This module occupies four of the sites on the ATT-DAS PCI carrier cards. PIMs are available for ARINC 419/429 Transmitters and Bus Monitors, Panavia Transmitters and Receivers, RS232/422/423 Bus Monitors, Mil-Std-1553A/B Bus Monitors and STANAG 3838/3910 Bus Controllers, with others under development.

To allow much larger systems to be constructed, it is possible to install multiple PCI carrier cards into a single PC so systems containing multiple Mil-Std-1553 channels can be built. The system clock can be daisy chained across boards to ensure that the time tag’s on different boards do not drift with respect to each other due to crystal tolerances.

The M1553BC PIM uses two Bus Isolation Transformers to connect to the Mil-Std-1553 bus, one for each of the Dual Redundant Busses. This provides maximum isolation for both the unit under test, and the host PC. The outputs from the transformers are fed via line receiver chips to a custom logic array.

The M1553BC’s monitor LCA receives and decodes the incoming messages. It can detect which of the two dual redundant busses the data was received on, and Sync, Manchester or Parity encoding errors that exist on a word by word basis. This information is reported to the host PC via the dual port RAM on the ATT-DAS PCI carrier card.

(Picture not to scale, PIM occupies 4 sites on the carrier card. Physical dimensions 105mm x 45mm.)

The ATT PIM 1553BC is a powerful bus controller with an extensive bus instruction set. Bus instructions include all the Mil-Std-1553 commands with Jump to sublist, Jump on Status Exception, Jump on Protocol Error, Return, Unconditional Jump, Reset Stack, Wait, Delay, Pause, Halt, etc. An interrupt can be enabled allowing the host computer to follow or react to each instruction.

In Acquisition mode, each Bus Monitor channel can filter and time tag the data to 1uS accuracy. Acquired data is placed in a buffer for subsequent reading by the host computer and recording to disk. An interrupt can be generated when the data is captured. Acquisition is concurrent with other modes of operation.

Each Mil-Std-1553 interface supports a full chronological monitor which can capture all bus traffic or specified transactions. Received words which fulfil the monitor conditions are time tagged to 1uS accuracy and placed into a dual port RAM buffer for the host computer to analyse or transfer to another storage medium. Interrupts can be used to notify the host system of specific events. All other modes can operate concurrently with the monitor mode.

For a turn-key solution to many applications, a menu driven software package running under Microsoft Windows is available, see http://gssprojects.com.

For users wishing to write their own software, an Application Program Interface (API) complete with source code is available. Written in Microsoft C, this code can be compiled into a library suitable for both Windows and DOS based applications. It can also be compiled into a self contained Windows DLL.