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US 9,958,503 B2Granted
Tap SPC with tap state machine reset and clock control
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
Life of this patent
Estimating the term…
Abstract
An optimized JTAG interface is used to access JTAG Tap Domains within an integrated circuit. The interface requires fewer pins than the conventional JTAG interface and is thus more applicable than conventional JTAG interfaces on an integrated circuit where the availability of pins is limited. The interface may be used for a variety of serial communication operations such as, but not limited to, serial communication related integrated circuit test, emulation, debug, and/or trace operations.
Claims5
An integrated circuit, comprising:
- A. tap domain test access port circuitry having a test data in (TDI) input lead, a test mode select (TMS) input lead, a test clock (TCK) input lead, and a test data out (TDO) output lead;
- and
- B. serial to parallel control circuitry having a data I/O (DIO) lead and a clock (CLK) input lead, the serial to parallel control circuitry having a TDI output lead coupled to the TDI input lead, a TMS output lead coupled to the TMS input lead, a TCK output lead coupled to the CLK input lead, and a TDO input lead coupled to the TDO output lead, the serial to parallel control circuitry including:
- i. serial input parallel output circuitry having a serial input connected to the data I/O DIO lead, a clock input connected with the clock input lead, a TDI output, and a TMS output;
- ii. update register circuitry having a first input connected to the TDI output of the serial input parallel output circuitry and a first output connected to the TDI output lead, having a second input connected to the TMS output of the serial input parallel output circuitry and a second output connected to the TMS output lead, and having an update clock (UCK) input;
- iii. tap state machine circuitry separate from the tap domain test access port circuitry, the tap state machine circuitry having a TCK input connected to the TCK output lead, a TMS input connected to the TMS output lead, and a reset output, the tap state machine circuitry being free of connections to the tap domain test access port circuitry;
- and
- iv. clock controller circuitry having an input connected to the CLK clock input lead, an update clock UCK output connected to the update UCK clock input, a test clock output lead connected to the TCK output lead, and a reset input connected to the reset output.
5 more elements
Dependencies are inferred from the claim text.