Abstract: A bus in an integrated circuit uses bus interfaces to couple functional blocks to the bus in a processor independent and scalable manner. Various embodiments of the bus interfaces include a bus interface for a bus master functional block, a bus interface for a slave functional block, and a bus interface for either a bus master functional block or a slave functional block. Each bus interface includes a state machine that has at least two operational modes including a fast operational mode having two states and a normal operational mode having at least four states. A bus interface coupled to a bus master functional block implements an operational mode and a bus interface coupled to a slave functional block operates in a complementary operational mode. Each bus interface is also equipped to facilitate scaling of the address and/or data width on the bus.