32-bit controllers hit the mainstream

32-bit controllers hit the mainstream
By Martin Gold, EE Times
March 25, 2002 (1:28 p.m. EST)
URL: http://www.eetimes.com/story/OEG20020322S0100

SAN FRANCISCO — Once confined to a few niche markets, microcontroller vendors are suddenly clamoring to take the lead in offering general-purpose MCUs based on 32-bit processor cores — a trend that promises to raise the performance bar, at minimal cost, for a range of embedded systems.

Now that 0.18-micron process technologies have matured, chip vendors are packing general-purpose peripherals and, often, flash memory around some well-known 32-bit cores and pushing them out into the open market starting this year. "Today's new high-end microprocessors will be tomorrow's new microcontrollers," said Hank Pawlowicz, marketing manager for the system-LSI business unit at Hitachi Semiconductor America.

It's still too early to predict which of the MCU platforms will dominate the 32-bit domain in the same way that Intel's 8051 and Motorola's 6805 captured the bulk of early 8-bit design wins. ARM Ltd. has a host of backers, including Atmel, P hilips, Sharp and Oki. Intel Corp. is backing its own version of ARM, known as Xscale, which grew out of the StrongARM processor. But Hitachi Ltd.'s SuperH, in use at STMicroelectronics, and Motorola Inc.'s PowerPC-based MPC5XX, due in April, are coming on strong.

Until now, 32-bit microcontrollers have been tied to a narrow range of applications: Chip vendors would tailor their architectures and peripheral sets for a few big customers who needed higher performance than they could get from the more common 8- and 16-bit microcontrollers. Otherwise the 32-bit processors did duty as standalone devices or as embedded ASIC cores.

ARM-based cores have found wide use in portable communications and handheld computing. Hitachi's SuperH has been used in digital video cameras; DVD players; and heating, air-conditioning and ventilation systems. Motorola's 32-bit MCUs are the de facto standard in automotive applications.

There is a "blurring of the microprocessor/microcontroller boundaries in applications s uch as automotive, networking, security and industrial control," said Kevin Klein, standard-products marketing manager for Motorola's 32-bit Embedded Controller Division.

"As the price delta between an 8-bit and 32-bit gets reduced by Moore's Law, then the market reach of 32-bit devices gets bigger," concurred John Rayfield, director of R&D for Cambridge, England-based ARM. "The area of an ARM7 core is small, and that incremental cost of putting it on a die is very tiny."

Indeed, many of the same licensees that have long been using the ARM7 as an embedded CPU in ASICs now plan to implant the core in general-purpose microcontrollers. Moreover, ARM's robust tool support and standard architecture are swaying chip vendors to drop their proprietary cores.

Oki, for one, "is drastically changing its focus to ARM-related products for the 32-bit microcontroller market," said Yoshi Aida, product-marketing manager for Oki Semiconductor, which recently announced a low-cost MCU based on the ARM7. "A prop rietary CPU core, to the engineers, feels like an isolated island. If a company wants to change from, say, a Hitachi 16-bit chip to a Motorola 32-bit chip, that requires a lot of software porting. Basing their code on ARM offers companies a lot of choices."

Rushing the stronghold

But ARM proponents will have their work cut out for them as they try to compete with big MCU suppliers like Motorola, which already has a long history supplying 32-bit controllers and plans to come out with its own general-purpose devices. One of its strongholds is in automotive, where the MCUs are used for engine and dashboard control. That is the market at which Hitachi will aim a new SuperH spin due for introduction late this year or early next.

Fred Shlapak, president of Motorola's Semiconductor Products Sector, said that it won't be easy for newcomers to break into the automotive market. Design cycles are exceptionally long, and customers aren't always kind to walk-ins. "You have to get a lot of scars on your back before you can get in that business," he said.

The recent Embedded Systems Conference here suggested that ARM has momentum going for its architecture in the 32-bit race. Philips Electronics (Eindhoven, Netherlands) said at ESC that it will have its first 32-bit MCU based on the ARM7TDMI-S ready for market in the fourth quarter. Sharp unwrapped two new 32-bit system-on-chip devices at ESC based on ARM7 and ARM9 cores.

