Content addressable memory (CAM) with error checking and correction (ECC) capability

A content addressable memory (CAM), comprising:

• a plurality of individual CAM cells for storing a codeword, said codeword having a number of bits associated therewith;
• a match line coupled to each of said plurality of individual CAM cells, said match line used to indicate a match status of a comparand word that is compared to said stored codeword, wherein said match status is reflective of either a match state or a mismatch state;
• and
• a sensing apparatus for latching said match line to said match state whenever said comparand word mismatches said stored codeword by a number of N or fewer bits, and said sensing apparatus further latching said match line to said mismatch state whenever said comparand word mismatches said stored codeword by more than N bits, said sensing apparatus further comprising:
• a reference match line, said reference match line being discharged at a selected rate from a precharged state during a compare operation;
• wherein, during said compare operation, said sensing apparatus determines said match status by comparing said selected rate of discharge of said reference match line to a rate of discharge of said match line;
• and
• said CAM cells further being adapted to correct any mismatching bits stored therein if said match line is latched to said match state.

A method for detecting a soft error within a content addressable memory (CAM), the method comprising:

• configuring a plurality of individual CAM cells for storing a codeword having a number of bits associated therewith;
• coupling a match line to each of said Plurality of individual CAM cells, said match line used to indicate a match status of a comparand word that is compared to said stored codeword, wherein said match status is reflective of wither a match state or a mismatch state;
• and
• configuring a sensing apparatus for latching said match line to said match state whenever said comparand word mismatches said stored codeword by a number of N or fewer bits.

A method for detecting and correcting a soft error within a content addressable memory (CAM), the method comprising:

• configuring a plurality of individual CAM cells for storing a codeword having a number of bits associated therewith;
• coupling a match line to each of said plurality of individual CAM cells, said match line used to indicate a match status of a comparand word that is compared to said stored codeword, wherein said match status is reflective of either a match state or a mismatch state;
• configuring a sensing apparatus for latching said match line to said match state whenever said comparand word mismatches said stored codeword by a number of N or fewer bits;
• and
• adapting said CAM cells are adapted to correct any mismatching bits stored therein if said match line is latched to said match state.

A method for detecting and correcting soft error within a content addressable memory (CAM), the method comprising:

• comparing a rate of discharge of a precharged match line included within the CAM with a rate of discharge of a precharged reference match line included within the CAM, said match line being coupled to a plurality of CAM cells within the CAM;
• determining, based on said rate of discharge of said reference match line and said rate of discharge of said match line, whether there exists either a match state or a mismatch state;
• said match state being defined by a mismatch of a N or fewer bits between a stored codeword and a comparand word applied to the CAM;
• said mismatch state being defined by i mismatch of N+1 or more bits between said stored codeword and said comparand word;
• and
• inverting any mismatching bits within said stored codeword if a match state exists.