EPIC Express paves "bridge to the future"

Where has the year gone?  As 2005 winds to a close, the embedded board market continues to evolve with new technology and products,  and this magazine PC/104 Embedded Solutions continues to evolve with it (more on that later). Of note: the demand for standardized modules has never been hotter as designers search for ways to get to market quicker while avoiding the drudgery and expense of designing an entire system from scratch.  Standardized embedded form factors such as PC/104, PC/104-Plus, PCI-104, and EBX are among the most common types designed into low- to medium-volume systems where small size, desktop PC compatibility, and a robust vendor ecosystem are the primary design criteria.

At huge volumes, systems like automobile telematics, cell phones, PDAs or iPods use proprietary, custom hardware designs. And at the low end, onesy-twosy prototype systems often just use PCs.  The PC/104 family fits perfectly in the middle with its PC functionality, “rich” software portfolio (to use Microsoft’s terminology), and inherent ruggedness that works beautifully in harsh and low-maintenance applications like military or industrial control.

But still the market needs more, so alternative form factors like the PC/104 Consortium’s EPIC standard have achieved success. At 115 mm x 165 mm (4.528” x 6.496”), EPIC is slightly larger than PC/104’s size of 95.89 mm x 90.17 mm (3.775” x 3.550”). EPIC is intentionally designed with space for higher-power processors that can be conductively cooled and have additional I/O connections and the ability to stack legacy PC/104 I/O or processor modules on top.

Vendors including Ampro, VersaLogic, Octagon, WinSystems, Micro/sys, and others all make COTS box-level systems based upon EPIC that are intended make designers’ jobs even easier. EPIC accommodates all standard PC/104 I/O modules, so existing custom interface hardware that drives LCDs, interfaces to ball screw assemblies, or controls thermal ovens can plug right onto an EPIC-based system.

But the PC desktop market is moving beyond PC/104, first by replacing ISA with PCI, and now by moving to PCI Express, a serial fabric that offers orders of magnitude more data movement potential than the PCIbus. This same “gang of five” that created EPIC recently extended the spec to EPIC Express, bringing – you guessed it – PCI Express capability to EPIC. Not since the PC/104 spec was first ratified in 1992 has so much potential been included in a single proposed standard.

EPIC Express retains the stackability of PC/104 by replacing PCI with high speed PCI Express connectors ready for a four-card stack and x1 or x4 lanes. A 2.5 Gbps x1 lane is about 4x the speed of current PC/104 boards, while a x4 lane is about 16x. At these speeds, high end graphics controllers can be mounted on “PC/104 Express” modules (for now called an EPIC Express Module in the specification at www.epic-express.org), along with other high-end data capture, signal processing, or A/D and D/A converters. In short: the EPIC Express CPU basecard and “PC/104 Express” modules perfectly meet the needs of high performance, contemporary small- to medium-volume applications. And because they’re so small, inherently rugged, and flexible, EPIC Express systems have a real potential to steal market share from other standards like 6U VME or 3U CompactPCI.

The EPIC Express creators – Ampro, Micro/sys, Octagon, WinSystems, and VersaLogic – will undoubtedly offer their 0.8 revision spec to the PC/104 Consortium in time for the annual strategic planning session in Q12006. The Consortium would look closely at how EPIC Express addresses the past and the future, as well as how it relates to the existing EPIC specification.  Since PC/104 has been successful for so long partly because of its stability, the EPIC Express gang of five even built in support for legacy ISA-based PC/104 boards.

This means that if the Consortium were to endorse EPIC Express, the existing vendor community’s literally thousands of PC/104 modules could be carried forward, protecting the legacy investments of vendors and customers alike. And looking to the future, besides the obvious support for PCI Express, there is no mechanical reason at all that an EPIC Express module couldn’t be modified to include the popular PMC (PCIbus) or XMC (serial fabric) mezzanine modules used with VME and CompactPCI.  In this case, not only would EPIC Express use its own “PC/104 Express” mezzanine modules, it could use those from other markets and standards as well. What a concept.

I believe the existing EPIC specification and the newer EPIC Express specification represent the future of the PC/104 Consortium – without breaking the fundamental heritage of PC/104. These specs are a bridge to the future that’s increasingly based upon small form factors like PC/104 and others. At PC/104 Embedded Solutions, we’ve watched this small form factor trend evolve for several years now. Accordingly, we’re changing our name in 2006 to PC/104 and Small Form Factors to expand our coverage and bring you timely technical information about new small form factor products and standards. As always, PC/104 remains our core mission and technology.