What’s New in 1553?

Mil-Std-1553 remains a dynamic area of avionics, and the technology continues to evolve, embracing packaging and software innovations, faster processors and local area networks, as well as reaching toward truly high-speed implementations.

The Mil-Std-1553 market continues to evolve. Many suppliers plan releases in 2006, focusing on intellectual property (IP) cores, high-density circuit cards, network-readiness and innovative software tools.

Mil-Std-1553 IP cores–software versions of the digital circuitry–are being used in small-footprint, high-volume applications, as large field programmable gate arrays (FPGAs) become more affordable. Data Device Corp. (DDC) and Condor Engineering are building their product lines.

While the big news around DDC is the successful flight test of its new high-speed 1553 terminals, Todd Decker, DDC’s marketing manager for 1553, says that legacy 1553 products will continue to be developed and supported. DDC released a 32-bit ACE Flex-Core IP core in September. The BU-692X0IX core incorporates DDC’s new Extended Enhanced Mini-ACE (E2MA) architecture with multiple remote terminal (RT) capability, short access time and extended memory features.

"Back in the late 1990s, FPGAs weren’t large enough to handle 1553," says Decker. "With today’s FPGAs’ getting larger, we’re seeing more interest in them. The new Flex-Core takes up fewer gates and represents an enhancement [over the ACE IP core]."

DDC introduced the Flex-Core IP cores, which used its Simple System Remote Terminal (SSRT) architecture, in 2004 and released the 16-bit Flex-Core early last year. The 32-bit Flex-Core allows customers to choose a core to perform one of several bus controller (BC), RT, monitor terminal (MT) or combination functions.

Condor Engineering released its multifunction FlightCORE-1553 IP core last year. Touted as the first multifunction, simultaneous BC, single RT, and MT 1553 IP core for embedded designs, the FlightCORE-1553 product allows implementation of 1553 functionality in Xilinx and Altera FPGAs.

IP Protection

FlightCORE also includes a "personality module," which is used to track IP licenses and verify the application’s right to use the Condor software.

"Condor believes that in the long run, ASIC [application specific integrated circuit] architectures are more costly and risky, when compared with FPGA designs," says Bill Schuh, Condor’s military products manager. "Our new FlightCORE-1553 product…enables engineers to simulate many more inputs while in the prototype stage and thus get their products to market faster."

Since the FlightCORE-1553 IP products are designed for customers creating their own cards for use in flight, they provide analyzer-level data in addition to completing normal 1553 data functions. "FlightCORE provides embedded 1553 functionality with the ability to do diagnostics," says Schuh. "Customers know the condition of the bus and what’s going on in the bus. Now they don’t have to see [only] that [the bus] missed a message; they can find out why [the bus] missed a message." Schuh says most customers can integrate FlightCORE-1553 technology into their products in less than three days.

FlightCORE-1553 products are sold under a software license that does not require royalty fees and works with other non-1553 transceivers. Customers could use FlightCore-1553 with RS-485 transceivers, costing approximately $3 each instead of 1553 transceivers, running between $60 and $200 each.

This quarter Condor plans to add a FlightCORE product for the flight control actuator data bus (FCAB), a 10-Mbit/s Mil-Std-1553 bus using RS-485 transceivers in a multidrop, as opposed to a star, configuration.

Test Cards

AIM GmbH recently introduced its fourth-generation, PCI-X-compatible line of cards for 1553 test, simulation and monitoring applications. Dubbed APX1553, the cards provide up to four independent, dual-redundant streams on a single, short-length PCI/PCI-X-compatible module. They can perform concurrent BC, multiple RT and MT functions and are available in full-function, single-function and simulator-only versions.

The APX1553 cards offer one or two 400-MHz XScale processors for the bus interface units (BIUs) and an additional 400-MHz Intel input/output processor (IOP) application support processor. AIM also is working on a new PCI mezzanine card (PMC) for test, simulation, monitoring and data bus analyzer functions. The AMC 1553-4 PMC card will contain four independent and dual-redundant 1553 channels for use in the test environment as well as in embedded solutions. Like the APX 1553 test cards, the AMC 1553-4 cards can be configured as single-function BC, RT and MT cards or handle BC, multiple-RT and chronological monitor functions on all channels concurrently.

The AMC 1553-4 cards can be configured to "take out some concurrent operations not normally required for embedded airborne Mil-Std-1553 applications," says Doug Ullah, AIM’s sales and marketing director. "Normally, embedded solutions wouldn’t use concurrent operations, but the capability is there for test and simulation. It’s the same card; just the firmware loaded is different."

An AIM test and analysis tool called MILScope is scheduled for release sometime in 2006. MILScope will allow users of the new APX1553 cards to verify waveforms and detect faulty conditions without the use of an external oscilloscope. Customers will be able to measure bus parameters, such as rise and fall time, overshoot, pulse width and signal amplitude.

Flight Cards

Released in September 2005, National Hybrid Inc.’s (NHI’s) new VME mezzanine card contains up to four independent, dual-redundant 1553 terminals, each of which can handle all 1553 functions.

The terminals are independent of each other in the NHI-15505PMC card, says National Hybrid President and Chief Executive Officer Roy Nardin. "If one terminal goes down, the other terminals still work. Other cards use FPGAs, which means that if the FPGA goes down, all terminals are down."

The ruggedized NHI-15505PMC card operates in military and industrial temperature ranges and comes with NHI’s Flight Deck software for configuration and a run-time library for application development. Each terminal on the card contains 64Kwords of internal random access memory (RAM) and can be configured as an RT, BC, monitor, or monitor/RT.

"The auxiliary function of the combined monitor/RT [serves] as a backup bus controller," Nardin says. "If the bus controller realizes that it’s dying, it has to turn over control to [another terminal] that has been collecting all of the data that the bus controller has been sending out. It can’t turn over control to a remote terminal because that terminal doesn’t know what happened to all the other terminals."

