Method and apparatus for configuring a content-addressable memory (cam) design as binary cam or ternary cam

A computer-implemented method for producing a configurable content-addressable memory (CAM) cell design, said method comprising:

• inputting, to a computer, a configurable CAM cell design, said configurable CAM cell design comprising:
• a first sub-cell design comprising a static random access memory (SRAM)-based ternary CAM cell connected to a first pair of search-lines and a first match-line output;
• and
• a second sub-cell design comprising comparison circuitry connected to a second pair of search-lines and a second match-line output;
• selecting, by using said computer, one of a first metal overlay design and a second metal overlay design to electrically connect said first and second sub-cell designs as one of a binary CAM design including two binary CAM cells with a single search port, and a ternary CAM design including a single ternary CAM cell with two search ports, respectively;
• wherein said first metal overlay design comprises:
• connections between storage data nodes of a first binary CAM cell, and said first match-line output and said second match-line output;
• and
• connections between storage data nodes of a second binary CAM cell, and said first match-line output and said second match-line output;
• and
• wherein said second metal overlay design comprises:
• parallel connections between storage data nodes producing a first ternary CAM cell output and a second ternary CAM cell output, and said first match-line output and said second match-line output, respectively;
• and
• outputting, by said computer, one of said binary CAM design including two binary CAM cells with a single search port, and said ternary CAM cell design including a single ternary CAM cell with two search ports according to said selecting of said first or said second metal overlay design, respectively.

A computer system for producing a configurable content-addressable memory (CAM) design, said system comprising:

• a memory configured to:
• store said configurable CAM cell design, said configurable CAM cell design comprising:
• a first sub-cell design comprising a static random access memory (SRAM)-based ternary CAM cell connected to a first pair of search-lines and a first match-line output;
• and
• a second sub-cell design comprising comparison circuitry connected to a second pair of search-lines and a second match-line output;
• and
• a processor configured to:
• select one of a first metal overlay design and a second metal overlay design to electrically connect said first and second sub-cell designs as one of a binary CAM design including two binary CAM cells with a single search port, and a ternary CAM design including a single ternary CAM cell with two search ports, respectively;
• wherein said first metal overlay comprises:
• connections between storage data nodes of a first binary CAM cell, and said first match-line output and said second match-line output;
• and
• connections between data storage nodes of a second binary CAM cell, and said first match-line output and said second match-line output;
• and
• wherein said second metal overlay comprises:
• parallel connections between storage data nodes producing a first ternary CAM cell output and a second ternary CAM cell output, and said first match-line output and said second match-line output, respectively;
• and
• output one of said binary CAM design including two binary CAM cells with a single search port, and said ternary CAM cell design including a single ternary CAM cell with two search ports according to a selection of said first or said second metal overlay design, respectively.

A computer program storage medium readable by a computer, tangibly embodying a computer program of instructions executable by said computer to perform a method for producing a configurable content-addressable memory (CAM) design, said method comprising:

• inputting a configurable CAM cell design, said configurable CAM cell design comprising:
• a first sub-cell design comprising a static random access memory (SRAM)-based ternary CAM cell connected to a first pair of search-lines and a first match-line output;
• and
• a second sub-cell design comprising comparison circuitry connected to a second pair of search-lines and a second match-line output;
• selecting one of a first metal overlay design and a second metal overlay design to electrically connect said first and second sub-cell designs as one of a binary CAM design including two binary CAM cells with a single search port, and a ternary CAM design including a single ternary CAM cell with two search ports, respectively;
• wherein said first metal overlay design comprises:
• connections between storage data nodes of a first binary CAM cell, and said first match-line output and said second match-line output;
• and
• connections between storage data nodes of a second binary CAM cell, and said first match-line output and said second match-line output;
• and
• wherein said second metal overlay comprises:
• parallel connections between storage data nodes, corresponding to a first ternary CAM cell output and a second ternary CAM cell output, and said first match-line output and said second match-line output, respectively;
• and
• outputting one of said binary CAM design including two binary CAM cells with a single search port, and said ternary CAM cell design including a single ternary CAM cell with two search ports, according to said selecting of said first or said second metal overlay design, respectively.