Implementando uma atualização remota de firmware para sistema embarcado através do protocolo MQTTS

Abstract

Currently, smart devices play a fundamental role in Internet of Things (IoT) environments, being present in various contexts such as homes, offices, stores, and smart cities. In addition to these urban spaces, their application also extends to natural environments, such as forests and oceans, where connected sensors and devices monitor and collect data in real-time. These smart devices rely on communication protocols to interact with each other, allowing for the exchange of information and remote control. These protocols facilitate the manipulation and transmission of data collected by sensors or in response to events, enhancing the operation of connected applications. Among the functionalities enabled is FOTA (Firmware Over the Air), which allows for the remote update of device firmware, ensuring maintenance, bug fixes, and the addition of new features without the need for physical access to the devices, optimizing their performance and security. In this context, this work presents the implementation of a remote firmware update system (FOTA) for the CC1312 microcontroller, using the MQTT communication protocol via AT commands, which are instructions sent to the Cinterion® EXS82 modem to control various communication operations. This work encompasses the development of the microcontroller firmware in the C programming language, an application developed in Python for distributing the image, the connection between them, and the image transfer flow. The solution demonstrated efficiency for blocks of up to 256 bytes; however, it showed failures in CRC calculation for blocks larger than 512 bytes, compromising the integrity of the image. Solutions such as more robust packet fragmentation, retransmission of corrupted packets, and incremental CRC checks are suggested to improve the process.