FireSpy 400 Editorial

Complying with IEEE1394 a hands-on approach with Fire Wire analysers

The FireSpy400 is an IEEE1394 analyser that has been designed for all hard and software developers involved with IEEE1394-applications. Originally developed as 'Fire Wire' by computer company Apple to interface multimedia applications, the technology has been standardized as IEEE1394 by the IEEE."It is expected that all major computer brands will have equipped their new PCs with IEEE1394 within two years from now", says Jan de Vries, Managing Director at DAP Design.

About the technology

IEEE1394 uses inexpensive cables and simple connectors. The communication protocol, however, is a lot more complex. Four layers cover the whole protocol: the 'physical layer' including functions for bus initialization and cable interfacing, the 'link layer' which transmits and receives 1394-formatted data packets, the 'transaction layer' responsible for transferring data between applications, and the 'bus management' layer which ensures correct bus usage.

The Analyzer

With the enormous amounts of data of different origins that have to be processed, designers who start using IEEE1394 in building a multimedia application need a good Analyzer. FireSpy400 main components are a 1394 physical layer chip from Texas Instruments, a Xilinx programmable logic chip (FPGA) and a 128Mbyte memory module. The hardware supports data speeds up to 400Mbit/s and fits in a compact sized instrument. The debugging software runs on different platforms including Windows 98/2000 and soon Macintosh OS9. The debugger is connected to the computer via a USB port and can analyse the IEEE1394 bus using four basic functions, Monitor, Recorder, Commander, and Traffic Generator, ran either separately or simultaneously.

The Monitor gives a quick indication of bus activity such as the number and kinds of packets passing the bus. Events and packets can be stored in the internal memory and viewed later, at a number of levels. The lowest level shows timing, enabling one to view the timing of events and packets at a resolution of 20ns.

With the Commander one can read and write the so-called phy-registers of devices connected to the bus, read and write their memories, send user defined packets and view the bus topology.

Finally, the Traffic Generator can generate large amounts of asynchronous and/or isochronous data for testing the bus under heavy conditions.