Advanced Process Nodes Transform MCU Market



Integrated peripherals and sensor capabilities in today’s MCUs support new applications in wearable and ultra-mobile designs.

To get a sense of where innovation is occurring in 8-, 16- and 32-bit microcontrollers, we talked to Jason Tollefson, senior product marketing manager for the MCU16 Division at Microchip Technology Inc.

EECatalog: As the price of 32-bit MCUs falls, the bill-of-material cost penalty for moving to a higher-performance device is disappearing, but what other development costs do engineers still need to weigh as they consider options from 8-bit to 32-bit?

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Jason Tollefson, Microchip: As the price of 32-bit MCUs fall, so do the 8- and 16-bit MCUs. The best approach is to select the appropriate device for the application, rather than a “platform” approach that spans several disparate apps. For the same MCU cost, you can get more peripherals for the same price. Microchip’s peripherals are intelligently interconnected, and can often implement complex functional blocks without intervention or supervision from the core.

The movement to advanced process nodes is fundamentally transforming the MCU market. Lower costs per transistor have ushered in a wave of new high-performance, 32-bit solutions. But this same movement has also lowered the cost of adding more peripherals with greater sophistication. If you consider that the area required for both 8-bit and 32-bit cores are shrinking at the same rate, then using an 8-bit core will still occupy a smaller footprint, even on an advanced process node. This leaves MCU designers with an interesting choice: install an entry-level 32-bit core, or keep the 8-bit and add more sophisticated peripherals.

Customers should evaluate MCUs based upon the needs of their application. If an 8-bit MCU with more sophisticated, autonomous and interconnected peripherals can do the job for less cost, then that is the right answer. If higher computational performance is the key need, then a 32-bit MCU is the right answer so long as it can meet the cost and power consumption needs of the application.

EECatalog: How are the demands of wearable and other small, ultra-mobile devices driving new microcontroller technologies?

Tollefson, Microchip: In almost every case, the primary function of any wearable device is to measure and process data from an environmental input (activity, heart rate, blood oxygen concentration, etc.), log the data in non-volatile memory and periodically transfer the data to another device (usually a smartphone or PC) for correlation and tracking.

Wearable and ultra-mobile devices have a few common characteristics that apply “pressure points” on microcontroller selection. Their small form factor severely limits component area, and imposes strict limits on battery size and capacity. Space constraints also dictate that sensor interface and external analog components be kept to a minimum. As Bluetooth emerges as the wireless interface of choice for the wearable market, so does the requirement to integrate the communication protocol into the system MCU. These characteristics have driven microcontroller manufacturers to create more highly integrated devices that incorporate advanced power management technology, while reducing their physical footprint in x-, y- and z- dimensions.

EECatalog: Where do you expect to see ongoing innovation specifically in 8- and 16-bit microcontrollers?

Tollefson, Microchip: Innovation in 8- and 16-bit microcontrollers is occurring on several fronts, with the primary objective being increased system capability while reducing power consumption, cost and physical footprint. Most embedded systems contain some combination of basic functional building blocks—the most common being power conversion, motor drive, sensor interface and signal generation. Achieving the best efficiency often involves incorporating many of these functional building blocks into as few pieces of silicon as possible.

Savvy embedded designers have long been aware that a more tightly integrated system can reduce power consumption and cost, but have encountered difficulty combining multiple functions onto a single, low-cost MCU. Traditionally, each additional function requires increasing amounts of flash memory to store variables, more RAM to execute code and higher processing speeds to ensure that system timing is within specification. Unfortunately, this method of function integration requires a larger, more expensive microcontroller primarily due to the increased memory requirements. Today’s cost-sensitive embedded design environment requires a move away from the traditional “arms race” of MIPS, bytes and megahertz, and a paradigm shift into the era of function enablement.

Microchip is evolving its 8-and 16-bit microcontrollers to meet this need by incorporating on-chip peripherals that can operate without supervision from the CPU, and have the ability to communicate directly with other peripherals to create flexible feedback loops. These “core independent” blocks of function-specific hardware intelligence require little to no code, consume very little power and are much smaller than the RAM and flash needed to implement a given function within the core processor. This leads to flexible, power-efficient MCU designs with the capability to perform the same tasks as a much larger and more expensive device.

EECatalog: How is the integration of sensors into so many new applications changing your microcontroller product roadmap?

Tollefson, Microchip: Sensors are driving more of the analog signal chain onto the MCU. With the ability to amplify, capture and filter data streaming from sensors, MCUs with analog integration offer lower overall system cost, higher throughput and easier design. All of these traits enable designs to get to market faster, allowing these end products to achieve commercial success in this rapidly growing market.

EECatalog: With respect to wireless connectivity, what are the tradeoffs developers need to consider as they compare single-chip products to multichip modules?

Tollefson, Microchip: As companies develop wireless-enabled products, they are often faced with the decision to select a single-chip solution, or integrate pre-certified modules for their product development. Customers who want to simply add wireless capability to their product features may want to consider pre-certified modules to begin with. While certified modules are typically more expensive than discrete chips, they do offer many advantages. The modules are designed for optimal RF performance, and are typically certified for agency regulations in various countries.

Designing the product by selecting a single-chip solution may appear to be a less expensive endeavor from a material cost standpoint; however, doing so requires proficient RF design expertise, and also involves significant up-front costs for product development and agency certifications. The typical cost of RF engineering is approximately $4K/week, and the certification costs for FCC and other countries can approach $10K per certification. Final product testing also requires specialized RF testing equipment, which will materially increase the cost of goods. If the end equipment does not achieve very high volumes in production, the up-front costs of designing with a single chip solution may not be justified.

So to get in the game quickly, first adopt a module. Once your product is proven as a platform for success, then consider reducing the cost of your application by going to a single-chip solution.


coupe_cherylCheryl Berglund Coupé is managing editor of EECatalog.com. Her articles have appeared in EE Times, Electronic Business, Microsoft Embedded Review and Windows Developer’s Journal and she has developed presentations for the Embedded Systems Conference and ICSPAT. She has held a variety of production, technical marketing and writing positions within technology companies and agencies in the Northwest.

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