TECHNOLOGY FEATURE
Data links
sFPDP: Optimized Data Transport By Patrick Mechin and Philippe Marvin
Today’s sensors can collect and generate huge amounts of data, all of which must be moved somewhere for processing. There are several alternatives for communication links between sensors and processing elements. Designers want to benefit from the highest-speed protocols available to design or upgrade their systems. A popular choice is Ethernet, but there are alternatives: One of those choices is serial Front Panel Data Port (sFPDP) – as defined by VITA 17.1 – which presents a low-latency protocol for sensor data interconnection that is widely used by the military embedded industry. The original VITA 17 standard, called Front Panel Data Port (FPDP), was defined to meet the need of high-speed and optimized communication between two points inside a processing cabinet, usually two VME racks. The FPDP bus was intended to provide data transfer between two or more VMEbus boards at up to 160 MB/sec with the lowest possible latency, while not compromising existing VMEbus and other connections on the chassis P1 and P2 connectors. FPDP was connected by means of an 80-conductor ribbon cable connector at the front panel of the VMEbus board. The wiring topology was in the form of a bus and multiple FPDP busses may coexist in a single VMEbus enclosure. FPDP was restricted to short distances (less than 1 m or 3.28 feet), mainly point-to-point and based on a very lightweight protocol focused on efficiency rather than functionality. Beginning in the early 2000s, communication buses started moving from parallel to serial to offer higher bandwidth and longer distance capabilities. the VITA 17.1 serial FPDP (sFPDP) was created for the embedded industry. The initial instance, released in 2015, supported data rates up to 10 Gbaud. As in the original parallel bus version, sFPDP is simple to implement and use. Engineers can implement it within an FPGA [field-programmable gate array] or ASIC with little difficulty.
22 | VITA Technologies with Resource Guide Spring 2021
sFPDP is a well-known protocol in defense, research, and medical markets. Major key players – Abaco Systems, Curtiss-Wright, Galleon EC, Mercury Systems, Pentek, and others – have designed many products to simplify the implementation of sFPDP that do not require additional FPGA development by the user. These products are used in embedded applications through rugged XMC modules or in lab equipment (data recorders or test benches). Thanks to widespread deployment, sFPDP is a staple for real-time applications in the field of sensor/computer links. Thanks to these advantages, the sFPDP protocol has been widely adopted by the defense engineering community for applications in which high-speed links and real-time are mandatory. For example, www.vita-technologies.com