Distributed processing and new applications are pumping new life into what was until very recently considered dated technology.

The market for 8-bit microcontrollers is booming, but not in the places most analysts and electronics companies anticipated.

In terms of raw dollars, most top-line projections among analyst firms remain relatively flat. Behind those dollars, however, the total numbers of 8-bit microcontrollers shipped and expected to ship continues to grow even as prices continue to fall. Moreover, these devices are finding their way into new markets at the cutting edge of advanced medical devices, automobile electronics and in consumer electronics.

STMicroelectronics, one of the market’s top mega-contestants, estimates the overall 8-bit MCU market at $5 billion, with unit shipments expected to grow 48 percent between 2007 and 2011.Freescale puts the number at $4.5 billion to $4.7 billion, with relatively flat dollar growth until 2011. And Atmel estimates the combined 8- and 16- bit MCU market is worth $11 billion, with plenty of new designs to win.

Still, all of this runs counterintuitive to the overall growth trend in electronics, where the fastest clock speed at the most advanced process node is considered a sign of progress. It has been assumed by most industry watchers that growth in 8-bit MCUs would proliferate in developing markets because they are the least costly and lowest-function devices, but that they would fade away in markets for more advanced electronics. While demand continues to escalate in developing markets, it’s not the real growth center—or the main focus for competition among the top companies fighting for this space.

That may help explain why STMicro just introduced a new 8-bit MCU platform in late February, and why Atmel is spending so much time trumpeting the advantages of its AVR architecture. It also explains why Microchip and Freescale continue to focus so much of their support and development resources for what appears from the outside to be an aging technology.

Aiden Mitchell, product management director for Freescale’s microcontroller solutions group, said the explosive growth in 8-bit is coming from green energy control, medical and gaming—everything from insulin-releasing devices to Wii gaming console controllers. He said those devices require a low cost and proven ability to deliver on function and connectivity, and 8-bit MCUs have a long track record under even the harshest conditions.

“In the bill of materials, it’s primarily about electronics and packaging,” Mitchell said. “And when you get an insulin product for less than $4, the only way you can get to the performance threshold for that cost is with an 8-bit microcontroller.”

For engineers designing these devices, there also is a long list of available peripherals, detailed benchmarked performance and low voltage/low power options. “Many engineers don’t care about the core requirements,” Mitchell said. “It’s how easy it is to design and get up and running and in a format with pin compatibility.”

Increasingly, however, that’s only part of the picture, he noted. “In emerging markets— particularly China and India—the real preference is legacy packaging, which requires us to invest in the technology and maintain supply. But we’re also seeing a big growth in semi-custom designs or SiPs (systems in a package), where the customer may be integrating 8-bit microcontrollers with radio. We’re getting more flexible about how to approach this market and we’re devoting design resources.”

Microchip, meanwhile is seeing growing interest in 8-bit, as well, despite a concerted push at the high end of the microcontroller market. The company attributes the growth to what Terry Schmidt, senior marketing manager for the advanced microcontroller architecture division, says is “engineers being more thoughtful of distributed processing.” He said the ZigBee (short-range wireless standard) stack,MiWi (homegrown Microchip solution) and other smaller stacks are all leveraging more local processing using microcontrollers.

“With low power and very small devices, it’s easier to put an 8-bit processor at the sensor node,” he said. “In applications that are contained, like a cell phone, we’re seeing customers add functionality around the central core with an 8-bit microcontroller. They can do that with better time to market.”

He added that 8-bit microcontrollers are edging back into the mainstream in those areas. While a 32-bit microcontroller will be used in the core processor in a device, 8-bit MCUs play roughly the same role as an extra core in a CPU.

New vs. old
Just how the market breaks down—lessexpensive, older packaging—versus advanced new architectures that provide both higher performance and lower power consumption is anyone’s guess. The market for 8-bit MCUs is possibly one of the most diverse in electronics today, spanning everything from

Size matters
One of the other advantages for 8-bit microcontrollers is their size. They can be designed for spaces far too small for larger CPUs. And in portable devices, where there is a growing need for specific processing functions that require little batter space, MCUs are particularly useful.

The opening of this type of market also provides a new opportunity for MCU vendors, because there are few incumbents in consumer electronics. It simply changes too quickly. And in a market where processors are the costly piece of the equation, adding new functions quickly and cheaply is an attractive option for designers.

variable speed motors and industrial sensors to basic washing machines.

Precisely because of that, it is nearly impossible for any single vendor to tap all of the available markets. While Microchip and Freescale have been extremely successful in this market, both are leveraging a tried and true architecture that has been tweaked about as far as it can go. And both are emphasizing pin compatibility and internally developed tools to provide headroom for engineers looking to design more performance into devices.

Atmel, meanwhile, hasopted for a different approach. Its 8-bit architecture was developed in 1996, which is considered a newcomer in this market. The company claims it is the only architecture developed in the past 15 years to be successful.

“The real advantage here is that you can write code in C,” said IngarFredrikson, product marketing director for Atmel’s AVR. “Many of the older chips also run four clock cycles per instruction, versus six for AVR. That means you can run program and data memory in the same clock cycle. The older architectures also have only one accumulator, and they never imagined you would need more than 64k embedded memory.”

Atmel has been successful in some of the newer white goods, electronic toys, automobile key fobs and mirrors and industrial motor control and control systems.

STMicroelectronics, meanwhile, believes there is enough growth in this side of the market to introduce a new line of microcontrollers, which will begin shipping in the first half of this year. It includes 16-bit index registers and a stack pointer and, like Atmel, allows designers to program in C. The device also boasts a wide voltage range for a variety of applications, ranging from 1.65 volts to 5.5 volts, which puts it on par with Atmel’s AVR line. In contrast, the low-power end of the Microchip and Freescale lines will only scale down to 1.8 volts.

In addition, all of the companies provide tools to program the devices, which may be the best sign yet of just how competitive this market has become.