Abstract: An apparatus and method for generating a comparand in a content addressable memory array. For one embodiment, the apparatus includes a content addressable memory (CAM) array and translation circuitry. The CAM array receives a comparand and the translation circuitry includes at least one first input, at least one second input, and at least one output. The first input is configured to receive an input data having a plurality of bit groups, wherein a first bit group has a first position in the input data relative to other bit groups. The second input is configured to receive translation information indicative of translation of the first bit group from the first position to a different position in a comparand. The output is coupled to the CAM array to transmit the comparand to the CAM array. For one example, the translation circuitry includes a switch circuit that may include one or more multiplexers or demultiplexers.

Abstract: A content addressable memory (CAM) (200) is disclosed that includes a value match mode, where a comparand value can be compared to a masked data value, and a range match mode where a comparand value can be compared to an upper range limit UR and a lower range limit LR. The CAM (200) may include a number of CAM cells (204-n to 204-0) that may each be connected to a compare section (109). A compare section (109) can include a first compare circuit (210) that may generate a match indication on a match line (212) and a second compare circuits (214-n to 214-0). A more significant second compare circuits (214-n) may provide upper and lower limit match results (UMn, LMn) to a less significant first compare circuit (210).

Abstract: A content addressable memory (CAM) device having a memory, a hash index generator to associate a search value with a unique location within a memory, and a compare circuit. The index generator generates an index based on the search value. The memory receives the index from the index generator and outputs a stored data value from a location indicated by the index. A compare circuit receives the data value from the memory and compares the data value and the search value to generate a match signal indicative of whether the data value and search value match. The match signal and index are output from the CAM device.

Abstract: A CAM device having internal circuitry to reduce test time through parallel test setup and parallel pass/fail result generation. A plurality of match results is generated in parallel within a plurality of CAM blocks of the CAM device in response to a search instruction, each match result including a block flag signal that indicates whether a match was detected within a corresponding one of the CAM blocks and a block index that indicates a location of an entry within the one of the CAM blocks. The block index and block flag signal of a highest priority one of the match results is output from the CAM device if an operating mode value indicates a first operating mode, and the block flag signals of the plurality of match results is output from the CAM device if the operating mode value indicates a test operating mode.

Abstract: According to one embodiment, a content addressable memory (CAM) device (100) may include a number of CAM entry sets (102-0 and 102-1), each of which includes multiple CAM entries. CAM (100) may also include multiple programmable information registers (PIRs) (104-0 and 104-1), each of which can be associated with a CAM entry set (102-0 and 102-1). PIRs (104-0 and 104-1) may be accessed in response to CAM commands. Values stores in PIRs (104-0 and 104-1) may control access to associated CAM entry sets (102-0 and 102-1) and/or be output in response to predetermined operations in an associated CAM entry set (102-0 and 102-1).

Abstract: A method of operation within a content addressable memory (CAM) device. An input data word having a plurality of data bits and a plurality of mask bits is received in the CAM device. An encoded data word is generated based, at least in part, on states of the mask bits within the input data word. A write data word is selected from a group of data words that includes at least the input data word and the encoded data word. The write data word is stored within a row of CAM cells within the CAM device.

Abstract: A ternary content addressable memory (TCAM) cell (100) can include two memory elements (102-0 and 102-1) with a single bit line (106-0 and 106-1) per memory element. A TCAM cell (100) can also include a compare stack (104) and two word lines (114 and 116) that can connect to each memory element (102-0 and 102-1). The memory elements (102-0 and 102-1) can include SRAM type memory cells with one of two data terminals connected to a pre-write potential (Vpre, which can be a ground potential, or the like). Write operations can include pre-setting the data values of memory elements (102-0 and 102-1) to the pre-write potential prior to providing write data via the bit lines (106-0 and 106-1).

Abstract: According to one embodiment of the present invention, a content addressable memory (CAM) device includes a CAM array that includes a plurality of rows of CAM cells each coupled to a corresponding match line, and a test circuit coupled to the match lines that outputs row match results from the match lines onto a match output.

Abstract: A bit line control circuit is coupled between a bit line of an associated Content Addressable Memory (CAM) Array and a supply voltage. The bit line control circuit adjusts the charge current for the bit line in response to a bit line control signal. For some embodiments, the bit line control circuit includes a dynamic component and a static component to control the bit line.

