RTC Magazine

ARM-based platforms dominate low-power market segments, especially for smartphones, tablets and HMI subsystems. Welcoming news for embedded designers is that the ARM processor architecture has evolved to support a wider range of interfaces and functionality allowing a true open-systems approach. Because of its performance and low power consumption, the latest ARM technology is now an optimal solution for an increasing number of small embedded form factor applications. OEMs are turning to ARM as an attractive platform for low-profile, high-density embedded devices. Furthermore, today’s suppliers of ARM solutions now have the ability to deliver the needed scalability for efficient development from one generation to the next from a growing ecosystem of providers. Open system, ARM-based solutions are now available offering small size, scalable performance per watt and interface configuration advantages that help meet the design challenges of many tablets, HMI tools and other smart connected devices. 

Satisfying Growing Requirements

In addition to the technology, power and connectivity requirements of current embedded tablet and HMI tool applications, there also is the need to meet rugged requirements including design considerations for shock, vibration and extended temperature conditions as well as support for extended lifecycles. The users of these applications demand that they be lighter, smaller and fully sealed, fanless, portable systems and must maintain 24/7 reliability.  Markets for these and similar applications have been underserved by existing low-power architectures. Although OEMs have made use of currently available technology to address their design needs, most present form factors, specifications and processor architectures are not an optimal, best-fit solution. This is because they are not specifically tuned to support System-on-a-Chip (SoC)-based subsystems.

ARM processors have proven that they are powerful enough to drive an easy-to-use graphical user interface (GUI) for new mobile applications and, at less than 1 watt operating power, they also offer extremely low power consumption. ARM-based solutions combine extended temperature support with dual and quad core CPU performance that is comparable to, and many times exceeds, that of the latest low-power x86 and RISC-based processor product offerings available today. Designers are realizing that different processors offer different advantages allowing them to select the right one for their form, fit and function needs. ARM will not replace x86 or RISC technologies, but is an alternate platform for segments that are currently underserved.

One of its key advantages is that ARM supports long product life—a minimum of seven years and up to 15 years—and it is small in size and height, plus it does not require a chipset. This means the total bill-of-materials (BOM) can be reduced for a more cost-effective and streamlined hardware design. ARM technology eliminates the need for moving parts such as those associated with active cooling, which helps developers to achieve simplified system cooling and thermal management. This helps improve overall system MTBF by reducing points of failure resulting in higher system reliability, and supports a platform for higher density systems. The resulting systems are thus easier to develop and manufacture. Both weight and cost are reduced because there is no need for heat pipes, heat sinks or fans. In addition, the native features and broad range of interfaces supported by ARM technology result in a more all-in-one solution that reduces integration and development time and contributes to shorter time-to-market.

Valuable Application Building Blocks

To date, there have been many ARM solutions available in the market, but most offer limited interoperability and almost none offer a smooth design migration path. ARM-based solutions have typically required more in-depth development because of their proprietary nature with the software directly tied to the hardware and the specific end application. This has made it necessary to virtually start from scratch on any new design. There is a true need for proven design building blocks for connected devices and subsystems such as those being developed for tablet and HMI-based applications. 

The market has lacked solutions and building blocks that enable longevity and smooth migration from generation to generation. Leveraging the benefits of verified open architecture ARM platforms, OEMs can avoid the delay caused by time-consuming hardware validation processes. ARM building blocks need to be implemented as part of a higher level, ultra-low-power solution that includes a combination of an application-specific carrier board, firmware and drivers, and the target operating system. Offering multiple layers that make up a complete ARM solution provides time-to-market development benefits and added value for OEMs. 

The availability of pre-validated platforms that are fully configured and tested to deliver the required interoperability and functionality is important to overall ARM implementation success. Application development, operating system integration and adding middleware can be streamlined because the process of hardware validation on the part of the application designer has been eliminated. With pre-validated building blocks, customers are assured of compatibility, interoperability and high reliability so designers can fully focus on application development rather than dealing with the challenges of hardware integration.

Competition in the tablet and smart connected markets demands that OEMs remain keenly focused on differentiating their products. Time spent on developing or debugging hardware results in less time to concentrate on individual application advantages. With pre-validated solutions that utilize optimized building blocks, OEMs can reuse their existing libraries of application-specific software and install it on a ready framework and flexible hardware.

