In a near future, energy harvesting is expected to replace batteries in ultra-low-power embedded systems. Research prototypes of such systems have recently been proposed. As the power harvested in the environment is very low, such systems need to cope with frequent power outages. They are referred to as transiently-powered systems (TPS). In order to execute non-trivial applications, TPS need to retain information between power losses. To achieve this goal, emerging nonvolatile memory (NVM) technologies are a key enabler: they provide a lightweight solution to retain, between power outages, the state of an application and of its peripheral devices. These include sensors, serial interface or radio devices for instance. Existing works have described various checkpointing mechanisms to adapt embedded applications to TPS but the use of peripherals was not yet handled. in these works. This paper proposes a solution for embedded applications using any peripheral device to run despite transient power. We follow a kerneloriented approach resulting in minimal impact on the programming model of the application. We implement the new concepts in our lightweight kernel called Sytare, running on an MSP430FR5739 micro-controller and we analyze the cost of the proposed solution.

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Recently has emerged the concept of transientlypowered systems: tiny battery-less embedded systems which harvest energy from their environment. To retain information despite frequent and unpredictable power failures, a transientlypowered system can use non-volatile memory to store checkpoints of program state. However current checkpointing techniques only consider the state of computation (processor, memory) and disregard peripheral state completely. This paper presents a software framework that allows for the use of non-trivial peripherals such as analog-to-digital converters, serial interfaces or radio devices, in transiently-powered systems.