Associative memory capable of searching for data while keeping high data reliability

Abstract

A CAM unit has a memory array for storing storage data, and a RAM unit has a memory array for storing the same storage data and check bits added thereto for determining whether the storage data in its memory array has an error. An error correction circuit uses the check bits to correct any error of data read from the memory array of the RAM unit and rewrite the error-corrected data to the memory arrays. Even if a soft error occurs in the storage data, the check bits can be used to correct the error in the data and rewrite the error-corrected data. Thus, a matching comparison can be performed on the storage data with high reliability.

1 . A semiconductor device comprising: 
 a first memory unit including a plurality of memory cell rows that store data for performing a matching comparison between input search data and storage data stored in advance correspondingly to each memory cell row;    a second memory unit storing, correspondingly to each memory cell row, information that is corresponding to said storage data stored in said first memory unit and check data used for checking said storage data; and    a control unit determining whether said storage data has a error based on said check data stored in said second memory unit and correcting said storage data stored in said first memory unit.    
     
     
         2 . The semiconductor device according to  claim 1 , 
 wherein said a control unit includes a check bit addition circuit which adds said check data to a corrected storage data as said write data and outputs said write data to said second memory unit.