Eternally yours at 8 bits

Ubiquitous 8-bit microcontrollers live on in a market that won't die

By Stephen Lawton, illustration by Ben Fishman

It is said that the more things change, the more they stay the same. In the world of the 8-bit microcontroller, this truism drives a multi-billion-dollar market.

Way back in 1980 Intel Corp., Santa Clara, CA, invented the progenitor of the species, the 8051. Today, the technology originally used in such 8-bit microprocessors as Intel's 8086 and Zilog Inc.'s Z-80 lives on in microcontrollers found virtually everywhere.

In fact, look around your office or home, and you'll see plenty of applications of these chips (see "At home with MCUs," below). These 8-bit microcontroller units (MCUs) are in everything from giveaway toys from the local fast-food restaurant to the space shuttle. The $70,000 BMW 745i premium luxury sedan has nearly five dozen 8-bit MCUs, not to mention another dozen or so 32- and 16-bit MCUs that manage key motor and transmission functions.

This is a market that may never die. Ever since Intel launched the 8051, the 8-bit MCU segment has blossomed and continues to this day to reinvent itself and garner new applications.

Worldwide wonder

The 8-bit MCU has become the cornerstone of the embedded market. For products, or applications within a product that have relatively simple, specific processing needs, the 8-bit MCU is often the chip of choice for design engineers. The reason is simple: It's cheap-costing from 60 cents to $2.50 per unit in volume-and it contains an entire computer's primary functions on one chip. The 8-bit MCU can handle anywhere from four to more than 60 I/O channels as well as memory, peripherals, timers, analog-to-digital converters and other functions. This little wonder has enabled consumer and industrial product manufacturers to build goods that might never have seen the light of the marketplace had they depended on microprocessors, external memory chips and all of the requisite support chips.

Worldwide 8-bit MCU sales were about $5.5 billion last year, more than half of the total worldwide MCU revenue of $10.9 billion, according to Tom Starnes, chief analyst for microprocessors, microcontrollers and digital signal processors at Gartner Dataquest Inc., Austin, TX. Microcontroller revenue is down 27% from 2000, he says, due to the weakness in the technology sector and economy as a whole. This year sales will be flat, but Starnes projects that as the economy rebounds MCUs will once again reach their 2000 levels, probably in 2003 or 2004.

Dominating the 8-bit segment is Motorola Inc., Schaumburg, IL, which garners 23% of the market. The company with the second highest market share, Hitachi Ltd., has only 9%. Then come NEC Corp., Microchip Technology Inc., Mitsubishi and STMicroelectronics NV , according to Dataquest (see table, below). As a group, these companies represent 50% to 60% of the MCU market, Starnes says. Some 40 other companies fill out the rest of the MCU market.

What makes 8-bit MCUs so versatile is their low cost and, well, their eight bits, says Dave Yeskey, a vice president at Chandler, AZ-based Microchip Technology. "Most [design engineers] are used to dealing with 1-byte words," he says. A single byte (eight bits) of data is "more than adequate" for handling functions that are not time-sensitive, he notes.

To infinity, and beyond

That doesn't mean they can't be used in real-time situations as well. In fact, when 77-year-old former senator John Glenn became the oldest U.S. astronaut during his 1998 Shuttle Discovery mission, he wore a monitor, powered by a Microchip 8-bit MCU, which tracked his body temperature. That 8-bit MCU sells for about $1, according to Norbert Ohlenbusch, a systems architect at Personal Electronics Devices (PED) Inc., Wellesley, MA, which made the monitor.

Back on earth, Meade Instruments Corp., Irvine, CA, uses multiple 8-bit MCU slaves connected to a master 8-bit MCU in its consumer telescopes to perform such tasks as moving the telescope and maintaining the proper focus. Using multiple MCUs lowers the risk of product failure, because each processor is responsible for just a few functions. Units that use a single, high-end MCU to manage all functions would be prone to more errors, says Ken Baun, Meade's senior vice president of engineering. The 8-bit devices also save room because they fit in what otherwise might be unused space. A single, multifunction microprocessor or larger MCU would require a large motherboard, making the product larger, possibly more expensive and likely less reliable, he notes.

"We don't need to keep lots of components in stock. Sometimes we use exactly the same [MCUs] with slight program modifications" in different telescopes.
-Ken Baun, senior vice president of engineering, Meade Instruments Corp.

