On-chip Technologies, Inc.

Cadence Design Systems, Inc.

Intellectual Ventures I LLC

Other

Intellitech Corporation

Bulent Dervisoglu

Laurence Hager Cooke

Vacit Arat

Michael Ricchetti

Christopher J Clark

An integrated circuit is described that includes a stored program processor for test and debug of user-definable logic plus external interface between the test/debug circuits and the component pins. The external interface may be via an existing test interface or a separate serial or parallel port. Test and debug circuits may contain scan strings that may be used to observe states in user-definable logic or be used to provide pseudo-random bit sequences to user-definable logic. Test and debug circuits may also contain an on-chip logic analyzer for capturing sequences of logic states in user-definable circuits. Test and debug circuits may be designed to observe states in user-definable circuits during the normal system operation of said user-definable circuits.

On-chip service processor

Addition of specific test logic may improve the level of test vector compression achieved from existing variable scan test logic. Methods for determining the compressed vectors' states, given the desired uncompressed vectors' values may be used, and techniques for selectively enabling test or other features on a chip by inserting the proper code or codes into the chip may further be used. Techniques may be used to incorporate and apply various types of reset operations to multiple strings of variable scan test logic, as may methods to minimize the test vector compression computation time.

Variable clocked scan test improvements

An architecture and methodology for test data compression using combinational functions to provide serial coupling between consecutive segments of a scan-chain are described. Compressed serial-scan sequences are derived starting from scan state identifying desired Care_In values and using symbolic computations iteratively in order to determine the necessary previous scan-chain state until computed previous scan-chain state matches given known starting scan-chain state. A novel design for a new flip-flop is also presented that allows implementing scan-chains that can be easily started and stopped without requiring an additional control signal. Extensions of the architecture and methodology are discussed to handle unknown (X) values in scan-chains, proper clocking of compressed data into multiple scan-chains, the use of a data-spreading network and the use of a pseudo-random signal generator to feed the segmented scan-chains in order to implement Built In Self Test (BIST).

Accelerated scan circuitry and method for reducing scan test data volume and execution time

A system and method for testing an integrated circuit having internal circuit blocks. Each of the internal circuit blocks may have its own test circuit block, referred to as a socket access port. The integrated circuit preferably includes a chip access port (e.g., an IEEE standard 1149.1 compliant test access port) connected to a set of boundary-scan cells, and connected in a hierarchical fashion to the lower-level test circuit blocks. Each of the lower-level test control circuit blocks preferably comprises a socket access port controller, and test operation is transferred downward and upwards within said hierarchical structure by communicating from a test control circuit block to the test control circuit block at the immediately higher or immediately lower level in the hierarchical structure. Each of the lower-level test control circuit blocks of the hierarchical test control network may be functionally identical. Further, each of the lower-level test control circuit blocks may be structurally identical. An existing boundary scan may be easily modified for use in the hierarchical structure by adding push instructions to send it to a lower-level test circuit block, and pop instructions to return control to the higher level test circuit block.

Hierarchical test circuit structure for chips with multiple circuit blocks

An integrated circuit is described which include a stored program processor for test and debug of user-definable logic plus external interface between the test/debug circuits and the component pins. The external interface may be via an existing test interface, or a separate serial or parallel port. Test and debug circuits may contain scan strings that may be used to observe states in user-definable logic or be used to provide pseudo-random bit sequences to user-definable logic. Test and debug circuits may also contain on-chip logic analyzer for capturing sequences of logic states in user-definable circuits. Test and debug circuits may be designed to observe states in user-definable circuits during the normal system operation of said user-definable circuits.

A hierarchical test control network for an integrated circuit includes a top-level test control circuit block having a chip access port (CAP) controller. The hierarchical test control network also has multiple lower-level test control circuit blocks connected to the top-level test control circuit block in a hierarchical structure. Each of the lower-level test control circuit blocks are a socket access port (SAP) controller. Test operation is transferred downward and upwards within said hierarchical structure.

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Mountain View, CA, United States of America

Bulent Dervisoglu