Bidirectional data pin, clock input pin, shift register, debug circuitry
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
Life of this patent
Estimating the term…
Abstract
A two pin communication interface bus and control circuits are used with circuit boards, integrated circuits, or embedded cores within integrated circuits. One pin carries data bi-directionally and address and instruction information from a controller to a selected port. The other pin carries a clock signal from the controller to a target port or ports in or on the desired circuit or circuits. The bus may be used for serial access to circuits where the availability of pins on ICs or terminals on cores is minimal. The bus is used for communication, such as serial communication related to the functional operation of an IC or core design, or serial communication related to test, emulation, debug, and/or trace operations of an IC or core design.
Claims10
An integrated circuit comprising:
- (a) a bidirectional data pin;
- (b) a clock input pin;
- (c) shift register circuitry having a data input coupled to the bidirectional data pin, a data output coupled to the bidirectional data pin, a clock input coupled to the clock input pin, data bit outputs, address bit outputs, and a write bit output;
- and
- (d) a target circuit including:
- (i) a first data register having a first enable input and inputs coupled to the data bit outputs and the write bit output;
- (ii) a second data register having a second enable input and inputs coupled to the data bit outputs and the write bit output;
- and
- (iii) address decode circuitry having inputs coupled to the address bit outputs, and having a first enable output coupled to the first enable input and a second enable output coupled to the second enable input,
- wherein the first data register and the second data register selected by the address bit outputs are operable to be written with the data bit outputs when the write bit output is a first value and to be read when the write bit output is a second value.
Dependencies are inferred from the claim text.