In time-sensitive embedded systems, precise and persistent timekeeping is essential for ensuring deterministic behavior, especially in applications such as industrial automation, smart monitoring, and data logging. This research investigates the integration and role of Real-Time Clock (RTC) subsystems within the BeagleBone Black (BBB) platform, a popular ARM-based development board for embedded Linux applications. The primary objective of this study is to evaluate the operational efficiency and system-level impact of RTC modules—both onboard and externally interfaced—on maintaining accurate time in various operational scenarios, including power outages, system reboots, and alarm-triggered events. To achieve this, a high-precision external RTC (DS3231) was interfaced with the BBB via the I2C protocol. A custom Linux kernel driver was designed and integrated into the existing RTC subsystem, enabling low-level communication with the hardware and providing user-space access through standard interfaces. The methodology included device tree configuration, I2C bus initialization, interrupt handling for alarm functionality, and rigorous testing under different power and operational states. The experimental results demonstrate that the external RTC significantly enhances timekeeping reliability and minimizes drift compared to the onboard RTC. Additionally, the system's ability to maintain time across power failures and trigger scheduled tasks validates the critical role of RTC in enabling deterministic system responses. The research offers valuable insights into embedded time synchronization strategies and serves as a practical reference for implementing RTC-based functionalities in Linux-based embedded platforms. These findings contribute toward developing robust, fault-tolerant embedded systems with reliable temporal accuracy.

Keywords: BeagleBone Black, RTC, Linux Device Driver, Timekeeping, Embedded Systems, I²C.