Small Form Factor Developments

Small but Mighty: Small Form Factors Gaining Ground

Embedded applications such as industrial automation and medical are seeing rise in small but powerful designs.


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Application-specific technology and expertise are critical to any embedded design. Advantages such as 45nm technology are pervasive and long-term, impacting embedded architectures across the board—whether designing for airline in-flight entertainment, transportation or telecommunications. Better graphics, greater security features and much more result from greater performance per watt and less physical space required for the design. Understanding small form factor options and their accompanying performance benefits is one of the most valuable weapons in a designer’s arsenal, especially in tandem with in-depth industry-specifics that make all the difference.

The days of setting standards single-handedly are over—and non-proprietary form factors are set to play a significant role in the development of these embedded computer systems for vertical applications that are characterized by long-term availability and robustness. Industry standard form factors and compliant products have become something that suppliers simply have to offer.

Significantly more decisive is service and support, from the choice of form factor to after-sales service and technical support, as well as the right solutions for customers’ applications, taking into consideration the particular industry and necessary certification. This is true for all markets. For example, the medical sector is calling for its own standards for medical equipment including traceability and certified manufacturers. Other sectors such as transportation, automation, energy and the military each have other, individual regulatory standards. Based on all these factors, the generic portfolio of embedded computer manufacturers is increasingly concentrating on these vertical markets and offering dedicated design and certification services.

Ultimately, being well-versed in existing, new and evolving small form factors—along with the performance benefits and limitations they each bring to the table—and tapping the deep expertise of a manufacturing partner relationship, are the ways for designers to best understand the alternatives available to them in meeting the performance standards of any particular embedded application (Table 1).

A Growing List of Applications

For example, development of embedded technologies for industrial automation is being driven by several key trends. Probably most important is the impact of space and energy savings achieved through Intel Atom 45nm architectures, enabling a vast new generation of cost-effective, energy-saving, high-performance industrial control solutions. Smaller controllers and platforms are in turn accelerating the trend of industrial Ethernet for connecting smaller PLCs that traditionally used field bus protocols. Using Ethernet as a central communication system improves overall performance and interoperability by enabling devices from different manufacturers to communicate on the same network.

The industrial automation market is also shifting toward vendors that can provide not only boards, but also design, engineering and manufacturing services, as well as a partner network allowing for off-the-shelf and customized, all-in-one solutions. And finally, the introduction of safety-related systems in accordance with the IEC61508 norm—a required standard by the end of 2009—will have a heavy impact. OEMs will need to add safety products to their portfolio, and the market for safety PLCs will grow rapidly.

Medical design is following a very similar path, with the sector experiencing steady growth based significantly on the trend toward ultra-portable medical devices. These tiny devices are improving data collection, speeding up diagnostic capabilities and genuinely enhancing medical care. With new technologies such as 45nm and value-added power management, applications that previously faced barriers due to size, performance issues or power consumption limitations can now be developed using a standard COM implementation—an excellent small form factor example of today’s performance and function. 

PC/104—Sufficiently Simple

In embedded applications where very low cost, small footprint and moderate performance are among the main criteria, PC/104 and PC/104-compatible modules tend to be the norm. With little or no customization, these off-the-shelf solutions prove more than sufficient for a wide range of implementations. With a CPU board and optional peripheral boards stacked together, PC/104 negates the need for a motherboard, backplane or card cage. Fitted with stack-through connectors, these pin- and socket-bus connectors provide a reliable signal path even in harsh environments.

Bus specifications for PC/104 are identical to those of ISA with the exception that PC/104 reduces the drive requirement for most signals to 4 mA of sink current, reducing overall power requirements and allowing ASIC devices to directly drive most bus signals without the need for separate driver components. PC/104’s stability as a form factor and wide availability from nearly 75 vendors, make it an attractive option where simplicity is key and optimum performance is not required.

3U CompactPCI—Rugged and Upgradeable

Legacy issues inherent to many embedded designs can be addressed with 3U implementations of the established CompactPCI architecture (Figure 1). New features meet more harsh computing environment requirements. Many designers turn to 3U CompactPCI, which has much higher bandwidth, Gigabit Ethernet capabilities and more powerful rear I/O over alternative form factors. Unlike PC/104 and MicroTCA, 3U CompactPCI has rear I/O, and can be air- or conduction-cooled. It’s also inherently stiffer than its own 6U counterpart, meaning it meets more rugged standards and is less vulnerable to shock and vibration.

3U CompactPCI is very widely supported and there is a broad range of rugged chassis available for this form factor. And, if an older embedded system is already using CompactPCI, upgrades to the latest processors make an ideal replacement rather than migrating to a new form factor. Compute-intensive applications such as industrial control or airline in-flight entertainment are using 3U CompactPCI very effectively to meet performance requirements in rugged or harsh environments.

