On PTIDES Programming Model

1. John Eidson • Jeff C. Jensen • Edward A. Lee • Slobodan Matic • JiaZou Analysis Schedulability Analysis On PTIDES Programming Model Causality Analysis Program Analysis Ptides Model Code Code Generator PtidyOS HW Platform Software Component Library • Distributed Real-Time System Implementation • Programming Model • Programming Temporally Integrated • Distributed Embedded Systems • Based on Discrete-Event semantics • Event processing in time-stamp order • Relates model time to physical time at environment interfaces • d0 – sensor latency • Leverages time synchronization across distributed platforms • (IEEE 1588 protocol over Ethernet) • d – comm. latency, ε – sync. error Mixed Simulator HW in the Loop Simulator Plant Model PtidyOS PTIDES Design Workflow Network Model • Steps away from threading model • To ensure event of highest priority is always processed first, interrupts play an important role: • Event processing is done within Interrupt service routines • Reentrant interrupts • No dynamic memory allocation. • Is a library linked against application C code. • Executes PTIDES semantics • Local execution strategy includes a safe to process analysis and resource scheduling layer. • Current implementation uses a Single Stack Event Processing Algorithm Sequence Diagram Comparison Between Synchronous Reactive and PTIDES Implementations *The use of a single stack and interrupts for mutual exclusion was done in TinyOS. PtidyOS uses these concepts and introduces time semantics. Application: The Tunneling Ball Device • Cyber-physical system with real-time constraints • Event-driven signals (motor encoding, object detection) • Parallels an automotive engine control unit (ECU) • Balls drop above a rapidly spinning disc • Device must adjust disc to allow ball to pass through a small hole, without stopping disc BEARS 2010