Bus communications are effected. In accordance with one or more example embodiments, a bus circuit is configured for communicating data in accordance with a main protocol (e.g., as a default), and for communicating with an alternate protocol when signals corresponding to the main protocol are not present. In some implementations, a sense circuit is used with input pins to sense a type of signal for bus communications, and to control communications on the bus with a protocol appropriate for the sensed signals, and for a main protocol when main protocol signals are sensed (e.g., for a default bus operation, or for test operation).