HW/SW co-design of nonvolatile IO system in energy harvesting sensor nodes for optimal data acquisition

Energy harvesting has been widely investigated as a promising alternative for future wearable sensors or internet-of-things. However, power and performance overhead is induced when IO operations are interrupted by power failures because non-preemptive characteristic of IO operations causes expensive re-executions. Furthermore, the state-of-art IO devices need long and power hungry initializing process, which makes IO operations inefficient in transient powered systems. This paper proposed a HW/SW co-design approach for nonvolatile IO system to maximize data acquisition. A ferroelectric flip-flop based nonvolatile IO architecture is adopted to reduce IO initialization overhead by 3-4 orders of magnitude. Based on the nonvolatile IO interface, we further formulate the optimal data acquisition as an INLP problem and a risk-aware online scheduler is presented to solve the problem efficiently. Experimental results show that the proposed HW/SW co-design architecture improves data acquisition by 2-5 times compared with conventional HW/SW architecture.