Texas Instruments Corporation

Mudasir Shafat Kawoosa

Rajesh Kumar Mittal

Sreenath Narayanan Potty

Vishal Diwan

Vivek Singhal

Prateek Giri

Rubin Ajit Parekhji

Pervez Garg

A device includes a scan chain including a plurality of storage elements and an output buffer; a shadow shift register having a shadow shift input coupled to a scan output of one of the storage elements of the scan chain; a signature register; and a comparator having a first input, a second input, and an output. The comparator first input is to receive a value of the shadow shift register, and the comparator second input is to receive a value of the signature register. The output buffer has a control input coupled to the comparator output, and the output buffer provides a high-impedance output responsive to the value of the shadow shift register being unequal to the value of the signature register.

Secured scan access for a device including a scan chain

A scan chain may be formed throughout an integrated circuit in which the scan chain is coupled to a set of pins via bi-directional input/output (I/O) buffers. A state machine may be provided to control the scan chain. Decoding logic may monitor states and transitions between states and generate pseudo static control signals in response to certain states and transition sequences in order to free up test pins for use as additional scan data I/O pins using a single JTAG IR. A test pattern may be received from an external tester using the set of I/O pins and buffers operating in parallel. The test pattern may then be provided to combinatorial logic circuitry coupled to the scan chain. A response pattern may be captured in the scan chain. The response pattern may then be provided to the external tester using the same set of I/O pins and buffers operating in parallel.

Generating multiple pseudo static control signals using on-chip JTAG state machine

An integrated circuit (IC) includes logic components and a scan test circuit coupled to the logic components. The IC also includes a scan input pin coupled to the scan test circuit. The IC also includes a scan input/output pin coupled to the scan test circuit. The scan test circuit includes a decoder coupled to at least one of the scan input pin and the scan input/output pin. The decoder includes storage elements configured to store different scan control signals and to output at least one of the different scan control signals in response to a master control signal.

Scan test control decoder with storage elements for use within integrated circuit (IC) devices having limited test interface

A scan chain may be formed throughout an integrated circuit in which the scan chain is coupled to a set of pins via bi-directional input/output (I/O) buffers. A test pattern may be received from an external tester using the set of I/O pins and buffers operating in parallel. The test pattern is scanned into the scan chain using a shift clock operating at a first rate. The test pattern is then provided to combinatorial logic circuitry coupled to the scan chain. A response pattern is captured in the scan chain and then scanned from the scan chain using a shift clock operating at a second rate that is slower than the first rate. The response pattern is provided to the external tester using the same set of I/O pins and buffers operating in parallel.

Non-interleaved scan operation for achieving higher scan throughput in presence of slower scan outputs

A method of testing a device under test, the device under test comprising a scan chain having a number of storage elements. The method determines a representation of toggling events in a test sequence, where the test sequence is for testing the scan chain. The method also selectively times input of a bit sequence, corresponding to the test sequence, to a first storage element in the number of storage elements, and through the scan chain, in response to the determining step.

Dynamically protective scan data control

An embodiment provides a circuit for testing an integrated circuit. The circuit includes an input converter that receives N scan inputs and generates M pseudo scan inputs, where M and N are integers. A scan compression architecture is coupled to the input converter and generates P pseudo scan outputs in response to the M pseudo scan inputs. An output converter is coupled to the scan compression architecture and generates Q scan outputs in response to the P pseudo scan outputs, wherein P and Q are integers. The input converter receives the N scan inputs at a first frequency and generates the M pseudo scan inputs at a second frequency and the output converter receives the P pseudo scan outputs at the second frequency and generates the Q scan outputs at the first frequency.

Method and apparatus for test time reduction using fractional data packing

An integrated circuit with functional circuitry and testing circuitry, the testing circuitry having a state machine operable in a plurality of different states. The integrated circuit also has a pin for receiving a signal, wherein the state machine is operable to transition between states in response to a change in level of the signal. Circuitry couples the signal of the pin, in a first level, to the state machine in a first time period for causing the state machine to enter a predetermined state, and circuitry maintains the signal in the first level to the state machine in a second time period for maintaining the state machine in the predetermined state. Also during the second time period, circuitry couples data received at the pin to a destination circuit other than the state machine, wherein the destination circuit is operable to perform plural successive scan tests using data from the pin without a power on reset of the functional circuitry.

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Srinagar, India

Mudasir Shafat Kawoosa