In recent years, two seemingly conflicting technology
trends have affected many rugged embedded aerospace and
defense applications. First, system designers have witnessed rapidly
increasing requirements for processing speed, bandwidth, and
distributed processing through the adoption of serial fabrics. Meanwhile,
size, weight, and power (SWaP) are critical design considerations
for emerging applications such as unmanned aerial vehicles
(UAVs) and technology-insertion upgrades of already crowded existing
platforms.
Previously, system integrators who were confronted with these
competing demands had to compromise their design or turn to
proprietary and costly integration options. The lack of an openstandard,
high-performance, small-form-factor board architecture
constrained the choices.
Until now, 3U CompactPCI (cPCI) represented the best option
for a small-form-factor board. However, a six-slot, 32-bit cPCI bus is
limited to a maximum transfer rate of 33 MHz or 133 Mbytes/s. Also,
implementing a switched serial fabric such as Serial RapidIO (SRIO)
or PCI Express (PCIe) requires the use of serial-to-parallel bridge
conversion chips. While 3U cPCI remains a good solution for many
embedded applications, a better solution has emerged for demanding
high-performance systems.
3U VPX, the small-form-factor variant of the new VPX (VITA 46)
and VPX-REDI (VITA 48) open standards, can satisfy both sides of
the seemingly incompatible demands for more performance from
smaller cards. VPX’s MultiGig RT2 connector significantly raises the
performance bar, with support for 4 to 5 Gbytes/s for eight fabric
lanes of SRIO or PCIe. With the advent of 3U VPX, the days of rugged
small-form-factor compromise are over.