Computer-on-Modules – Functionality in a Host of Sizes

For more complex applications, embedded designers should consider computer-on-modules or COMs. COMs encapsulate an entire computer host-complex on a small form factor module which is then mounted onto carrier boards containing application-specific I/O and power circuitry. These off-the-shelf compact modules readily contain all generic PC functions, from graphics, Ethernet, sound, COM and USB ports, to other system buses. The custom designed carrier board complements the COM with additional functionality required for the specific application, for example, medical imaging or capturing patient data such as blood pressure or heart rate.

COMs have been standardized through the Embedded Technology eXtended (more commonly referred to as ETX) standard, enabling full PC functionality, minimum engineering and adoption cost, reliable connectors, slim design, and straightforward upgradability and scalability. ETX modules are highly integrated and compact (95 mm x 114 mm, 12 mm thick) COMs. The standardized form factor and connector layout that carry a specific set of signals—found in all ETX modules—gives designers the ability to create a single-system baseboard that will accept current and future ETX modules. The ability to build a system on a single baseboard using the COM as one plug-in component simplifies packaging, eliminating cabling, and significantly reducing system-level cost—key issues in embedded design.

ETX has further evolved, with improvements to scalability and performance. The newer ETX 3.0 specification offers the same benefits of the original ETX standard, but also adds in 2x Serial ATA with no change in ETX pins, making new modules 100 percent pin-to-pin compatible with previous versions to ensure long-term support. Evolution continues with COM Express and its specifications that satisfy the higher performance market segments of embedded computing and illustrate the trend toward size reduction and mobility (Figure 2).

COMs are ideal for designs needing a great deal of application-specific customization and can accommodate a two-board solution (module plus custom carrier board). Well-suited to a high run of product and the need for some scalability from generation to generation, COMs are perfect for devices or applications that not only require scalability from generation to generation, but also within a single generation. Customizations designed into COMs’ accompanying carrier board can last generations with various CPU cores, for example, swapping out one for the next. 

MicroTCA – Powerful Communication

When communication and bandwidth requirements go beyond the limits of these established technologies, MicroTCA can ante up with very high communication bandwidth, high availability and overall increased computing power in a small form factor. At the larger end of the small form factor realm, MicroTCA can be ideal for high-bandwidth data communications applications such as image processing. Designers who understand its benefits will have another powerful solution to tap for the right design and end-use application.

Up to 12 compute blades on a single backplane—all of which could potentially use a multicore processor—are directly responsible for MicroTCA’s high bandwidth for both communications and computing (Figure 3). A 3U or 4U system, for example, could have as many as 24 cores designed into MicroTCA’s very small footprint. MicroTCA designs can tap as many as 21 high-speed serial connections on the backplane, resulting in bandwidth of 2.5 gigabits per second for each connection. Depending on how the system is implemented, a broad range of communications bandwidth capacities is possible, ranging from 40 Gbits/s to > 1 Tbit/s.

Advances in multicore processing platforms have proven to offer higher compute performance, reduced chip count and lower bill of materials costs with drastically reduced power consumption. As technology shrinks and more real-estate becomes available on the die, chipmakers will continue to push for greater performance, using a combination of improvements in circuitry and more advanced manufacturing technologies. Intel is looking to its next-generation 32nm multicore processors to outpace demands well into the future.

In addition to the multicore trend, the level of integration is another important factor affecting embedded computing technology. This currently has the largest impact on the smallest form factors. Now that integration into the chipsets has taken place, the chipsets are being integrated into System-on-Chips (SoCs) as wafers continue to undergo increased integration and are currently available in 45nm and shortly in 32nm. Manufacturers are now in a position to develop, for instance, credit-card-sized computer-on-modules (COMs) that contain the latest processors in an even more energy-saving design.

Some of today’s most challenging and broad ranging design requirements are found in embedded applications. New technologies can be difficult to adopt and develop quickly, and as a result embedded markets frequently demand reliance on existing or legacy technology for speed and execution of a given design. On the other hand, new applications can be so demanding and communication-centric, they require more performance than earlier architectures have been able to deliver within a small footprint. Wherever the application demands fall in terms of performance, designers must also consider issues of size, cost, scalability and upgradeability, all critical to the overall performance of embedded applications and their imprint on the embedded landscape.

Today, “manufacturers as engineering resources” are even more integral to the design process.  Understanding not only the technical requirements involved in design, but also trends, industry influences, customer requirements and regulatory demands as design elements, make the manufacturer-designer relationship critical to time-to-market and the overall success of the design.

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