Optimizing Master-Slave Broadcast Communication in Multi-Node Network Using RS485 Standard

This paper presents a comprehensive study on implementing master-slave Broadcast Communication over a differential signaling standard (RS-485) that defines the electrical interface and physical layer for connecting electrical devices. The focus is on designing and timing analysis of a communication system involving multiple STM32 microcontrollers arranged in a daisy chain configuration. The master device broadcasts commands to multiple slave devices, which, after receiving the commands, sends feedback to the master as well as other slaves. The system uses Direct Memory Access (DMA) for efficient data transfer, Cyclic Redundancy Check (CRC) for error detection, and precise timing control to ensure reliable communication. A key feature of this system is its unique feedback mechanism, where all nodes receive data and execute commands, but only the addressed node provides feedback. Multiple nodes then accept this feedback, ensuring synchronized operation and real-time updates across the network. This study highlights implementing a communication system in a project involving a master-slave configuration, where the master node initiates communication, processes feedback, and adjusts timing. The system has been rigorously tested on a Remotely Operated Vehicle (ROV) with a 6-degree of Freedom (DOF) arm and differential drive, demonstrating its reliability and efficiency in controlling complex robotic movements and feedback mechanisms.