The major components of the TTP bus are the instances of controller model shown in figure 3. The current protocol state is managed by the FSM 'ControllerStates' shown below. Possible states are Freeze, Init, Listen, Passive, Active, and ColdStart.
After node initialization the controller sends cold start frames or listen for received cold start frames or TTP frames (in this implementation all frames contain explicit CStates) to integrates on it. During this cluster startup the 'SlotManager' starts the timing according to the defined TDMA layout. It triggers the 'ControllerStates' model at the begin of receiving or sending slots and at the end of transmission phase. After cluster start has finished the controller can send and receive TTP frames. When 'ControllerStates' is triggered at port 'InATSender' clique avoidance and communication blackout tests are requested to model 'Membership & Acknowledgment'. If one of the checks fails, the controller freezes. In other case if the controller is in active state the'Sender' model creates a TTP frame which contains the CNI frame stored in the input buffer memory and send it over module 'Membership & Acknowledgment' to the TTP/C bus. When the model 'Receiver' is triggered at port 'ActionTimer' it listen on TTP/C channel until receiving trigger on input port 'EndOfTP'. After this the module checks the received frame for transmission errors and failures and send the frame to 'Membership & Acknowledgment' for CState agreement test. At the same time membership & acknowledgment services are performed. The CNI (Communication Network Interface) is realized by the ports 'Ack', 'COFlag', 'ControllerError', 'FromHost', and 'ToHost'. 'FromHost' and 'ToHost' offer the frame communication between controller and host. 'Ack' is fired by the controller if the decision phase for acknowledgment of the last sent frame has finished. An observed controller error (clique error, communication blackout, maximum acknowledgment failurre) is sent to host over port 'ControllerError'. The host can restart or freeze the controller by firing the 'COFlag' port.