STM32 F103 C6 Bluepill STM32F103C6T6 ARM Cortex STM 32 Bit Nano Micro

Features
Microcontroller: STM32F103C6T6
ARM® 32-bit Cortex® -M3 CPU
72 MHz max CPU frequency
Voltage from 2 V to 3.6 V
32 KB Flash
10 KB SRAM
Communication: I2C, SPI, UART, CAN, USB
GPIO with external interrupt capability
Up to 6 Timers (2 x 16-bit timers, 1 x PWM timer, 2 x watchdog timers and a SysTick timer)
RTC