High-integrity interfacing to programmable logic with ada

Abstract

Programmable logic devices (PLDs) are now common components of safety-critical systems, and are increasingly used for safetyrelated or safety-critical functionality. Recent safety standards demand similar rigour in PLD specification, design and verification to that in critical software design. Existing PLD development tools and techniques are inadequate for the higher integrity levels. In this paper we examine the use of Ada as a design language for PLDs. We analyse earlier work on Ada-to-HDL compilation and identify where it could be improved. We show how program fragments written in the SPARK Ada subset can be efficiently and rigorously translated into PLD programs, and how a SPARK Ada program can be effectively interfaced to a PLD program. The techniques discussed are then applied to a substantial case study and some preliminary conclusions are drawn from the results.