By John McHale
LONG BEACH, Calif. — Plans are in the works for a new VME specification that would enable conduction-cooled VME circuit boards to meet the growing demands of military and aerospace systems designers for wideband I/O, fast processing, and power distribution.
Officials at Dy 4 Systems in Kanata, Ontario, Mercury Computer Systems in Chelmsford, Mass., Radstone Technology of Towcester, England, and Vista Controls in Santa Clarita, Calif., are united in their support for the proposed standard — VITA 46. VITA stands for the VME International Trade Association in Fountain Hills, Ariz.
VITA 46 will move data through the backplane via 10-gigabit-per-second serial-switched-fabric data paths, as well as via VME parallel backplane databus protocols that move data at 32, 64, and 320 megabytes per second. It provides four serial-switched-fabric ports in the initial configuration, and the capacity for more than 20 ports in fabric-only configurations.
VITA 46 would replace VME DIN connectors with fundamentally different high-speed connectors, which are not compatible with DIN-connector VME 32, VME 64, or VITA 41 cards.
Despite the lack of backward compatibility of the VITA 46 connector, the new standard would enable systems designers to mix VME 32, VME 64, and VITA 41 DIN connectors on the same backplane with the new VITA 46 connectors. This was a key concern of systems designers who demand backward compatibility.
In addition, VITA 46 would allow designers to mix 3U PCI DIN connectors with 3U VITA 46 connectors on the same backplane. The specification also addresses high-speed connectors for harsh environments; The VITA 46 working group is addressing issues involving stress, vibration, and conduction cooling.
VME 32, VME 64, and VITA 41 move data respectively at 40, 80, and 320 megabytes per second. High-speed serial interconnects can move data in the multi-gigabit-per-second range.
Suppliers of commercial off-the-shelf (COTS) components for military applications say they formulated VITA 46 to address shortcomings in current VME specifications that do not provide a practical way for conduction-cooled 6U and 3U VME to use high-speed switched interconnects such as Serial RapidIO and PCI Express.
No VITA standard other than VITA 46 has brought high-speed signaling support to the 3U form factor, Mercury officials say. The relatively small 3U circuitcard form factor is becoming increasingly important as systems designers can pack large numbers of tiny electronic components on the small boards.
Essentially VITA 46 is not VME; it is a something different that eventually will have a different name once it becomes official next year, says VITA Director Ray Alderman. A white paper detailing backward compatibility issues will be released after the VITA Standards Organization meetings later this month, Alderman adds.
"VITA 46 addresses the key issues involved in bringing switch fabrics to deployed military systems," says Eric Gulliksen, embedded hardware practice director at Venture Development Corp. in Natick, Mass. "This is vital to ensure the growth of the VME architecture over the next several years."
VITA 46 Working Group participants also include Boeing, FCI, Foxconn, Hybricon Corp., the Naval Surface Warfare Center Crane Division, Positronic Industries, Pentair/Schroff, Tundra Semiconductor, and Tyco Electronics.
A draft standard will be available this June with validation testing set for the summer and early fall. Final approval of the standard should occur by January 2005. For more information on VITA and its standards go online at www.vita.com.