Abstract: A content addressable memory (CAM) device (200) can include a control block (202) having a dummy control circuit (216). A dummy control circuit (216) can initiate dummy searches (or other operations) prior to and/or during actual searches to reduce overall supply current transients. Methods for initiating dummy searches are also disclosed.

Abstract: A method and apparatus for performing packet classification in a digital signal processor for policy-based packet routing. For one embodiment, the digital signal processor includes a policy statement table for storing policy statements. Each policy statement has associated with it a priority number that indicates the priority of the policy statement relative to other policy statements. The priority numbers are separately stored in a priority index table. The priority index table includes priority logic that determines the most significant priority number from among the policy statements that match an incoming packet during a classification of filter operation. The priority logic also identifies the location in the priority index table of the most significant priority number. The identified location in the priority index table can be used to access associated route information or other information stored in a route memory array.

Abstract: A low power content addressable memory (CAM) device. The CAM device receives an N-bit comparand value and, in response, activates less than N compare lines within the CAM device to compare each of the N bits of the comparand value with contents of CAM cells coupled to the N compare lines.

Abstract: A content addressable memory (CAM) device (200) can equalize a potential between a match line (202) and corresponding pseudo-supply (PVSS) line (204) in a pre-sense operation. In a sense operation, a sensing device (P4) can determine a match condition exists when the match line (202) potential varies from the PVSS line (204) potential. Complementary compare data lines (CD and BCD) can be equalized with one another in a pre-sense operation, while one compare data line (CD or BCD) can be equalized with bit lines (BB1 and/or BB2) in the sensing operation.

Abstract: A memory/logic cell layout structure includes a pair of memory/logic cells formed on a substrate. Each memory/logic cell (102, 104) can include a pair of memory areas to store data (106-0/106-1, 106-2/106-3), and a logic portion (108-0, 108-1) that receives the data stored therein. Memory areas and the logic portions of each memory/logic cell can be arranged on the substrate in a shape of an L, U, S, T, or Z to form a pair of interlocking memory/logic cells.

Abstract: A search engine system (100) and CAM device (300) are disclosed. A search engine system (100) may generate response packets (112) in response to requests packets (110) and include at least one content addressable memory (CAM) device (102-0) having an input interface (116-0) for receiving data packets and an output interface (116-1) for transmitting data packets.

Abstract: A content addressable memory (CAM) device includes a CAM array and a configuration circuit. The CAM array has a plurality of rows of CAM cells, each row segmented into a plurality of row segments, each row segment including a plurality of CAM cells coupled to a corresponding match line segment, and a match line control circuit having an input coupled to the corresponding match line segment, an output coupled to the match line segment in a next row segment, and a control terminal to receive a corresponding enable signal. The configuration circuit has an input to receive configuration information indicative of a width and depth configuration of the CAM array and having outputs to generate the enable signals.

Abstract: A digital signal processor. The digital signal processor includes a content addressable memory (CAM) array for storing entries. The digital signal processor includes a partitioned priority index table having a plurality of rows and columns of priority blocks. Each row of the plurality of rows of priority blocks is capable of storing a priority number associated with an entry in the CAM array. Each column of the plurality of columns of priority blocks has compare logic coupled to each of the priority blocks in its respective column. The digital signal processor includes an encoder coupled to the partitioned priority index table.

Abstract: A digital signal processor. The digital signal processor includes a first data classification block. The first data classification block outputs a first block priority number associated with a first data stored in the first data classification block that matches a search key. The digital signal processor includes a second data classification block. The second data classification block outputs a second priority number associated with a second data stored in the second data classification block that matches the search key. The digital signal processor includes a device index processor. The device index processor selects a most significant block priority number from the first block priority number and the second block priority number.

Abstract: A content addressable memory includes a priority encoder that is in communication with an array of the content addressable memory cells to receive match signals, and from the match signals generating an output index signal in accordance with a priority sequence of the match signals. The priority encoder has a plurality of input circuits to receive the match signals from the CAM array. A priority setting circuit receives a priority transformation signal indicating a priority index for modification of the priority sequence. An encoding circuit is in communication with the plurality of input circuits and the priority setting circuit for generating the output index signal in accordance with the priority sequence. The priority encoder circuit further includes an enabling circuit for receiving an enabling signal.

Abstract: A content addressable memory (CAM) device (400) can sequentially apply command and key data to different sections (404-1 to 404-4). Within each section, CAM cores (402-11 to 402-44) can be sequentially activated. Current surges when transitioning from an idle state to an active state, or vice versa, can be significantly reduced with additional latency but no loss in throughput.