What this part is and where it fits
The STM32F105RCT6V is a 32-bit ARM Cortex-M3 microcontroller from STMicroelectronics' STM32F1 Connectivity line. It runs at 72 MHz and carries 256 KB of Flash program memory with 64 KB of SRAM.
72 MHz core — what it means for the control loop
At 72 MHz the Cortex-M3 executes single-cycle multiply and hardware divide. The 51 GPIOs, 16-channel 12-bit ADC, and dual 12-bit DAC let you close analog and digital control loops without external glue logic.
Connectivity mix — USB OTG and CAN
The STM32F105RCT6V carries USB OTG full-speed and two CAN 2.0B interfaces alongside I²C, SPI, UART/USART, IrDA, and LIN.