A multi-functional memory unit with PLA-based reconfigurable decoder

An application-specific usage of memory is an important key in development of embedded systems for IoT devices. A functional memory unit such as content addressable memory (CAM) is a good solution for network-specific applications. This work proposes a novel functional memory unit which can reconfigure a function of the memory decoder. In our reconfigurable mechanism, uni-switch cells are introduced to play an alternative role of a logic or a wire, and are embedded in an SRAM memory array. A set of uni-switches is connected and constitutes a programmable logic array (PLA) unit. The PLA has a suitable advantage for a decoder that the multi-input and multi-output function can be realized with a small area, compared with look-up table (LUT). Hence, an extensional function of the decoder is realized by PLA units inside the memory array, and a combination of PLA units provides potentials to configure various functions for stored data such as sorting, filtering, error correction, and encryption/decryption. In this paper, we present a fundamental architecture of our functional memory unit with PLA units, and demonstrate an implementation of 32-bit full adder and 2-bit counter by using PLA units.