Hybrid Multi-Monitor Solutions Target Embedded Applications

Display support is extended on next-generation Intel® Atom™ processor platforms.

By Todd Shaner, DFI-ITOX

Many of today’s embedded markets, such as digital signage, capitalize on the availability of large, low-cost, flat-screen liquid-crystal displays (LCDs). In these applications, it’s common to see three or more displays—each with independent imaging. The actual system computing power required in many of these applications is relatively low—except for video image processing. In the past, this function required the use of costly, high-performance mobile, desktop, or even server platforms. The low-power Intel® Atom™ processor platform provides a more cost-effective solution for these markets. But this platform is limited in its ability to support multiple or large-screen displays in these applications. Now, hybrid multi-monitor solutions are becoming available for Intel Atom processor platforms in applications requiring high-definition (HD) 1080p video or more than two independent displays.

Demand For A Hybrid Solution

In second-generation Intel Atom processor-based lowpower “netbook” and desktop “nettop” platforms, the memory-controller hub and Intel® Graphics Media Accelerator (Intel® GMA) graphics core are relocated from the North Bridge to the processor die. In doing so, they provide a board-space reduction. This two-chip design approach also provides lower power with the same performance on the Intel Atom processor N450. In fact, it offers even more performance with slightly higher power using the Intel Atom processor D410 and Intel Atom processor D510. Both the first- and second-generation Intel Atomprocessors use Hi-K technology. To maintain the target thermal design power (TDP) while improving performance, some tradeoffs were required. One of these tradeoffs is the elimination of the serial-digital-video-out (SDVO) display interface from the Intel GMA and new platform-controller-hub (PCH) architecture. The SDVO display port is generally used to implement a digital visual interface (DVI) or high-definition multimedia-interface (HDMI) display interface.

With the elimination of the SDVO port, it becomes challenging to provide cost-effective DVI and HDMI display support on these second-generation low-power platforms. It is possible to implement the required display interfaces using an external graphics adapter. But availability and support issues make this a costly option for embedded applications. In addition, the simultaneous use of external PCI or PCI Express graphics adapters along with the integrated Intel GMA display ports must be carefully tested and validated for each specific application. This is due to interoperability issues with the target BIOS, drivers, and operating system (OS), which are difficult to predict. Intel is working on providing better support for hybrid multi-monitor applications (see references 1 & 2), but many legacy issues are still with us today. By better understanding these interdependencies, it’s possible to design a system that will function properly while opening the door to lower-cost display solutions for the new low-power Intel Atom processor-based platforms. In addition, applications requiring Blu-ray 1080p video playback and support for more than two independent displays can be cost effectively accommodated.

Issues That Must Be Managed

The following is a requirements Q&A checklist for implementation, validation, and methodology to ensure proper platform stability and availability over the required product lifecycle:

1. Are any BIOS changes required and why? The recommended Intel® video BIOS operation disables the Intel GMA display ports when an external graphics adapter is detected at system boot-up. This is done to ensure platform stability over the widest possible range of system applications due to the interoperability issues discussed previously. Because the designer will be taking extra steps to guarantee stability in the target embedded application, this BIOS code can be safely modified.

2. What display port may be used for the primary boot display? If the integrated display ports are to be used simultaneously with an external graphics adapter, an Intel GMA-based display port must be dedicated as the primary boot display.

3. What OS support is required? The target operating system must be supported by the Intel® Embedded Graphics Drivers (currently 10.3.1) and all of the graphics drivers that are required for external graphics adapters. Both the third-party devices implemented at the chip level and all connected hardware devices must have compatible drivers available for the target OS.

4. What if some device drivers aren’t available from the manufacturer for the target OS? This issue is most often encountered with Linux OS applications and when supporting a discontinued OS. The designer’s first resources are the OS user groups and forums, where it may be possible to find a compatible device driver that has already been written for the target OS. These are generally available in the public domain for free use—yet without any guarantee that they’ll provide stable operation in the application. If a project has sufficient time and funding, the designer can develop his or her own device driver(s) internally or contract an outside developer. The resources, time to completion, and risks associated with development of the required device drivers should be reviewed carefully. It may be more cost effective to use an OS that has better driver availability and support.

