Billy, didn't the DEC/Intel settlement give Intel access to the StrongArm chip?
Intel settop boxes don't necessarily need a Pentium in them...
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ARM optimizes its latest core for Windows CE
Peter Clarke
01/26/98
Electronic Engineering Times
Page 18
Copyright 1998 CMP Publications Inc.
Austin, Texas - Advanced RISC Machines Ltd. (ARM; Cambridge, England) is about to add to its arsenal its first processor core that supports the Windows CE operating system, as the company fights for design wins in consumer equipment.
A cached microprocessor core based on the ARM7TDMI will support the next release of Windows CE, which is due to be announced this quarter, said Eric Carpenter, Windows CE project manager for ARM, based here. The core is a new design, called ARM720, and is optimized to meet the demands of the stripped-down Windows OS, Carpenter said.
"It's the ARM7TDMI core plus the cache and memory-management unit required to run Windows CE well," he said.
Some industry observers are skeptical about the use of ARM cores with Windows CE, however. Even VLSI Technology Inc., an ARM licensee and part-owner of the company, has said it will offer a CPU interface on a future version of its ARM-based Vista chip set for set-top boxes to give customers the option of using a MIPS or other microprocessor.
ARM believes the ARM720 core could help move Windows CE into portable consumer applications, apart from the architecture's current strong position in handheld computers.
Some of ARM's semiconductor partners are familiar with the 720 and would be in a position to produce 720-based chips for OEM customers in the second quarter, Carpenter said. The same or similar functional blocks will be used to produce a more powerful version of the ARM9TDMI core that is optimized for Windows CE. Due in a few months, it will double the ARM720's performance, he said.
Windows CE is already running on the higher-performance StrongARM microprocessor, which was designed by ARM in collaboration with Digital Equipment Corp. The Windows CE port to StrongARM will be officially released alongside the port to ARM, but the future of the StrongARM architecture remains uncertain, since Digital sold its rights to the architecture to Intel Corp. along with most of Digital's semiconductor interests.
The ARM7TDMI, otherwise known as the Thumb, is a version of the 32-bit ARM7 CPU designed to work with instructions stored in a 16-bit format and expanded on-the-fly to the full 32 bits. The approach costs in performance but allows use of 16-bit-wide memory banks, saving approximately 30 percent in memory space compared with 32-bit ARM code. The Thumb approach has proved attractive in portable equipment because of power-consumption savings.
Microsoft necessities
Carpenter said the Windows CE cache is unified and 8 kbytes in size. He added that although ARM has examples of both MMUs and cache architectures in the form of predesigned blocks, designing the 720 was not a case of adding blocks off-the-shelf. "There were certain things Microsoft felt were necessary," he said. "For example, there were some specialized requirements for the MMU, some identification tagging designed to help Windows CE."
Carpenter added: "The 720 won't appear as a bare chip; we expect licensees to take it, put peripherals around it and offer tailored solutions."
Microsoft announced its plan to port Windows CE to the ARM family of processors in December 1996. "Windows CE is definitely making headway, so we need to be supported," Carpenter said.
However, analyst Andrew Allison, who publishes a newsletter called Inside the New Computer Industry, said, "I think ARM is not terribly well-placed with regard to Windows CE." In terms of handheld PCs and Internet-connected devices, he said, "It seems the ARM processors in their currently available implementations are not quite powerful enough. The leading architecture is MIPS, and that seems likely to dominate."
Indeed, Allison believes that "MIPS is poised to become the Intel architecture of the Windows CE business-that is, unless Intel wakes up and uses the StrongARM. Of course, with StrongARM they have a tremendous NIH [not invented here] problem to overcome.
"I do see ARM as very attractive for ultra-low-power applications. I think ARM is better going after smart cards, smart locks, deeply embedded low-cost applications."
Carpenter said the ARM7 port of Windows CE "performs better than MIPS and Hitachi processors" based on tests run by developers at Microsoft and third-party companies. He said the ARM720 core could yield a 60- to 100-Mips machine, depending on clock frequency.
"That's plenty of performance to run a palmtop PC or a smart phone, but probably not enough for a set-top box or subnotebook computer," he said. "For those applications, there will be the ARM 9 or StrongARM."
David Tahmassebi, director of marketing in VLSI Technology's consumer digital entertainment group, said that although the Vista 98 set-top chip set uses an embedded ARM7TDMI for system control and transport, a future integration of the control and decoder would be based on the ARM9TDMI core. At the European introduction of the chip set, Tahmassebi said the VES6900, due in the fourth quarter, will use 0.2-micron CMOS to get a clock frequency of more than 100 MHz and 100-Mips performance out of the ARM9TDMI.
But he also said it will include a bus for an external CPU. "Some customers want MIPS and some want [Hitachi's] SH. In Japan, particularly, the customers are MIPS-driven."
VLSI Technology is a licensee of Hitachi's SH-3. If a customer asked for it in sufficient volumes, Tahmassebi said, the ARM 9 could be stripped out and an SH put in as a replacement.
"We're starting to see designs that require 230-MHz microprocessors to get sufficient performance for future cable and satellite boxes," he said. |
