands of dollars to ASIC development or waiting months for silicon to return from the foundry. When the board is completely configured, VLSI will, of course, help users convert it into a real ASIC. For small to medium-sized companies that are considering their first custom chip, VLSI's Velocity is a low-risk and relatively low-cost way to kick the tires before committing any career-threatening moves.

Industry Resources: Computer "Anatomy" Book

Bruce Shriver and Bennett Smith have created the most interesting technical book in some time: "The Anatomy of a High-Performance Microprocessor." Unlike most microprocessor texts, which describe older processors and focus on a pins-out perspective, this unusual book delves deep into the internals of AMD's latest microprocessor, the K6-2. It also includes chapters on platform (i.e., PC) architecture, memory technology, and platform optimization.

Published by the IEEE Computer Society, the book comes with a CD-ROM that includes a full hypertext version of the text, video clips of AMD engineers and executives talking about their chip, technical articles, specifications, and simulators. Check out the book's Web site, http://computer.org/books/anatomy, where you can order it for $49 ($44 for IEEE members).

Industry Resources: Evening Sessions at Embedded Processor Forum

The first annual Embedded Processor Forum is now only two weeks away (October 15-16), and plans are in place for two special "birds of a feather" affinity sessions to fill out the evening. Each session will start at about 7:00 PM, after the reception, food, and drinks in the Fairmont Hotel's Market Street Foyer. All Forum attendees are invited to attend.

Embedded benchmarks will be the topic in the California Room as Markus Levy, president of EEMBC (http://www.eembc.org) leads a discussion about the need for new benchmarks, how they could be administered, and what the benchmarks should test. Representatives from 22 microprocessor companies will be in attendance to take part in the debate and demonstrate their work so far.

Next door in the Valley Room the topic will be embedded development tools and how they might be--or should be--standardized. Forum attendees, tool vendors, programmers, and users will hash out ideas, strategies, concepts, pros, and cons.

Details of the Embedded Processor Forum, including 10 first-time chip announcements, are at http://www.MDRonline.com/events/epf99/em_conf.html. The Forum is followed by a pair of full-day seminars that cover embedded processors and DSP chips. You can register on the Web, or by calling MicroDesign Resources (Sebastopol, Calif.) at 707.824.4004.

Weird Product of the Week: MicroWeb

Ready for the latest in home appliances? Then consider the MicroWeb, a microwave oven that doubles as a TV and voice-activated computer. According to an article in the Wall Street Journal, NCR's Knowledge Lab in London has developed a home microwave oven with a 10-inch LCD screen on the door. Why? To check bank balances, surf the Web, read e-mail, or just watch television while your food spins. Barclay's Bank of England is reportedly seriously considering trials of the MicroWeb to encourage at-home banking. The system also has a touch-sensitive screen for those who prefer typing to dictation, and a bar-code scanner to keep track of packaged foodstuffs. The system runs Windows NT on a Pentium II, which explains how the food is heated.