New standards and new design concepts are helping embedded systems designers keep pace with increasing demands for mobile capabilities.
Embedded computing systems have always offered a variety of readily available mix-and-match component solutions built around industry standards. But as increasing demands are spurred by more sophisticated mobile applications in imaging, communications, sonar, radar, and electronic warfare, they are forcing industry standards and suppliers to keep pace.
FMC+ Opens New Channels
Field-programmable gate arrays (FPGAs) have long been an attractive source of versatility in embedded computing applications. Mounting them on mezzanine cards that attached to a carrier card – instead of plugging directly into a backplane – provided both configuration flexibility and an easy way to upgrade technology over time. Another advantage of the FPGA mezzanine cards (FMCs) with direct I/O connections to the host FPGA was that they did not require a lot of board space for a bus interface, so despite their smaller size they could deliver more I/O capacity.
“But as the I/O channel speeds supported by new FPGAs are rising, they are driving the need for higher-speed mezzanine connections,” says Michael Munroe, a technical product specialist at Elma Electronics. He cites the emergence of the VITA 57.4 FMC+ standard as an opportunity for embedded designers to harness increased capability from their FPGA mezzanine cards. The draft standard was recently approved by the VITA working group and is planned for submission to ANSI balloting later this summer.
The new standard provides the capacity to handle both higher I/O speeds as well as a greater volume of gigabit transceivers (GTs) to increase the maximum data rate, all while maintaining backward compatibility with the original VITA 57.1 FMC standard.
By building on the original FMC connector design and adding to the FMC connector’s outer columns for additional signals, the new FMC+ standard enables a user to support up to 24 GTs – with an option for up to 32 GTs when using an added HSPCe connector – instead of the 10 GTs supported by the original FMC standard. It also supports a maximum data rate of 28Gb/s instead of the 10Gb/s rate supported by the original FMC standard.
Mil/Aero Market Alternatives
The SWaP – size, weight, and power – concept has really taken root in military-market embedded-computing applications. While the electronics have shrunk appreciably, the old tried-and-true mil-spec connectors (and not necessarily the size of the new electronic components) still tend to define the size of the chassis. Part of the reason is the “want” for more miniaturized connectors in that sector comes with a “need” for rugged performance reliability.
“The US military is always looking to reduce system downtime and would prefer vehicle electronics to be field-replaceable, so they do not have to drive – or tow – a vehicle to the rear echelons to pull and replace a faulty electronics unit,” says Doug Patterson, vice president, Military & Aerospace Business Sector, at Aitech Defense Systems. “Truly rugged, miniature connectors would help this effort greatly.”
One way Patterson’s company is addressing the reliability issue is by examining and experimenting with more robust diagnostics and system-level prognostics. The goal is to engineer those attributes into electronic systems to help identify when connectors are nearing their end of life.
In terms of communication protocols, Patterson notes that standard 802.3 Gb Ethernet is displacing the once prominent MIL-STD-1553B for high-speed data transfer in some rugged military embedded applications, but it is not always the universal answer. “The 1553 standard is still being used for tight, closed-loop machine control/flight surface controls due to its inherent redundancy and real-time performance,” Patterson says. “Either way though, we really don’t see that transition impacting connector decisions, since standard circular MIL-DTL 38999 and D-Sub connectors work just fine at those frequencies, with plenty of noise margin left over.”
Author Peter Antoniewicz is a veteran freelance writer who covers high-tech and business-to-business topics for a variety of corporate, agency, and editorial clients. He has written on subjects ranging from embedded computing, electronics, and software to ag-chem, medical imaging, engineered solutions, industrial products, and business services. Email him at firstname.lastname@example.org.