The STM32F103Rx from STMicroelectronics is a Space Qualified Microcontroller with Clock Rate 32 kHz to 16 MHz, Operating Frequency 72 MHz, Internal RAM Memory SRAM : 20 kB, Flash Memory 64 to 128 kB, Supply Voltage 2 to 3.6 V. Tags: Surface Mount. More details for STM32F103Rx can be seen below.