Operating a state machine includes enabling operation of the state machine upon receiving a signal indicating a change from operation of a test access port to a scan test port. The process maintains the state machine in an IDLE 1 state while receiving a scan test port capture signal and transitions the state machine to an IDLE 2 state when receiving a scan test port shift signal. The process then transitions the state machine to a SEQUENCE 1 state, then to a SEQUENCE 2 state, and then to a SEQUENCE 3 state when receiving sequential scan test port capture signals. The state machine then transitions to an UNLOCK TAP state and then back to the IDLE 1 state when receiving sequential scan test port shift signals on the test mode select/capture select lead.