In-vehicle communication systems

The rapid transformation of the automotive industry through electrification, digitalization, and autonomous systems has increased both the complexity of in-vehicle communication infrastructure and the need for flexibility. Numerous sensors, actuators, and control units in various vehicle brands and models must operate in an integrated manner using different communication protocols such as CAN, CAN FD, LIN, RS485, UART, I2C, and SPI. This diversity often makes the integration of new hardware or external modules, especially in aftermarket applications, challenging and costly.In this thesis, a modular and universal communication module supporting multiple protocols was designed and tested on a real application scenario. The developed system was configured to transmit data received from any external sensor, actuator, or electronic unit directly to the vehicle's ECU and an external display without any additional hardware intervention. The hardware of the module utilizes an STM32-based ARM microcontroller, while the software automatically decodes and interprets incoming data under a unified protocol structure and converts it to the required protocol for the target systems.The system supports all protocols such as CAN, CAN FD, CAN 2.0A/B, RS485, LIN, UART, I2C, and SPI, both in hardware and software. Moreover, thanks to the proposed modular architecture, there is no need for additional software or hardware development in protocol conversion. As a result, aftermarket hardware integration processes have been accelerated, costs have been reduced, and flexibility has been maximized.The developed protocol is among the first of its kind in the scientific literature and serves as an important reference for both academic and industrial applications in the design of multi-protocol communication infrastructures. Experimental results showed that the system operates stably and rapidly in different protocol combinations. It is concluded that the modular protocol architecture will provide a robust foundation for the sustainable development processes of smart and electric vehicles and for next-generation vehicle architectures. Keywords: CAN, electric vehicles, embedded systems, in-vehicle communication, LIN, modular design, multi-protocol, multi-protocol, protocol converter, RS485, STM32, UART