Meade could have used a more powerful MCU to determine a planet's position in the sky in real time, Baun says, but instead the company opted for a smaller MCU and a list of precalculated tables. Instead of the MCU constantly calculating the exact position of the planet in the sky, the user sets his latitude and longitude, then the telescope's electronics query a set of look-up tables to determine the correct position in the sky, a function well suited to the MCU, Baun says.

The MCUs in Meade's telescopes cost from $.80 to $3.50, says Baun. Meade's low-end scopes use only one MCU; the high end has as many as 10.

The big capability yet small size of 8-bit MCUs also appealed to Food Automation-Service Techniques Inc. (FAST), Stratford, CT. The maker of commercial kitchen appliances embeds 8-bit chips into its networked kitchen appliances, says Mario Ceste, vice president of business development. One appliance, for example, signals when a burger is nearing tasty perfection and automatically turns on the bun warmer.

While the cornucopia of consumer applications for 8-bit processors continues to abound, automotive and industrial applications still account for the lion's share of installed MCUs, says Dataquest's Starnes. Although consumer products like VCRs ship in the millions, they typically have only one or two MCUs. But cars, which also ship in the millions, have dozens of MCUs. For this reason, Starnes expects automotive and other industrial applications to continue to be the mainstay of the MCU market.

Simple, yet flashy

Today, MCUs range from one-third the size of a dime, a mere 3mm square, to the size of a quarter. Some contain roughly the same number of components in a single device as 20 chips 23 years ago, when the Zilog Z-80 was king of the CP/M-based desktop computer, says Geoff Lees, marketing director for the microcontroller business line at Philips Electronics North America Corp., Sunnyvale, CA.

One trend driving the 8-bit market is the replacement of mask ROM with flash memory. Because it is rewriteable, flash allows manufacturers to program the devices right before they ship, Lees says. This means that code bugs found late in the manufacturing stage can be fixed without wasting chips.

It's like having field-programmable gate arrays (FPGAs) in every product, says Meade's Baun. If the company wants to change code at the last minute or have products that can be upgraded in the field, it can use MCUs with flash. While flash is about 20% more expensive than mask ROM, it saves money at the back end in fewer faulty chips, he says. If a software bug is discovered in an MCU with one-time programmable (OTP) memory or mask ROM, then all the chips already manufactured become trash, notes Kevin Killbane, strategic marketing manager in Motorola's 8/16-Bit Microcontroller Division.

Flash also speeds a product's time to market, he adds. The flexibility of flash MCUs means that customers often do not need to create custom chips, and therefore do not face non-recurring engineering expenses that often come with custom silicon, he adds.

Same song, second verse

An important benefit for system designers is that they can create the parts they need by reprogramming the flash of a single MCU model, says Baun. "We don't need to keep lots of components in stock," he says. "Sometimes we use exactly the same [MCUs] with slight program modifications" in different telescopes.

"We put cost where the feature is," he says. The EXT90 telescope, an entry-level telescope that sells for $150 in stores like Costco Warehouse Corp., uses the same MCU as other, more expensive units. When a user buys a telescope with more features, more capabilities are added to the microcontrollers' flash.



"What makes 8-bit MCUs so versatile is their low cost and, well, their eight bits."

-Dave Yeskey, vice president, Microchip Technology Inc.


These simple MCUs also are getting faster. While early 8-bit MCUs were built to support only 5- to 10-MHz frequencies, some of today's chips can reach a whopping 100 MHz, says Max Baron, a principal analyst at In-Stat/MDR, a market research firm in Scottsdale, AZ, which is owned by ELECTRONIC BUSINESS ' parent company, Reed Business Information. Baron agrees that MCUs today "essentially function as FPGAs," but are more flexible. The programmability of gate arrays is limited, he notes, while MCUs are not only programmable, but can include other functions such as analog-to-digital conversion.

So what does the crystal ball hold in store for 8-bit MCUs? Future chips will offer better performance, more flash memory and require less power, which means the chips will find more uses in handheld devices, mobile electronics and the like, says Lees. As manufacturers move to smaller designs, Microchip plans to move to 0.35 micron and below, says Yeskey. When it comes to next-generation applications, 8-bit MCU vendors "are the glue that holds it all together," he says. "That's the dichotomy of the industry."

While applications for MCUs might change as new features are added, Lees says at least one aspect of 8-bit technology will remain the same: They will always be cheap and easy to work with.

Stephen Lawton, a freelance writer in San Bruno, CA, is the former editor-in-chief of MicroTimes, Digital News & Review, NetscapeWorld and SunWorld. E-mail him at lawton@afab.com.