STM32F103C8T6 ARM STM32 Minimum System Development Board Module For arduino Model: STM32F103C8T6. Core: ARM 32 Cortex-M3 CPU. 72MHz work frequency. 64K flash memory, 20K SRAM. 2.0-3.6V power, I/O. Reset(POR/PDR). 4-16MHz crystal. On-board Mini USB interface, you can give the board power supply and USB communication. Size:5.3cm x 2.2cm.