Patent ID: 7165729

Claim:
An integrated circuit comprising: a first domain including a first communication circuit; a second domain including a second communication circuit operable to communicate with said first communication circuit via a transaction interface using communication transactions in accordance with a transaction protocol; a first state machine operable to move between states indicative of transaction level communication status of said first communication circuit; and a second state machine operable to move between states indicative of transaction level communication status of said second communication circuit; wherein said first domain and said second domain are separately controllable such that at least said second communication circuit may independently move to a state in which said second communication circuit cannot communicate via said transaction interface; and movement between states of said first state machine is at least partly controlled by a current state of said second state machine such if said second communication circuit changes to a state in which said second communication circuit cannot communicate via said transaction interface part way through a pending communication transaction between said first communication circuit and said second communication circuit, then said first state machine makes an associated move between states and said first communication circuit continues processing of said pending communication transaction in accordance with a predetermined default behaviour and in a manner compliant with said transaction protocol.