International Business Machines Corporation

Synopsys, Inc.

Thomas B Chadwick, Jr

Michael Richard Ouellette

Nancy H Pratt

Rahul K Nadkarni

David James Hathaway

Douglas Willard Stout

Ivan L Wemple

Jeremy Paul Rowland

Margaret R Charlebois

Jason Edward Rotella

Tarl S Gordon

Eric Jasinski

Robert Dov Herzl

Kenneth Anthony Lauricella

Arnold S Tran

Michael Richard Quellette

Tari S Gordon

An integrated circuit (IC) may include a memory device and a circuit coupled with the memory device. The circuit may precondition the memory device to sustain oscillations, initiate first oscillations in a first loop that includes the memory device, and initiate second oscillations in a second loop that does not include the memory device.

On-chip automation of clock-to-Q access time measurement of a memory device

Methods and systems for enumerating digital circuits in a system-on-a-chip (SOC) are disclosed. The method includes incrementing an enumeration value received from a previous enumerable instance to uniquely identify an immediately adjacent enumerable instance of a plurality of enumerable instances in a daisy chain configuration.

Method and system for enumerating digital circuits in a system-on-a-chip (SOC)

A cache for use in a central processing unit (CPU) of a computer includes a data array; a tag array configured to hold a list of addresses corresponding to each data entry held in the data array; a least recently used (LRU) array configured to hold data indicating least recently used data entries in the data array; a line fill buffer configured to receive data from an address in main memory that is located external to the cache in the event of a cache miss; and a shadow register associated with the line fill buffer, wherein the shadow register is configured to hold LRU data indicating a current state of the LRU array.

Shadow registers for least recently used data in cache

A method, system and computer program product for analyzing and modifying a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit (IC) with a transient power supply are disclosed. A static timing slack analysis is performed at a selected endpoint in an IC to obtain a candidate timing path leading to the endpoint with a worst static timing slack. A transient static timing slack is determined for the candidate timing path for each clock cycle of a clock signal under the transient power supply. The determined transient static timing slack is used to adjust the timing of the IC and to modify the static timing slack of the candidate timing path.

Static timing slacks analysis and modification

A local word-line redundancy architecture and method that implements both word-line and match-line steering for semiconductor memories and more particularly for content-addressable memories (CAM) are introduced. According to the present invention, the method of performing local word-line redundancy comprising: testing by using BIST, storing results, comparing failing read address data and failing match-line address data to determine if redundancy is possible and, if so, storing the redundancy repair data pattern and loading that patten upon initialization so that redundancy steering is activated.

Method and apparatus of local word-line redundancy in CAM

A method and structure for improving a content addressable memory array has a plurality of serially connected memory sub-arrays (which include at least one memory cell), a matchline connected to each of the sub-arrays, a valid memory cell, a comparator receiving input from the matchline and valid memory cell, a sinkline output from the comparator, and a precharge device. The sinkline and matchline are reset from a first voltage to a second voltage depending upon the results of a compare operation of the input data to the data in the storage device. When the second voltage appears on the matchline and the first voltage appears on the sinkline this indicates a match between the data within all of the sub-arrays and the input data.

Saving content addressable memory power through conditional comparisons

A method and structure for content addressable memory structure having a memory array of words, each word having multiple memory bits and a plurality of matchlines. Each of the matchlines is connected to one of the words and a matchline compare circuit is connected to the matchlines and is adapted to test all of the words individually. The matchline compare circuit includes a plurality of comparators equal in number to a number of the words, such that each word is connected to a dedicated comparator to allow each word in the memory array to be individually tested.

Embedded CAM test structure for fully testing all matchlines

A content addressable memory device comprises a NAND-NOR chain comprised an alternating sequence of NAND and NOR stages; the NAND stages, each including a first CAM cell comprising a first memory cell that stores a first data bit and a first compare cell that compares the first data bit with a first compare bit and generates a first compare signal indicating whether the first data bit matches the first compare bit and a logical NAND gate that combines the first compare signals of other first CAM cells in the NAND stage; the NOR stages, each including a second CAM cell comprising a second memory cell that stores a second data bit and a second compare cell that compares the second data bit with a second compare bit and generates a second compare signal indicating whether the second data bit matches the second compare bit and a logical NOR gate that combines the second compare signals of other second CAM cells in the NOR stage; and the NAND-NOR chain generating a match signal indicating a match of all the compare bits to all the data bits in the content addressable memory device.

Growing community of inventors

Essex Junction, VT, United States of America

Thomas B Chadwick, Jr