Thanks to the magic of today’s level of semiconductor integration, multi-function board products have emerged enabling military system designers to blend a variety of I/O functions onto a single stand-alone card or PMC, XMC or AMC mezzanine card. The challenge has been to choose I/O technologies that are suited for use together. Among the most successful areas along those lines is the strategy of mixing multiple channels of 1553, ARINC-429, Serial I/O and other interfaces on one card.

While still an avionics bus at heart, the MIL-STD-1553 bus continues to play a role in a wide variety of systems such as tanks, ships, missiles and satellites. For example, The B-2 Spirit bomber’s (Figure 1) avionics systems are the heart of the stealth bomber’s combat capability, linked together through a 1553 network. Several vendors continue to support 1553 with board-level solutions that provide 1553, often included with other functions. Among those vendors are AIM-USA, Aitech Defense Systems, Alpha Technology, Ballard Technology, Curtiss-Wright, Data Device Corp., Excalibur Systems, GE Fanuc and Kontron America.

Multi-Function PMCs

Exampling the mezzanine side of multi-function offerings, Aitech Defense Systems offers a compact, multi-I/O PMC that provides a variety of configuration options for the highest levels of flexibility in different I/O environments. The low-power, single-width M705 features an unprecedented level of PMC density with up to five dual-channel, dual-redundant MIL-STD-1553B channels, 16 ARINC-429 receive channels and eight ARINC-429 transmit channels, up to six RS-232/422/485 serial channels and eight opto-isolated digital discrete input channels, all of which reduce the number of I/O cards required when developing subsystems. Additional board options include an ARINC 708 Weather Radar interface contained as VHDL within the large onboard FPGA.

The MIL-STD-1553 (STANAG 3838) channels support BC/RT/MT operation modes and offer 128 Kbytes (64K words) of dual-port RAM per channel. The discrete input channels serve as general-purpose I/O ports that connect to the GPIO FPGA, but are primarily used to externally assign the RT address to the MIL-STD-1553 channels. The PMC is available in the widest temperature range of -55° to +85°C (-67° to +185°F) and with software in rugged and military levels of ruggedization.

Stand-Alone PC/104-Plus

The multi-function trend has even reached the realm of small form factor cards. An example is Ballard Technology’s PM429-2 (Figure 2), a PC/104-Plus-compliant card for ARINC 429 and ARINC 717 avionics databuses. The PM429-2 offers up to 16 ARINC 429 channels and 4 ARINC 717 channels on a PC/104-Plus platform. Another attractive feature of the PM429-2 is its universal API library, which allows developers to program software on a commercial or other Ballard product such as an Ethernet or PCI card and seamlessly import it to the PM429-2.

In addition to these capabilities, the PM429-2 provides an IRIG timer and 16 input/output avionics discrete I/O signals. The discrete I/O can be used as general-purpose I/O or as trigger inputs and sync outputs for protocol functions. The PM429-2 discrete output circuits are open-ground switches capable of sinking up to 200 mA and can withstand up to 35 VDC applied to the pin. The discrete I/O are capable of interfacing with industry standard avionics discrete signals.

CANbus and 1553 Together

In the case of multi-function board specialist North Atlantic Industries, 1553 was added to their existing set of multi-function solutions. North Atlantic Industries (NAI) earlier this year added MIL-STD-1553 and CANBus functions for its wide range of VME, cPCI and PCI multi-function boards. Known as N7, N8 (Figure 3) (MIL-STD-1553) and P6 (CANBus) modules, they provide two dual-redundant MIL-STD-1553B Notice two interface channels. Each channel can be configured to act as a Bus Controller (BC), Remote Terminal (RT) or Monitor (MT). Features include 128 Kbyte (64K words) onboard memory per channel, register compatibility with the Summit family of devices from Aeroflex, support for automatic message return, and Automatic Health Monitoring (BIT). The P6 module provides four independent, isolated channels of Control Area Network (CAN) serial data bus links, conforming to the ISO 11898 International Standard.

The ARINC 429 bus is an interface that certainly makes sense to share with 1553. Data Device Corp updated its Multi-I/O MIL-STD-1553 / ARINC 429 USB Avionics Device product BU-671023UX. The BU-67103UX Multi-I/O MIL-STD-1553 / ARINC 429/575 USB Avionics Device is ideal for lab applications, while the BU-67102UX provides the same functionality in a more rugged package. The devices are available with up to two dual redundant 1553 channels, each capable of operating in Bus Controller (BC) or Multi Remote Terminal (RT) modes, with a concurrent Bus Monitor (MT). In addition, the device contains four ARINC Receive channels, two ARINC Transmit channels, eight Digital Discrete I/Os, IRIG-B Time Code input and one Pulse-Per-Second (PPS) output. Also available in 1553 and ARINC-only models.

The cards feature a common test/embedded API, and are supplied with a wide array of software including the BU-69092SX series software, which is DDC’s MIL-STD-1553 AceXtreme C Software Development Kit (SDK), including source code samples and detailed documentation. The USB Avionics Devices additionally include the DD-42992SX ARINC 429 Multi-I/O C SDK, incorporating source code samples and detailed documentation. Additional software packages include the BusTrACEr 1553 Graphical Analyzer/Simulator and dataMARS Real-Time Avionics Bus Analysis software.

Aitech Defense Systems
Chatsworth, CA.
(888) 248-3248.
[www.rugged.com].

Ballard Technology
Everett, WA.
(425) 339-0281.
[www.ballardtech.com].

Data Device Corp.
Bohemia, NY.
(631) 567-5600.
[www.ddc-web.com].

North Atlantic Industries
Bohemia, NY.
(631) 567-1100.
[www.naii.com].