The GD32F105RBT6 is an ARM Cortex-M3 microcontroller manufactured by Gigadevice. This microcontroller is a 64-pin LQFP, which stands for Low-Profile Quad Flat Pack. It has a CPU frequency of 72 MHz, 8kB SRAM, 256kB Flash memory, and supports up to 8 USARTs for serial communication. It features 21 GPIOs (General Purpose Input/Output) pins and a variety of built-in peripherals, including 2xCAN, 3xI2C, 4xSPI, 4xADC, 3xIWDG, and 2xDAC. It is ideal for embedded systems, motor control, security systems, and digital signal processing applications. It is also compliant with ISO/IEC 18092 and ISO/IEC 14443 Type A standards.