| Some embedded real-time systems have hardware elements that naturally interfere with each other, preventing their simultanious use. The primary example studied in this thesis, among others, is that of a switch-mode power supply (SMPS) driving a Dynamic Voltage and Frequency Scaling (DVFS) embedded system containing other hardware elements which, by either necessity or design, are prone to sulfer interference. In this configuration, these hardware elements can be considered rivalrous, an economics term for goods which cannot be used correctly by more than one entity at a time. However, thanks to our deployment of Rivalrous Hardware Scheduling (RHS) which allows the application of real-time scheduling techniques to rivalrous hardware tasks, we can allow the temporal isolation of otherwise incompatible (e.g. noise-generating and noise-sensitive) tasks without interference, all the while minimize energy consumption and satisfying hard realtime deadlines. We demonstrate these proposed scheduling techniques and other concepts by building them into several embedded platforms, including underwater communication and down-well communication. Another contribution of this dissertation is to demonstrate various novel benefits from building up the walls of abstraction between embedded system hardware and software through the use of automated code and scheduling analysis. This abstraction allows the deployment of various stages of automated code design, bridging the gap between the need for embedded systems and the difficulty in their design. To this end, we have developed new methods and implemented them in various tools enabling the rapid prototyping of various stages of embedded systems design. One such tool is the RaPTEX toolchain, which allows users to utilize the modular interface to simplify the creation of new custom applications, alleviating the need for high-level user design decisions, which can be handled by the toolchain. This presents three main areas of contribution to the research community. The first area of contribution is to the area of Real-Time Scheduling (RTS), where the novel concepts of Rivalrous Hardware Scheduling (RHS) and Quasi-Static Scheduling (QSS) bring the application of existing software scheduling theory to schedule hardware tasks, with demonstrable benefits. The second area consists of the challenges faced and lessons learned while developing a series of ultrasonic communication systems, for communication in shallow water channels and then for down-well communication on a drilling platform. The final area of contribution is the design and implementation of Automated Tools to aid designers to more quickly and thoroughly deploy unique embedded systems. |
