  Energy-harvesting-powered computing offers intriguing and vast opportunities
to dramatically transform the landscape of the Internet of Things (IoT) devices
by utilizing ambient sources of energy to achieve battery-free computing. In
order to operate within the restricted energy capacity and intermittency
profile, it is proposed to innovate Intermittent Robust Computation (IRC) Unit
as a new duty-cycle-variable computing approach leveraging the non-volatility
inherent in spin-based switching devices. The foundations of IRC will be
advanced from the device-level upwards, by extending a Spin Hall Effect
Magnetic Tunnel Junction (SHE-MTJ) device. The device will then be used to
realize SHE-MTJ Majority/Polymorphic Gate (MG/PG) logic approaches and
libraries. Then a Logic-Embedded Flip-Flop (LE-FF) is developed to realize
rudimentary Boolean logic functions along with an inherent state-holding
capability within a compact footprint. Finally, the NV-Clustering synthesis
procedure and corresponding tool module are proposed to instantiate the LE-FF
library cells within conventional Register Transfer Language (RTL)
specifications. This selectively clusters together logic and NV state-holding
functionality, based on energy and area minimization criteria. It also realizes
middleware-coherent, intermittent computation without checkpointing,
micro-tasking, or software bloat and energy overheads vital to IoT. Simulation
results for various benchmark circuits including ISCAS-89 validate
functionality and power dissipation, area, and delay benefits.