NHI also plans a new 1553 transceiver. Scheduled for release late in the first quarter of 2006, the 3.3-volt transceiver, in a 7-mm package, will handle both Mil-Std-1553 and Mil-Std-1760 applications simultaneously. "When people buy just a transceiver and not the rest of the terminal, they’re buying it for an FPGA with a 1553 IP core solution," says Nardin. "The IP solution is cast in stone. If there are wide variations in the 1553 parameters [between lots], the customer may have to throw out the transceivers ordered that don’t meet the required parameters." If the transceivers are going to be used with IP cores, "you have to have very conservative, controlled parameters."

Holt Integrated Circuits Inc., meanwhile, has introduced its HI-1575 1553, 3.3-volt "smart dual transceiver." The part features an integrated encoder/decoder that allows users to eliminate the implementation of the Manchester encoder/decoder. The HI-1575 is designed to interact with FPGAs or host processors and meet the word-level requirements of Mil-Std-1553, while handling the analog and time-critical parts of the interface.

Along the same lines, Aeroflex Plainview has announced a "universal transceiver," supporting 1553, 1760, MacAir (A-3818, A-4905, A-5232 and A5690), and H009 (F-15) bus operation. Designated the ACT4462D, the new transceiver is a variable-amplitude, dual-channel, pin-selectable multichip module with 24 leads. The unit operates at +/-12 volts and +/-15 volts with +5-volt logic power supplies.

Curtiss-Wright Embedded Computing also has introduced the Rhino MX Dual 7457/1553 conduction-cooled, single board computer with a 1.3-GHz PowerPC and two dual-redundant Mil-Std-1553 interfaces.

Data Acquisition

Excalibur Systems has introduced two data acquisition products. The first, a ruggedized handheld personal digital assistant (PDA) known as the Lance, also can function as a 1553 monitor. It provides portable ARINC 429 data acquisition on up to 10 channels as well as dual-redundant 1553 monitor functions. At $7,495 list price, Lance contains a 5-Gbyte hard drive, 64 Mbytes of RAM and a 400-MHz Intel XScale processor. Hosted on a Windows Mobile for Pocket PC operating system, the unit typically is used to acquire data on the flight line and transport the data back to the lab for analysis.

A second product, the Dragon, is a ruggedized, modular, self-contained PC-104/PC-104 Plus system that stacks several cards for data acquisition and recording through different protocols, including 1553 and ARINC 429. The Dragon uses one of three processor cards, ranging from 400 MHz to 900 MHz, with up to 256 Mbytes of RAM, parallel and serial ports, two USB ports, a 10/100 Ethernet local area network (LAN) interface, power supply, a selection of Excalibur’s avionics communications modules, and connections for video, hard drive and PS/2 mouse.

By August 2006 Ballard Technology expects to expand its Omnibus family with a series of smaller, flightworthy data converters. The data converters will be functional equivalents of Ballard’s Omnibus boxes, says Kevin Christian, customer services manager.

Essentially PowerPC units preloaded with Ballard’s customized version of the Linux real-time operating system, OmniBus boxes convert Mil-Std-1553 data into several other protocols, and vice versa, including Ethernet, ARINC 429/708/717, avionics full-duplex switched (AFDX) Ethernet RS-422 serial port and avionics discretes. While Omnibus boxes are meant for laboratory prototyping, the new data converters will be flightworthy and will convert standard 1553 data to user datagram protocol (UDP) packets for transfer over Ethernet networks.

"Our customers are interested in integrating more data in the battle space," says Christian. Our market is the link between net centric warfare data and the legacy 1553 databus. We’re basically just a node on the network."

Testing High-Speed 1553

On Dec. 17, 2005, Data Device Corp. (DDC), with Boeing and Honeywell, completed a flight demonstration of DDC’s new high-performance HyPer-1553 technology on a Boeing F-15E1 advanced technology demonstrator. The team transferred data at 40 Mbits/s over an existing bus infrastructure while the legacy, 1-Mbit/s bus operated simultaneously. A second data bus dedicated to higher-speed transfer achieved rates of 80 and 120 Mbits/s.

In the test digital imagery was passed between a chassis in the aircraft’s forward equipment bay and a modified smart bomb on a wing pylon station. A DDC card with the HyPer-1553 interface was mounted to a Honeywell general-purpose processor at each end of the interface.

The demo proved, among other things, that high-speed 1553 technology is rugged enough to withstand the vibration and noise on the wing, explains Todd Decker, DDC marketing manager for 1553.

DDC is working on a new line of terminals, merging the high-speed 1553 with its ACE line. "We’ll introduce common technology that will be able to replace legacy systems with new [low-speed] capability on top of high-performance capability," Decker says. The high-performance terminal would include both high-speed 1553 and the "ACE terminal…able to talk at the old rate." DDC’s roadmap also calls for compatibility with the emerging Notice 5 requirements for Mil-Std-1553B technology.

Edgewater Computer Systems, meanwhile, claims a 200-Mbit/s Extended 1553 bus, developed with U.S. Air Force support. The technology is to be flight tested on an F-16 this summer, and the new Notice 5 standard derived from the work is expected out this month.

Companies

Actel Corp www.actel.com

Aero Express www.aeroexpress.com

Aeroflex. www.aeroflex.com

AIM GmbH and AiM-USA www.aim-online.com

Ampol Technologies. www.ampol-tech.com

Ballard Technology www.ballardtech.com

BCF Designs (UK) www.testbcf.com

Condor Engineering www.condoreng.com

Curtiss-Wright www.cwcontrols.com

Data Bus Products www.databusproducts.com

Data Device Corp www.ddc-web.com