Vincent ChuffartEnsuring interoperability between components, boards and systems without some sort of modification has been an ongoing challenge for virtually all embedded systems designers, and was a factor in stifling the market potential for the powerful new VPX standard. There are many different specifications for VPX-based modules that did not have a framework for interoperability resulting in a multitude of design options. The wide breadth of design options from multiple vendors did not, however, serve to advance VPX-based standard product adoption. This scenario is not new to open architectures that require multi-vendor participation for adoption. So, with obvious gaps in the architectural framework, the OpenVPX working group has established a viable and workable solution that has kept the high performance advantages of the VPX specification.

The OpenVPX System specification describes the technical implementation details for 3U and 6U VPX payload and switch modules, backplane topologies, and chassis products. The primary objective of the new open specification is to provide clear and understandable design guidance with specific details engineers can apply on how to build interoperable computing and communication platforms.

A Healthy Ecosystem
Technology suppliers and embedded systems companies both realize that for OpenVPX to thrive, it requires more than a selection of VPX standard cards or single board computers (SBCs). A healthy ecosystem of interoperable components and systems is needed. It is critical that this ecosystem include laboratory equipment in the form of transition modules and small rack systems that designers can use to reduce development time and provide the platform to test applications. Also important is the availability of deployable enclosures, backplanes and fully qualified turn-key computers.
The OpenVPX specification allows OEMs to tap into currently-used I/O ecosystems with PMC and XMC carriers that fit into the backplane to support existing I/O mezzanines. And because VPX specifies the connector interface and does not introduce a new bus structure, designers can re-use existing device driver software and run the operating system unmodified on VPX-based systems.

Healthy Ecosystem
OpenVPX ensures that a healthy ecosystem is available to support widespread adoption of VPX
With a viable ecosystem in place, embedded designers can realize the benefits of reuse, a greater selection of state-of-the art components, faster time-to-market and lower risk technology options that help them deliver application-proven standardized products.

OpenVPX Puts VPX to Work
New high performance, compute-intensive military applications such as radar, sonar, and imaging systems on airborne fighters or video surveillance systems on unmanned aerial vehicles (UAVs) require the highest processing speeds and widest I/O bandwidth. With firmly delineated interoperability points specified in OpenVPX, an ecosystem of VPX-based software, boards and fully integrated systems is ready for broad adoption to satisfy next-generation military system needs. Designed to enable high frequency signals, the VPX backplane supports the latest networking and interfaces including 10 Gigabit Ethernet (GbE), the PCIexpress fabric and Serial ATA (SATA). An example of new capabilities achieved from VPX would be that a system that supports 10 GbE can handle a fast data rate and transmit it in parallel to multiple processors to efficiently manage the workload.

OpenVPX was designed as a “living” specification by providing specific design profiles that suppliers and integrators can use as design requirements. It keeps innovation alive and puts all technology on an equal playing field by reviewing all proposed architectures, regardless of source. There is also a mechanism in place to support higher backplane signal speeds as technology advances and matures as well as one that can retire architectures that have no product support.

To help simplify the design process and allow designers to integrate a variety of different VPX modules, backplanes and chassis depending upon system requirements, there are four types of profiles defined by the OpenVPX specification. These profiles include those for the slot, module, backplane and chassis. In a logical order to ensure interoperability, OpenVPX defines the slot profile first with a definition of the physical mapping of the ports onto a given slot’s backplane connectors with properties for the type, number and size of user-defined pins and planes. Furthermore, the backplane profile defines backplane implementation with details on the number and type of slots and the topologies used to interconnect them. The profiles for the chassis include mechanical, physical dimension, cooling and input power specifications. The definition for the module profile provides physical mapping of ports onto a specific module’s backplane, and the operating compatibility between modules and slots and between multiple modules within the chassis.

Profiles set the stage for a defined interoperability framework between OpenVPX-based products with the help of specifications for planes, pipes and cooling methodologies. In addition, with defined backplane lengths between one to twenty one slots in a variety of backplane styles that include central switch, root-leaf and distributed topologies, OpenVPX covers a broad spectrum of application requirements. All is designed to facilitate the process of system integration to nurture and expand the VPX ecosystem.

Military systems designers can capitalize on the power of the 3U and 6U VPX backplane infrastructure to develop high performance embedded computing applications using standard technologies such as Linux or RTOS on x86 and TCP/IP, which also offer future scalability. Because VPX-based boards offer a rich collection of I/Os included for each node, applications such as rugged multi-display consoles have the performance and bandwidth supplied by two independent Single Board Computers (SBCs) in a single 3U or 6U VPX slot. The flexibility provided by the I/O allows the potential to run a different operating system on each processor.

Ready for Adoption
The ratification of the OpenVPX, VITA 65 specification enables designers of high performance embedded systems to have a working platform that will allow widespread adoption of the powerful VPX standard. With OpenVPX defining important interoperability guidelines and continued advancements in computing density and performance, the mandates for standardized rugged COTS solutions can be satisfied with viable a ecosystem of fully deployable, compact VPX-based products.