Atmel Corp. (San Jose, Calif.) unveiled four ARM7-based microcontrollers at ESC. And Cirrus Logic Inc. (Austin Texas) used ESC to unwrap a family of ARM7-based microprocessors that run at clock speeds up to 90 MHz. It was learned that the company is developing a 32-bit MCU based on the ARM920 core with 64 kbytes of flash and a DSP multiply/accumulator on-chip, along with ports for Ethernet and USB. It's targeted for third-quarter release, according to a company source.

Geoff Lees, director of marketing for the microcontroller business line for Philips Semiconductors (Sun nyvale, Calif.), said Philips will have a range of standalone ARM7-based embedded controllers built on what he called a common system architecture. Derivatives will be created with peripheral, memory and package options.

Philips will use its 0.18-micron embedded-flash technology, which enables operation down to 1.2 volts and is said to deliver major improvements over the current 0.25-micron, 2.5-V industry standard. Lees said this technology will lead to faster processing throughput, a doubling of on-chip memory density, higher I/O bandwidth and lower power consumption.

Other ARM licensees such as STMicroelectronics Inc. and Fujitsu Ltd. indicated they too might offer ARM-based microcontrollers in the future, depending on how the market develops. For now, STMicroelectronics (Lexington, Mass.) is firmly supporting the Hitachi SuperH core for its 32-bit microprocessor offering, the SH4-based ST40RA166.

ARM's-length view

"We're closely watching what the market will be doing with t he ARM core," said Richard Steele, North American product-marketing engineer for microcontrollers at STMicroelectronics. "We do plan to have offerings in more than one camp."

To keep costs to a bare minimum, some vendors are eschewing flash memory in their MCUs to avoid paying higher manufacturing and testing costs. Oki's new ARM7-based ML67400, for example, doesn't include flash but does pack a 10-bit A/D converter and costs just $4.95 in 10,000 units or more.

The same message came from Sharp Microelectronics (Camas, Wash.) during ESC. Neither the ARM7-based LH79520, which is about to be released to production, nor the 200-MHz LH7A400, based on the ARM922T core and scheduled to be available in July, carries flash memory on-chip. Among the features of the Sharp devices is on-chip LCD control.

"The issue is cost," said Douglas C. Jones, application-engineering manager at Sharp. "Putting flash on-chip now requires an 0.18-micron flash process for 32-bit devices. But it's costly. For devices withou t flash, we could use a 0.25-micron process, resulting in a lower-cost device."

Sharp will price its LH79520 devices at $9 each in large volumes. The LH7A400 will be priced in the $12 to $13 ballpark in lots of 100,000 pieces.

Besides having a long list of tool support and a common architecture, another benefit of ARM-based MCUs is that they connect through the Amba on-chip bus. "We may have customers that need a certain feature and want to plug in their own logic or intellectual property," said Oki's Aida. "They can do that using the Amba bus and still be very fast to market."

From specific to general

But ARM is far from the only show in town. Top MCU supplier Motorola plans to weigh in with its own general-purpose 32-bit offerings in the MPC5XX line, which is now targeted specifically at automotive applications. Motorola says is getting ready to deliver these PowerPC-based MCUs for general distribution.

The MPC565 and MPC563 will have as much as 1 Mbyte of on-chip flash; the MPC561 does not have flash. The 565 will be available at the end of April; the 561 and 563 will be in production at the end of June. Motorola will also field general-purpose microcontroller versions of its ColdFire microprocessor later this year, said Klein of the Embedded Controller Division.

Also aggressively pursuing new 32-bit MCU applications is Hitachi Semiconductor America (San Jose) with the SuperH architecture. At ESC, Hitachi unveiled its 32-bit single-chip RISC MCUs, the SH7144 and SH7145, which deliver 6.5-Mips performance at 3 V. With a maximum operating frequency of 50 MHz, the devices target controller apps in digital consumer and office automation products.

Pawlowicz said Hitachi is developing still more 32-bit MCUs for introduction at the end of this year or early 2003. Based on the SH2, they will use Hitachi's 0.18-micron flash process and 300-mm wafers and will carry 256 kbytes, 512 kbytes or 1 Mbyte of flash memory on-chip, using channel hot electron technology to write to f lash. Write time is said to be 2.5 seconds.

The devices will operate at 80 MHz and target automotive and electric motor control.

— Anthony Cataldo and David Lammers contributed to this story.