OpenVPX eases harsh-environment systems integration

With OpenVPX (VITA 65), integrators are choosing interoperable module architectures for next-generation systems. Thus, high-performance embedded processing systems engineers have more reasons than ever to choose a VPX (VITA 46)-based system design. VPX was initiated to address the challenge of enabling high-speed serial interfaces using the multi-gigabit capable RT2 connector family. (And that was the easy part.) And, like any new innovation, VPX has endured its share of growing pains.

Today, however, is a different ballgame. OpenVPX – which specifies VPX system-level interoperability via defined profiles and planes – will soon be ratified, representing a great leap forward in the technical maturity of VPX. Stewart illustrates how OpenVPX simplifies system interconnection via a case study, then explains 1) how OpenVPX furthers VPX’s ecosystem and 2) how VITA initiatives are broadening OpenVPX.

System interconnection made simple: Case study

OpenVPX defines a generic system interconnection architecture for VPX consisting of three primary communications planes – Data, Expansion, and Control. Currently the defined option for OpenVPX Data and Expansion planes are PCI Express and Serial RapidIO, whereas the defined options for the Control plane are various implementations of Ethernet.

To illustrate the concept of the different communication planes, Figure 1 depicts a high-performance video processing subsystem. Such a system could be deployed in a military vehicle to provide immersive visual situational awareness to the vehicle commander. The system diagram illustrates the following uses of the communication planes:

  • The Image Capture module moves data to the Control Processor over the Expansion Plane.
  • The Control Processor moves data to and from the Video Compression and Encryption module over the Expansion Plane.
  • The Control Processor communicates to the High Performance Graphics module over the Data Plane; typically this would be PCI Express to provide the highest performance and most direct connection between the Control Processor CPU and the graphics processor.
  • The Control Processor communicates with other system elements and to external equipment via the Ethernet-based Control Plane.

Figure 1: A conceptual system diagram of a high-performance video processing subsystem, illustrating various usages of the OpenVPX communication planes.
(Click graphic to zoom by 1.9x)

OpenVPX furthers the VPX ecosystem

No longer considered a niche technology, VPX is now mainstream in the military and aerospace industries. The VITA online directory includes nearly 100 OpenVPX-compliant products and indicates/illustrates the introduction of second- and third-generation products in core areas such as SBCs and DSPs. Perhaps the strongest indicator of VPX’s product ecosystem’s maturity is the appearance of specialized supporting products like test backplanes, power load modules, and a cable-terminating connector that enables cabling directly to the backside backplane connectors instead of using a rear transition module.

Ongoing VITA standards broaden OpenVPX

Looking forward, VITA continues the work needed to broaden the scope of its VPX and OpenVPX standards. Numerous initiatives are underway, including:

VITA 62 – The development of a standard power supply module for OpenVPX systems. This will allow system integrators to design a standard power supply slot in their system and choose a power supply from a competitive pool of suppliers. As a comparative measure of maturity, even the venerable VMEbus never included a standard for a power supply module.

VITA 66 – Defines an optical interconnect for use on OpenVPX modules.

VITA 67 – Standardizes RF connectors for use on OpenVPX modules and allowable combinations and positioning of RF connectors and standard connectors. This provides a standards-based approach to route RF signals such as radar or communications signals to the receiver payload module, avoiding front-panel I/O or customized solutions.

OpenVPX readies mil/aerospace market

Equipped with an ongoing arsenal of product announcements, the VPX community, now armed with the new OpenVPX standard for improved interoperability, has never been more ready to build harsh environment, computer-intensive military/aerospace systems.

Stewart Dewar, Product Marketing Manager at General Dynamics Canada, can be reached at