Abstract: Aspects of a method and system of using a single EJTAG interface for multiple TAP controllers may comprise communicating information to a plurality of debugging interfaces, the method comprising simultaneously broadcasting a single debug message to a plurality of TAP controllers where the debug message is received via a single debug interface. The method may further comprise simultaneously broadcasting the single debug message to selected ones of a plurality of TAP controllers. An input enable register control signal may be generated that selects which, of a plurality of TAP controllers, is to receive the debug message. The single debug interface may be a JTAG interface which is capable of receiving and sending JTAG messages, or EJTAG messages.