Introduction In the rapidly evolving world of embedded systems, few microcontrollers have achieved the iconic status of the STM32F103 . Often referred to as the "Blue Pill" (due to the popular blue development board), this ARM Cortex-M3 based microcontroller has become a cornerstone for hobbyists, students, and professional engineers. Whether you are building a simple LED blinker or a complex motor control system for industrial automation, the STM32F103 offers a perfect blend of performance, power efficiency, and affordability.