Signal Converter System Test Environment

The DAC International “Converter” is an integral component of a legacy aircraft avionics upgrade.  The “Converter” transforms the ARINC 429 digital data into analog signals compatible with the unmodified instruments and subsystems.  5‑D, in partnership with DAC International, developed the System Test Environment (STE) for their Converter product with DAC developing the hardware and 5-D developing the software. 


The STE is the primary test tool for software testing, hardware acceptance testing, and system testing.  The hardware is based on a variant of the 8051 microprocessor and includes several integrated peripherals.  We developed the peripheral drivers for both the integral (e.g. SPI, RS‑232) and external interfaces (e.g. A429).  The STE design did not include video support and was originally planned to interface with a separate software package for system control and monitoring.  To minimize the total hardware and software items, we developed a VT‑100 style user interface to control the STE, send stimulus signals/data to the Converter, and monitor Converter outputs.  In addition, we implemented a scripting capability via user defined to control A429 label output frequency and data content.