Function Block-Based Robust Firmware Update Technique for Additional Flash-Area/Energy-Consumption Overhead Reduction

Energy consumption and flash-memory usage are very limited in microcontrollers that make up the sensor network, accordingly, the process of updating the embedded firmware should also be low cost and energy efficient. This work proposes a technique that overcomes limitations due to increased costs of configuring the sensor network by additional memory usages and increased energy consumption resulting from firmware updates. Instead of dealing with the whole firmware, we split the firmware into function blocks and managed them with a function map that indicate each function block address. Further, by only updating function blocks where differences exist, we successfully reduced flash memory usage and energy consumption that occurred during the firmware update process. We implemented the proposed technique with the target measurement environment, and the result shows that maximum flash memory usage reduced by 91.4% and that 71.4% reduction in execution time resulted in a 69% reduction in energy consumption over the conventional method.