An area-efficient microcontroller with an instruction-cache transformable to an ambient temperature sensor and a physically unclonable function

This paper presents a novel microcontroller-system-onchip (μC-SoC) for pervasive sensing systems, with a 6T SRAM instruction cache dynamically transformable to an ambient temperature sensor and physically unclonable function (PUF). As those sensing and PUF operations are performed in a duty-cycled manner in targeted systems, the proposed transformation can save silicon area, e.g., by ~9.8X as compared to dedicated sensor and PUF circuits that achieve comparable robustness with our temperature sensor and PUF. Specifically, the temperature sensor achieves -0.5/+1.5°C error with one-point calibration and 0.46°C/100mV power supply sensitivity; the PUF passes applicable NIST tests, achieves 0.97% unstable bits and 0.62% BER with TMV and comparator-input-swapping.