The STM32F101x4 and STM32F101x6 Low-density access line family incorporates the high-performance ARM Cortex™-M3 32-bit RISC core operating at a 36 MHz frequency, high-speed embedded memories (Flash memory of 16 to 32 Kbytes and SRAM of 4 to 6 Kbytes), and an extensive range of enhanced peripherals and I/Os connected to two APB buses. All devices offer standard communication interfaces (one I2C, one SPI, and two USARTs), one 12-bit ADC and up to two general-purpose 16-bit timers.