VMEbus supports 64-bit Core 2 Duo processorsStory
March 20, 2009
Contrary to many industry pundits' gloomy predictions, VMEbus continues to survive and flourish. The simple reason is that it still offers real value, whether this is measured in cost, time, performance, or its unique blend of functionality for many new applications. In addition, it provides the most cost-effective upgrade path for the very large base of existing VME implementations, in both industrial and military systems. VME has managed to maintain backward compatibility through its extraordinarily long lifetime, preventing its market from becoming fragmented by customers exploring other options. Embedded applications are now realizing the performance and ease-of-use benefits of Intel's Core 2 Duo processors which, when combined with the extensive and flexible I/O capability possible within the VME profile, extends VME's potential to a much broader application base.
Support of embedded applications
The Intel x86 family has not been first choice for real-time, embedded military applications due, in part, to commercial decisions made during the early years of COTS adoption. High power dissipations of certain devices have also demonstrated unfavorable MIPS-per-watt comparisons when implemented within the constraints of VME and other similar modular systems. As a result, the x86/Pentium was never featured as the primary processor choice for VMEbus systems. However, the commercial environment that prompted those earlier decisions has gradually swung back toward longer product life cycles and support of embedded applications; this, in turn, makes VMEbus a market to be taken seriously. In addition, the new 45 nm process technology of Intel's T9400 Penryn family of Core 2 Duo devices now provides 64-bit, dual-core processors clocked at 2.53 GHz and a 1,067 MHz front side bus with an overall power dissipation of 35 W: well within the power dissipation envelope of VME.
Although unlikely to challenge the dominant position of Freescale's e-600 core-based PowerPC line in the military's critical, real-time, and signal processing applications, the x86/Pentium is well established in infrastructure projects such as logistics and battle management. It is additionally deployed in embedded form in combat systems, test equipment, simulation, and training systems. Compared to many prepackaged, commercial alternatives, VME-based products still offer the greater choice of I/O capability and performance. The primary reason is that VME is supported by an industry infrastructure honed to the needs of the embedded developer, including vital longevity of supply and support. Many small form factor products, such as MicroTCA or PC/104, might seem to offer a more economical alternative at first sight but they tend to be I/O or performance bound. Often the addition of all the required capabilities results in overall system size and costs that compare badly to a VME alternative.
The wealth of I/O capability traditionally offered by VMEbus products has been further boosted by the widespread introduction of PCI Express, rapidly displacing PCI and PCI-X as the preferred form of I/O connection. PCI Express provides significant board real estate and routing savings, with the capability to be routed to PMC/XMC mezzanine expansion sites offering greater flexibility and performance for the latest generation of SBCs. PCI Express can also be used for board-to-board expansion, adding more PMC/XMC sites within the two-slot envelope of just an SBC and an adjacent expansion board.
Even though VME has so many associated standards for connecting fabrics, mezzanines, and I/O, it continues to offer scope for competitive differentiation of processor cards. The x86/Pentium SBCs must, of course, offer basic PC functionality, BIOS, and Windows support as necessary prerequisites. However, vendors will eternally innovate to achieve additional flexibility, performance, or I/O channels in their latest products. This is illustrated by the V7875 Core 2 Duo SBC from GE Fanuc Intelligent Platforms shown in Figure 1. It includes support for the VXS (VITA 41.3) switched data plane using GbE and has a unique PCI Express extension capability to add three PMC/XMC sites via an expansion board. This provides a site supporting 16-lane PCI Express intended for demanding graphical applications such as simulation and training that require high-performance, high-definition 3D rendering using advanced graphics engines such as ATI's Radeon E2400.
Figure 1: VME continues to offer scope for competitive differentiation of processor cards, but vendors will eternally innovate to achieve additional flexibility, performance, or I/O channels in their latest products.
(Click graphic to zoom by 1.3x)
The T9400 Core 2 Duo Penryn family offers an ideal processor platform for new VMEbus product development. It provides unmatched 64-bit performance for the vast majority of applications. It also provides power consumption and longevity of supply and support that are firmly aligned with the needs of the VME and military communities. Meanwhile, the Core 2 Duo appears set for more widespread adoption in future military embedded programs.
To learn more, e-mail Duncan Young at [email protected].