Real-time Ada applications with silicon executives

Abstract 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 involved in the Hermes spaceplane. In the defence sector, it participates in numerous programs (Mirage 2000 family, Rafale, Tigre, etc). The Ada language has been used for several years in the development of embedded real-time applications for these domains. The major characteristics of these applications are: • - long life: 20 years and more, • - dependability and certification, • - hard real-time: time and space constraints, • - specific hardware, • - software portability and re-usability. For more than 10 years, we have been developing and studying synchronous and asynchronous real-time executives. OTR (operateur temps reel = real-time coprocessor) is the result of this experience. It is a hardware executive kernel 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 is independent of both programming languages and microprocessors. It is an executive for the multimicroprocessor board including heterogeneous microprocessors and, of course, the single-processor environment. The OTR-Ada services are available through an Ada package. This paper details the OTR concepts, the objectives and the services managed the ALSYS/68020 and the TELESOFT/88100 OTR-Ada connections.