wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

43
Protocols of the
Time-Triggered
Architecture: TTP,
TTEthernet, TTP/A
Wilfried Elmenreich
University of Klagenfurt
Christian
El-Salloum
Vienna University
of Technology
43.1 Introduction.....................................................................................43-1
43.2 The Time-Triggered Paradigm......................................................43-2
Sparse Time. •. Flow Control and Temporal Firewall
43.3 Time-Triggered Communication..................................................43-3
43.4 Time-Triggered Protocol (TTP)....................................................43-4
Fault Hypothesis and Fault Handling. •. Fault Tolerance. •. .
Membership
43.5 Time-Triggered Ethernet................................................................43-5
Principles of Operation. •. Time Format. •. Periods. •. Fault-Tolerant
TTEthernet Configuration. •. Clock Synchronization
43.6 TTP/A................................................................................................43-7
Interface File System. •. The Three Interfaces of a Smart
Transducer. •. Principles of Operation
Acknowledgments.................................................................................... 43-11
References.................................................................................................. 43-11
43.1 Introduction
Time-triggered systems derive control by the progression of time and thus use the concept of time in
the problem statement as well as in the provided solution. This approach supports a specification of
interfaces including the temporal domain (e.g., send and receive instants of messages) and the implementation
of “temporal firewalls,” which prevent error propagation via control signals. Time-triggered
systems support membership identification, interoperability, and replica determinism.
The concepts of time-triggered systems have been composed in the time-triggered architecture [KB03],
establishing a framework for the implementation of dependable distributed real-time embedded applications.
Besides protocols that employ a time-triggered scheduling like Flexray [Fle05] and TT-CAN
[HMFH00], there exist three protocols that are especially designed according to the time-triggered
architecture: time-triggered protocol (TTP), time-triggered Ethernet (TTEthernet), and TTP for SAE
Class A [SAE95a] applications (TTP/A).
The TTP (also known as TTP/C protocol since it suites SAE class C application requirements
[SAE95b]) provides a highly dependable real-time communication service with a fault-tolerant clock
synchronization and membership service. TTP is suitable for X-by-wire systems in the automotive and
avionics domain.
43-1
© 2011 by Taylor and Francis Group, LLC