Event-triggered communication on top of time-triggered architecture

The time-triggered architecture is a distributed architecture for high-dependability real-time systems such as avionics systems, engine controls or brake-by-wire systems in the automotive domain. The core element of the architecture is the time-triggered communication protocol TTP. TTP uses a time-triggered medium access control strategy, which makes it fully composable in the time and value domain. TTP usually transmits real-time, state data, with small latency and minimal latency jitter. But is also possible to transmit event data over a dedicated event channel. This paper demonstrates how an application can transmit safety-critical real-time data together with non-critical event data and explains the advantages over conventional event-triggered communication systems. The author introduces a generic approach for event-data transmission that makes it possible to layer other protocols such as MIL-STD-1553, CAN or TCP/IP on top of TTP.