This is beneficial to OEMs because they will be able to obtain highly scalable platforms with complete board support packages (BSPs) for virtually all popular operating systems. The development options brought about by suitable hardware-specific software enables the creation of increasingly homogeneous application-ready platforms. OEMs will then be able to switch from one board, module or system to another with relative ease. What will make all this a reality is providing appropriate standardization at the board and hardware-specific software levels coupled with the inclusion of extensive software services.

Successful Implementations through Standardization

SoC-based hardware requires a different design approach that addresses a new I/O mix. One approach to satisfying these development needs is leveraging existing standards such as Pico-ITX and mini-ITX as well as developing new modules that can serve as best-fit building blocks for next-generation smart connected devices utilizing ARM technology. Because the Pico-ITX format is standardized, application-specific selection of a suitable x86 or ARM design can take place barrier-free using only a single ecosystem. The advantage is mechanical compatibility achieved within an OEM’s existing product portfolio, which greatly eases system design. Similarly, COMs offer a scalable highly integrated solution that supports system expansion and customization by delivering core functionality allowing application-specific features to be handled with a carrier board. Both are low power consumption small form factors that give designers a choice depending upon the feature set, space constraints and customization required for a given application.

In order to standardize an embedded architecture platform for low power SoC and ARM-based designs, Kontron recently proposed a new Computer-on-Module specification. The proposed specification and products shift the focus to power consumption and performance per watt, and help thin the border lines between different processor technologies, making the software ecosystem expandable to further technology platforms.

Until now, existing module specifications have been heavily influenced by x86 technology, with feature set definitions proving too complex for ARM architecture. As an example, a typical x86 chipset offers a multitude of PC interfaces such as PCI Express lanes, USB and SATA ports. However, ARM SoCs feature more classical embedded ports such as UART, I2C and several SDIOs, with fewer PC interfaces. Applications that utilize PCIe x16 graphics and PCI are not natively supported. ARM-based SoC designs also have differences in video outputs and dedicated camera interfaces. In ARM processors, these are often implemented according to the MIPI standard such as Camera Serial Interface (CSI) and are currently not implemented in a module standard.

The new proposed COM specification has defined two new form factors for embedded module designs. One small module measures 82 mm x 50 mm and a larger one measures 82 mm x 80 mm. The larger COM is primarily intended for future high-performance multicore processors. Both are based on the 314-pin MXM 3.0 connector, which provides a durable and flat construction with a cost-efficient card edge allowing several form factors to be supported and added flexibility regarding various mechanical requirements (Figure 1). Even more decisive is the fact that the pin allocation and thus the feature set are specifically designed for ARM and SoC processor technologies. The new connector enables implementation of new interfaces that include video outputs such as LVDS and embedded DisplayPort. Support for 24-bit RGB and HDMI is also possible. For the first time, dedicated camera interfaces are also included in the specification. Consequently, designers are not constrained to make compromises with inefficient specifications that are stretched between the x86 feature set and lean ARM I/Os.

The first ARM-based products will follow the Pico-ITX standard and be based on the Texas Instruments Sitara AM387x and the NVIDIA Tegra processors. A hardware board-level design demonstrates how the selection of a suitable CPU for an application can be simplified. The interface feature set of Kontron’s NVIDIA SoC-based Pico-ITX board (see sidebar) only varies slightly from that of Intel Atom or AMD Embedded G-Series-based designs—two existing x86-based portfolio offerings. The main variance lies in the processor used, and hence the performance class (Table 1). 

Comparison of the three Pico-ITX boards’ feature sets reveals very few differences in terms of the most relevant interfaces such as USB, Ethernet and graphics and memory for SFF devices. It also demonstrates that the future, scalability and expansion into ARM technology offers a truly viable design resource for embedded OEMs.

In addition, new COM product building blocks are in the final testing phase and are scheduled to be released early in 2012. By extending the COM usage model to RISC architectures with a scalable, modular module standard helps developers bridge the gap, bringing the functionality of consumer market applications to the embedded market with rugged and high-reliability solutions that meet the needs of demanding industrial environments. 

Kontron
Poway, CA.
(888) 294-4558.
www.kontron.com