The ATT PIM429T2 is a dual channel ARINC 419/429 Protocol Interface Module (PIM) designed to be fitted onto the ATT-DAS PC/16 and PCI/24 test and simulation carrier cards for PC/AT/PCI compatible computers

This 40 pin module plugs into one of 8 sites on the ATT-DAS PC/16 or one of 12 sites on the PCI/24 carrier card. A single PCI host card can accept up to 12 429T2 PIM’s which therefore permits up to 24 ARINC TX channels to be mounted onto a single board. Alternatively, the PIM429T2 can be mixed with other PIM types to build a multi-protocol system.

The PIM429T2 uses Harris line driver integrated circuits to drive the ARINC bus. The line drivers are fed from a custom logic array. Both channels of ARINC are fully independent, and have their own line driver chips and LCA transmitter circuits. Time multiplexing of the transmitters is NOT used.

The PIM429T2’s LCA can be configured to support almost and desired ARINC 419/429 format. It can be programmed to transmit at any bit rate from 6Khz to 800Khz. Word lengths can be programmed to be from 1 to 63 bits, inter-word gaps can be programmed to be from 1 to 127 bit times, output amplitude can be programmed in 16 levels from 0 to 5V, and the output slope can be set to one of 16 rates. All these settings are user programmable, and may be different between the two channels on the PIM.

Each ARINC 419/429 transmitter channel has a transmitter list and a transmit lookup table containing ARINC 419/429 words, both of which can be accessed via the dual port memory on the carrier card. Additionally, each transmitter maintains an internal instruction pointer (IP), a loop counter (LC) and a stack pointer (SP). These registers can be directly accessed.

The Transmitter list can be thought of as a program which controls the transmitter. The IP points to the next instruction in the transmitter list to be executed. When transmission is started, the transmitter zeros the IP and LC, and SP is set to the top of an internal stack. The first ‘instruction’ from the transmitter list is then read.

If the value of an instruction is between 0 and 4095 (0x0nnn), then the Arinc 429 word stored in the corresponding transmit lookup table is transmitted on the Arinc bus. Once all the bits of the word have been transmitted, and the inter word gap time has expired, the next instruction is read from the transmitter list.

If the value of an instruction is greater than 4095 then it is treated as a control code. The control codes can be used to implement loops, jumps and subroutines, to set the timing, voltage and slope of transmitted data, and to generate PC interrupts.

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