5. What are the requirements that need to be considered for graphics applications, such as display resolution, DirectX, Direct3D, or other imaging support? DirectX and Direct3D applications that must display in full-screen (non-windowed) mode should be restricted to one display.

6. How does dynamic-video-memory-technology (DVMT) function in an application concerning memory allocation for graphics? System memory is allocated to the graphics subsystem, making it unavailable for use by the application software.

7. What testing must be performed to ensure compatibility and full functionality of the target application? Testing of all hardware configurations with the target OS and application software must be performed to insure stable operation.

8. What types of additional graphics ports are required and do they need to provide simultaneous independent display imaging? This includes standard DVI, HDMI, LVDS, VGA display interfaces and any proprietary display types that must be supported. Use of DVI-I connector type can simplify connectivity for applications requiring both DVI and VGA support.

9. What type of graphics adapters can be utilized? This includes use of PCI, PCI Express, or MxM graphics adapter cards or a graphics processor that’s implemented at the chip level.

10. How does this affect the target application’s mechanical, electrical, and thermal requirements? The available system-enclosure space, cabling system, power-supply capabilities, and cooling provisions should be reviewed to make sure they’re adequate.

To guarantee stability of the final system configuration, a bill-of-materials (BOM) lockdown is required for the revision level of all related hardware, firmware (BIOS), OS, and application software. In addition, all components must be sourced from a manufacturer that supports an embeddedproduct roadmap that meets the designer’s project lifecycle. Selected components that don’t meet long-term requirements can be inventoried for production or purchased at end-oflife (EOL) notification by the manufacturer. It’s important to establish a good working relationship with all suppliers to ensure timely communication of component-revision notifications and changes in product availability.

Application Example

Currently, DFI-ITOX is developing the LR101-B16M Mini- ITX motherboard for embedded applications requiring up to four independent displays (see Figure 1). This standard-formfactor system board uses a flexible design approach that’s configurable with the low-power Intel Atom processor N450, single-core Intel® Atom™ processor D410, and dual-core Intel Atom processor D510. A single-board design (PCB) is used with specific voltage-regulator-module (VRM) components selected at assembly time.

Additional display support is implemented using an S3 Chrome 435 ultra-low-power (ULP) graphics processor. It provides support for 1080p Blu-ray video playback on two independent display ports, which are configurable as 2-DVI or 1-DVI + 1-HDMI. Combined with the integrated Intel® GMA VGA and LVDS display interfaces, up to four independent displays are fully supported. The S3 Chrome 435 ULP graphics processor supports an HDMI interface and provides both VGA and DVI display signaling using two DVI-I connectors (see Figure 2).

COM Express System Applications

The same checklist provided previously may be used to provide extended display support for COM Express-based embedded systems. Additional display support is easily provided at the carrier board level in COM Express applications using PCI, PCI Express, or MxM graphics cards. The most cost-effective implementation is on board at the chip level using a graphics processor. Regardless of the method used, all required components must meet long-term availability and revision-control requirements to guarantee platform stability.

A hybrid multi-monitor-display solution can be implemented on Intel Atom processor platforms to provide support for three or more high-resolution displays through careful component selection, implementation, and validation. Along with thorough system-validation testing, the stabilities of the production systems can be maintained through a BOM lockdown to the revision level of all related hardware, firmware (BIOS), OS, and application software. When any hardware, firmware, or software BOM component requires a revision change, the entire system must be revalidated and verified for proper operation. By following these guidelines, an embedded Intel® architecture system platform with expanded display support can maintain five- to seven-year availability or more.


1. Intel® Embedded Graphics Drivers

2. David Galus & Kirk Blum, Hybrid Multi-monitor Support Intel® Corporation, January 2010

Todd Shaner is the business development manager for ITOX Applied computing located in East Brunswick, NJ. With over 40 years in the computer industry, he has held positions in design engineering and product management, along with his current work in sales and marketing. ITOX is a division of DFI, Inc. based in Taipei, Taiwan. DFI-ITOX is an Associate Member of the Intel® Communications Alliance. Contact info: todds@itox.com 732-390-2815 x6712