Lock state machine operations upon stp data captures and shifts
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
Life of this patent
Estimating the term…
Abstract
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.
Claims3
A process of operating a state machine comprising:
- A. enabling operation of the state machine upon receiving an enabling signal indicating a change from operation of a test access port to a scan test port;
- B. maintaining an IDLE 1 state while receiving scan test port capture signals on a test mode select/capture select lead;
- C. transitioning from the IDLE 1 state to an IDLE 2 state when receiving a scan test port shift signal on the test mode select/capture select lead;
- D. maintaining the IDLE 2 state when receiving a scan test port capture signal on the test mode select/capture select lead;
- E. transitioning from the IDLE 2 state to a SEQUENCE 1 state when receiving a scan test port capture signal on the test mode select/capture select lead;
- and
- F. transitioning from the SEQUENCE 1 state to the IDLE 2 state when receiving a scan test port shift signal on the test mode select/capture select lead.
Dependencies are inferred from the claim text.