STM32 ARM Minimum System Development Board Module for Arduino(Type B)

STM32F103C6T6

Specification:

Onboard Mini USB interface, you can give the board power supply and USB communication.
72MHz work frequency
64K flash memory, 20K SRAM
2.0-3.6V power, I/O
Reset(POR/PDR)
4-16MHz crystal
32 kHz oscillator for RTC with calibration
Up to 2 x I2C interfaces (SMBus/PMBus)
Up to 3 USARTs (ISO 7816 interface, LIN, IrDA capability, modem control)
Up to 2 SPIs (18 Mbit/s)
CAN interface (2.0B Active)