REAL-TIME ADA APPLICATIONS WITH SILICON EXECUTIVES

Sextant Avionique plays a significant role in major commercial avionic programs, particularly within the Airbus family. In space activities, the company makes a key contribution to Ariane 4 and 5, and is involv ed in the Hermes spaceplane. In the defence sector, it participates in numerous programs (Mirage 2000 family, Rafale, Tigre, etc). The Ada l anguage has been used for several years in the development of embedded real-time applications for these domains. The major characteristics o f these applications are: long life: 20 years and more, dependability and certification, hard real-time: time and space constraints, specifi c hardware, software portability and re-usability. For more than 10 ye ars, we have been developing and studying synchronous and asynchronous real-time executives. OTR (operateur temps reel = real-time coprocess or) is the result of this experience. It is a hardware executive kerne l in silicon (ASIC: application specific integrated circuit) which was designed to meet the requirements of complex hard real-time on-board functions with cyclicity and asynchronous needs. The OTR coprocessor i s independent of both programming languages and microprocessors. It is an executive for the multimicroprocessor board including heterogeneou s microprocessors and, of course, the single-processor environment. Th e OTR-Ada services are available through an Ada package. This paper de tails the OTR concepts, the objectives and the services managed by the ALSYS/68020 and the TELESOFT/88100 OTR-Ada connections.