Patent ID: 9697910
Date: 2017-07-04
CPC Classifications: G11C

Claim:
1. A method of multi-match error detection in content addressable memory (CAM) testing, the method comprising: loading one of a plurality of content addressing rows of a CAM section of a CAM device with a row test address word and remaining content addressing rows of the CAM section with other address values different from the row test address word; loading a plurality of data value rows of a random access memory (RAM) section of the CAM device with unique test patterns in each of the data value rows, each of the unique test patterns having a same number of on-state bits per data value row, and the unique test patterns are formed such that either none of the unique test patterns is equivalent to a logical-OR combination of any two of the unique test patterns or the unique test patterns are formed such that none of the unique test patterns is equivalent to a logical-AND combination of any two of the unique test patterns; initiating a row test to search for a matching content addressing row in the CAM section corresponding to the row test address word; receiving a row test result as one or more data value rows from the RAM section identified as having a content addressing row in the CAM section that matches the row test address word; and determining whether the row test has failed based on comparing the row test result to an aspect of one or more of the unique test patterns.