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Engineers now required to plan, integrate, or test data channels (data buses) of the avionics can choose from a range of commercial interface card components off the shelf (COTS – Commercial-Off-The-Shelf). For special application, choosing the optimal exercise requires an understanding of architectural alternatives. Military and commercial avionics protocols (MIL-STD-1553, ARINC 429, ARINC 708 and others) longevity almost no changes for over 20 years. But during this period, hardware interfaces avionics data channels increased capabilities and small size.

Although avionics protocol determines the basic functions and application sets the product requirements, the data bus interface architecture Hawioneime dictates the limit. Even for the same protocol, the ability and ease of use vary depending on the different Lmimoshim. Interfaces for applications that include basic communication, and imaging hardware testing requirements have much in common, but you can also characterize these requirements – the differences between them. For example, the injection error (error injection) is a useful feature in the interface of the test, but never inject errors on – by the aviation application interface.

Here are some general considerations when choosing a data bus interface Evie

* Host Interface (PCI, cPCI, VMEbus, Ethernet Bridge, custom, etc.)
* Number of channels and protocols
* Involvement in the host protocol processing
* With the host interaction data
* Special features: monitoring, recording times, injection errors, etc.
* Processing power available for user application protocol
* Mac hardware and software development and support
* Development and production costs

There are three basic architectures: the IC protocol, single-processor and multi – processors. In some cases it would be difficult to characterize a special interface, but understanding the different architectures helps to raise important issues and handling them during the selection.

Architecture of protocol: this architecture, analog and digital circuit components are integrated to provide at least basic communication. These circuits have evolved, many components are available now with all the functionality integrated circuit (IC), a single, multi-module – chips (Multi-Chip Module, MCM) or hybrid circuit. Depending on the complexity protocol IC, the host processor may be required to perform higher levels of protocol. ICs of the protocol may be expensive, but the circuits that use the protocol ICs are relatively easy to implement and are a good choice when developing staple. Most of the ICs of a protocol designed for aviation applications (operational) when the requirements are limited to basic communication functionality. Because they are not providing special functions (such as creating schedules and registration errors), less protocol ICs are suitable for use in equipment testing. May be required an extensive software development to interface with the host, run a high-level protocol functions, and manipulate the data correctly. COTS interface cards manufacturers should provide driver functions that raid the examples of software development.

Single Processor Architecture: Adding processor improves ability and flexibility of the interface. IC of a protocol or a custom set goals demand often handles encryption and decryption, while running the firmware on the processor runs the protocol with a high level. High speed digital signal processor (DSP) makes it a good choice for the processor. Task-based interface development – from the core processor is much more heavily than for IC interface of a simple protocol. However, manufacturers of COTS VMEbus interface cards), cPCI, etc.) provide convenient functions usually firmware driver software with built-in wide. Error injection, monitoring, recording times, great imagery – the final special message handling are all possible thanks to this architecture.

Architecture multi – processor: The next step is increasing the progress of processing power. There is a growing industry need for more channels, protocols and codes can run mixed use, all single interface card. Digital components and dense packaging techniques enable it new. As the number of channels, more processing power is required to prevent the load – overload. DSPs work well as protocol processors, but processor for general use on a single card (eg PowerPC ® processor), which ran on a familiar operating system facilitates the development of user code.

Processor for general use can ease the load host or run user code. It can format, manipulate data and produce the most appropriate way to host and gives the user the flexibility to configure the software interface between the host and the interface card. In some cases beyond the user is all it takes to run the entire application and does not need a host processor. For example, the software for data servers and protocol converters can run on a ticket without a host processor support. Protocol converter receives many messages or protocol channel, performs the necessary conversion relays them back channel or a different protocol (eg MIL-STD-1553 to ARINC 429). Data Server provides users with controlled access to the many channels of data. He can even submit the data as an Ethernet network through a gateway.

An example of multi-architecture – processor bus interface is the new data Awioneime Ballard OmniBus ® Technology, available for PCI, cPCI, VMEbus and USB and Ethernet product called OmniBusBoxTM independent. Ethernet gateway of the VME OmniBus and OmniBusBox allows remote operation. The common architecture of the OmniBus allows seamless transfer of software applications on various platforms. All the products provide OmniBus PowerPC user processor (running on Linux) multiple DSP processors and protocol. There is a software management tool for the OmniBus. Users can develop their own programs or run CoPilot ® software, a powerful and friendly graphical interface. OmniBus supports-MIL-STD-1553, ARINC 429, 717, 708 perversions of these protocols, as well as serial discreet goals. Each product can be designed for a large number of channels on a single protocol, or on a variety of different protocols. For example, a cPCI card U3 can contain four channels of 1553, 32 channels or 429 channels in 1553 with two channels of 16 429.

Technological progress has expanded the variety of architectures available for avionics data channels. Equipped with its capabilities and flexibility, the engineers should seriously consider using multi-architecture – the new processors. In the end, compromises between economic and performance considerations determine the solution chosen for a particular application. Choice, the engineers have to assess the development of hardware and software purchase costs against mixing protocols, the number of functional requirements channels.