Kishan Jainandunsing
(April 2006)

In this column we highlight monthly in a series of articles the value propositions of the COM Express standard. This month’s article is the last one in this series and is about new opportunities COM Express offers add-on card manufacturers in the embedded industry.

COM Express: A Unique Opportunity for Add-on Card Manufacturers

Summary

The ability to instantly add embedded host-computer functionality through industry standard modules gives specialty add-on card manufacturers the ability to design their add-on card products as carrier boards instead and explore new niches in their focus markets.

Dilemmas of the Traditional SBC Approach

Specialty add-on cards for industrial applications can be fairly complex in terms of system dependencies. This complexity expresses itself in terms of system BIOS, or even chipset compatibility issues. Examples of add-on cards where such issues often crop up are high-speed video capture, complex data acquisition and network security add-on cards.

The traditional approach is to use these add-on cards with a SBC (single board computer) that has add-on card expansion slots. See Figure 1. This approach has a couple of shortcomings:

• Only a limited set of SBCs may be recommended. Those, which have been tested for BIOS and chipset compatibility with the add-on card. This may be very restrictive to the customer and the add-on card manufacturer has no control over the supply of these SBCs.
• Interchanging SBC products due to obsolescence or supplier issues can pose compatibility issues with the BIOS, chipset and enclosure, as I/O connector, header and expansion slot positions are not standardized for SBCs.
• Equipment form factors become very restrictive, and typically gravitate towards a “beige” PC/AT box, as this form factor is a prolific standard for PC enclosures.

The above shortcomings further limit the market for an add-on card manufacturer and pose heavy technical support burdens due to incompatibilities with BIOS and chipsets.

If only one had the ability to add the host portion as a standardized module to the add-on card, which is then designed as the main board. That would give the add-on card manufacturer control over BIOS, chipset and connector/header/expansion slot incompatibilities, as well as control over form factors.

Figure 1. The traditional SBC add-on card approach

The COM Express Solution

The PICMG COM Express standard for computer-on-modules allows add-on card manufacturers to do just that. And since COM Express is an open industry standard, adopted by the main suppliers of embedded hardware solutions, there is no fear of committing to a proprietary solution.

Since a COM Express module shields the designer from host design complexities, the add-on card manufacturer is focused only on its own core technology and standard interfaces, such as PCI Express, PCI, Serial ATA (SATA), IDE, USB, etc. And the fact that the COM Express module is an off-the-shelf, tested, known-good and qualified component, the designer does not have to run debugging routines on this part of the design. Figure 2 illustrates this approach.

Although COM Express module manufacturers may use different chipsets and BIOS configurations between products, it is much easier for the add-on card manufacturer to focus qualification on a limited number of COM Express module suppliers than it is with SBC suppliers. This is so, because COM Express modules do not show the same large degree of variations as SBCs.

Figure 2. The COM Express add-on card approach

Specialty add-on card manufacturers can further explore and expand into full system products at the fraction of the total cost involved with an SBC, without the confinements of a commodity PC/AT box form factor. Figure 3 illustrates this concept.

Figure 3. The COM Express add-on card approach for system products

Conclusions

The COM Express standard provides specialty add-on card manufacturers for the first time with the ability to control host and I/O interface incompatibilities, as well as form factors. It also allows these manufacturers to expand their business into integrated system products at very low investments in system product development.

End of Part IV