Fault tolerant TTCAN networks

TTCAN is a time triggered layer using the CAN protocol to communicate in a time triggered fashion. As TTCAN is based on CAN it uses the power of CAN ́s error detection mechanisms and robustness, but it also provides a step towards determinism and time triggered technology. Future system architectures will include applications that need to access more than one TTCAN controller. This article describes how to build fault-tolerant TTCAN networks, in particular the mechanisms to synchronize different TTCAN busses. It is shown that it is very easy to implement a synchronized network of any reasonable redundancy level, even if non-trivial architectures (for instance more than a simple dual channel network) are involved. Moreover, this synchronization can be achieved even when the individual TTCAN busses use different time bases without ever violating the modular integrity of one single bus.