Headlines

Headlines

Implementing the Intel® Atom™ Processor Series on the Intel® ECX Form Factor

By Frank Shen, Product Marketing Director, American Portwell Technology Inc.

In an industry where thinking small is the default mindset, embedded-systems boards (ESBs) for use in compact and fanless applications are on the rise. Examples of such applications include portable medical-imaging devices and in-vehicle infotainment systems.

Figure: This picture shows one of the first Intel® Atom™ processor-based in-vehicle infotainment systems - a compact car PC that fits in a single-DIN space.

Benefits of the Intel® Embedded Compact Extended Form Factor (Intel® ECX Form Factor) single-board computer (SBC) are well known (see “Intel® ECX Form Factor Provides Cost and Space-Saving Solutions,” http://www.embeddedintel.com/ search_results.php?results=138). Its compact size of only 102 x 146 mm provides a small footprint. But what components will complement this small size? This was the problem that faced designers at Portwell. For example, the processor would need to be small; that was a given. In addition, it would need to be low power. If the final product was to be the logical next step in the company’s family of ESBs for applications like car PCs, it also would need to be fanless while supporting single and dual display and operating under extreme temperatures. Based on these criteria, the new, 45nm, ultra-low-power, single-form-factor Intel® Atom™ processor and its paired control chip appeared to be a good candidate. Its features include the following:

  • It represented the latest manufacturing technology.
  • Its combined CPU and System Controller Hub (SCH) consumed less than 5 W.
  • The CPU measured a mere 13 x 14 mm and the SCH was only 22 square mm.
  • It supported dual display, audio, USB, and SDIO.
  • It boasted a 400-/533-MHz FSB speed with a 32-bit address.
  • It had an integrated 3D graphics core.
  • It supported single, clone, and dual-independent video modes.

To meet all of specifications, however, the resulting product would definitely increase the engineering requirement for high-density-interconnect (HDI) technology. This fact invited concerns about higher-complexity design processes and subsequent increases in the learning curve, performance-qualification tests, and production yields—as well as subsequent fears of increased product costs. Plus, the designers would need to work with a vendor that was capable of manufacturing HDI printedcircuit boards (PCBs).

Before starting the project, a list of engineering efforts that would be key to design, development, and manufacturing was created:

  • Easy migration from small to large Intel Atom processor package
  • Placement and layout for high density
  • Versatile video interfaces
  • Power management
  • Optimized manufacturing

Defining the objectives if a good start, but doesn’t guarantee a successful outcome. Designing and manufacturing a device based on HDI technology remains a major challenge. But it was just one of many.

Starting Small With Room For Growth

The Intel Atom processor is configured in two package sizes: small and large. The small package accommodates operation in the commercial/regular temperature range of 0 to 40 degrees C. The large package supports the industrial/extended temperature range of -40 to +85 degrees C, but will not be available until late 2008.

The two packages differ in CPU and SCH size as well as ball pitch. Both packages consist of a paired CPU and SCH, which also became a challenge to its implementation. While the large package wouldn’t require an HDI PCB, the small package utilized an HDI ball grid array (BGA). It therefore made high-density technology essential. One of the key design considerations was to design a board that would accommodate the small package while leaving room to migrate to the large package when it became available. Optimizing the placement and layout to reserve this space (without changing the size of the Intel ECX form factor) for the large package can make the eventual migration to the bigger processor faster and easier.

Advanced Placement And Routing

The next step was to find a PCB supplier that could provide an HDI product. Natually, the board design and layout process had to ensure optimal placement of the components within the confines of the Intel ECX form factor. The compact form factor of the Intel Atom processor small package came with the following: 441 pins and 0.5992 solder ball pitch on the CPU and 1249 pins and 0.5927 solder ball pitch on the SCH. Because this ultrasmall package had less room to route, placement and layout were serious issues. The critical engineering considerations that arose from working in such a confined space were: how to optimize location for each component, how to eliminate signal interference, and how to stabilize the trace connection between PCB layers.

Once the placement process was completed, the designers turned their attention to the layout of the circuitry on the PCB. They could then optimize the connections and ensure maximum performance from the board. One of the many issues for layout routing on an HDI PCB is the potential for higher interference. After all, maintaining the optimum signal condition between trace and trace and layer and layer is much more difficult – doable, but difficult.

Putting Customers In The Picture

Video is one of the important features in our customers’ applications. The Intel Atom processor was particularly suitable for this project because it was already designed to support single-, clone-, or dual-display video output. Yet work was still required to meet all of the design specifications. In addition to the LVDS video interface on board, two additional video interfaces needed to be available to increase flexibility: VGA and DVI.

Video is one of the important features in our customers’ applications. The Intel Atom processor was particularly suitable for this project because it was already designed to support single-, clone-, or dual-display video output. Yet work was still required to meet all of the design specifications. In addition to the LVDS video interface on board, two additional video interfaces needed to be available to increase flexibility: VGA and DVI.

Powering Up The Atom

The Intel Atom processor’s paired control chip is a departure from previous Intel® chipsets,, which incorporate the power plane needed by the CPU. In prior chipsets, the south bridge usually supplies the power sequence for the second control chip and CPU. The Intel Atom processor breaks with that convention and doesn’t include these signals. Its architecture consists of a CPU and a single chip—the system controller hub (SCH)—which doesn’t power the CPU.

To generate the voltage that’s necessary for the processor’s required timing, a power-plane and power-sequence solution needs to be in place. This meant that an independent power-plane management solution was necessary to fire up the processor. Engineering this power-plane management without taking up a lot of space posed an initial challenge. An embedded controller (EC) was finally selected to handle power-plane management and boot up the Intel Atom processor.

The EC provided the minimum functionality that was required. At the same time, it provided thermal management and an advanced-configuration-and-power-interface (ACPI) host interface. That interface defines common interfaces for hardware recognition, motherboard, device configuration, and power management. The EC also provided a serial-peripheral-interface (SPI) bus interface. This microprocessor solution booted up the CPU and SCH while enabling the designers to maintain its spacesaving and cost-effective design.

Making The SMT Smarter

In addition to circuit design, placement, and layout, manufacturing is the final key engineering effort that’s needed to ensure the success of any product. Due to the high-density-interconnect technology, more detailed processes were implemented in the surface-mount-technology (SMT) operation. The optimized process needs to assemble the board, meet Portwell’s quality standard, and remain within our economic scale. Our production engineers responded to this requirement by fine-tuning their approach in order to augment the process. They managed to reduce production time while still maintaining an effective yield rate. Since completing the project early this year, the PEB-2736 has morphed into the PCS-8230—the first Intel Atom processorbased in-vehicle infotainment system (see Figure). It’s a compact car PC that fits in a single-DIN space.

Frank Shen is the product marketing director at American Portwell Technology, where he is responsible for product management and new market development. Shen has over 15 years of product marketing experience in embedded computing, industrial computing, and touch panel industries. He holds a master’s degree in electrical engineering from University of Southern California.