Your project has a specific set of I/O requirements, but you can’t find a stock board that meets the criteria, and you’re space constrained to a non-expandable case, meaning PCI expansion cards are out. So what do you do? Consider a board with semi-customizable I/O via daughtercards that offer different options for I/O in the upper right quarter of the standard ATX I/O shield:
There are a lot of companies that use such expansion options in fanless barebones, such as DFI’s EC300 series, but VIA, Jetway, and Liantec all offer Mini-ITX boards with customizable I/O so you can use them in whatever case you want. While they all vary in configuration and interface, the idea is the same: Have a pared down set of standard I/O, have the right side be no more than half-height (usually by turning the audio stack so it’s horizontal), and add your own I/O above the half-height section. This yields a tremendous amount of flexibility for embedded applications, while leveraging the cost and time-to-market of commercially available off-the-shelf (COTS) components.
Here at Logic Supply, we’re big fans of the Jetway system, as we feel it offers the best combination of a full-featured motherboard, reasonable cost, and flexible expansion offerings. Need four LAN in a small, relatively inexpensive box? Try the NF96 with an AD3RTLANP in an M350 chassis. Need those NICs to be GbE, or Intel-brand for compatibility? Upgrade to the AD3INLANG. What about a fanless system with automotive ignition sensing and three RS-232 ports to run a custom Linux distro in a road condition monitoring van? NF99 plus AD4COMCB in a GS-L05 with an M3-ATX power supply. Going in a taxi with a credit card reader, receipt printer, and dual displays with a Windows-based application? Swap the NF99 for the NF9D.
All of those systems use standard, off the shelf components that are in stock and half the cost of what you’d pay for a completely customized board. Plus, there are no engineering fees or large minimum order quantities.
The only downside is that if you want video expansion options, you’re limited to the NF92 motherboard; it requires a second set of pins on a separate bus that none of the other boards have. And, because of the package size of socketed CPUs, current products are limited to Atom processors. With the newer 2-chip packages (Arrandale, Sandy Bridge, Ivy Bridge) though, there should be room on the board to add the daughter card interface. Jetway’s Arrandale and Sandy Bridge boards were more multimedia focused than we’d expected; here’s hoping their Ivy Bridge entry will be a little bit different.
Let us know your thoughts in the comments section below.