One-transistor-cell 4-valued universal-literal CAM for cellular logic image processing

A non-volatile 4-valued content-addressable memory (CAM) is proposed for fully parallel template-matching operations in real-time cellular logic image processing with fixed templates. A universal literal in each CAM cell is used to compare a 4-valued input pixel with a 4-valued template pattern. Any CAM cell functions are performed by a pair of a simple threshold operation and a logic-value conversion which is shared by CAM cells in the same column of a CAM cellular array. Moreover, the use of a single floating-gate MOS transistor makes it possible to implement a universal-literal circuit together with a 4-valued storage element. As a result, a high-density 4-valued universal-literal CAM, with a single transistor cell is designed by using a multi-layer interconnection technology. Its performance is much superior to that of conventional CAM-based implementations under the same dynamic power dissipation.