Execution Time Management for AVR32 Ravenscar

Abstract

This report describes how the new Ada 2005 execution time features was implemented for the GNAT bare-board Ravenscar run-time environment on the Atmel AVR32 architecture. Efficient and cycle accurate execution time measurement was achieved by utilizing the COUNT / COMPARE functionality of the AVR32. The implementation also addresses inaccuracies reported by earlier implementations by supporting separate execution time measurement for each interrupt level and taking into account the effects of executing protected entries by proxy. An example application utilizing the execution timers within the restrictions of the Ravenscar profile is given.