Commanded jtag test access port operations
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
Life of this patent
Estimating the term…
Abstract
The disclosure describes a novel method and apparatus for improving the operation of a TAP architecture in a device through the use of Command signal inputs to the TAP architecture. In response to a Command signal input, the TAP architecture can perform streamlined and uninterrupted Update, Capture and Shift operation cycles to a target circuit in the device or streamlined and uninterrupted capture and shift operation cycles to a target circuit in the device. The Command signals can be input to the TAP architecture via the devices dedicated TMS or TDI inputs or via a separate CMD input to the device.
Claims20
A device comprising:
- a test clock (TCK) input;
- a test mode select (TMS) input;
- a test data in (TDI) input;
- a test data out (TDO) output;
- an instruction register coupled to the TDI input and to the TDO output;
- a command circuit coupled to the TCK input and to the TMS input;
- a first routing circuit coupled to the instruction register and to the command circuit;
- and
- a first data register coupled to the first routing circuit.
A system comprising:
- a daisy chain of devices including a first device and a second device;
- a clock input coupled to the first device and to the second device;
- a test clock (TCK) input coupled to the first device and to the second device;
- a test mode select (TMS) input coupled to the first device and to the second device;
- wherein the first device includes:
- an instruction register;
- a command circuit coupled to the TCK input and to the TMS input;
- a first routing circuit coupled to the instruction register and to the command circuit;
- and
- a first data register coupled to the first routing circuit.
Dependencies are inferred from the claim text.