The STM32F051x family RTC应用-The STM32F051x family incorporates the high-performance ARM Cortex.-M0 32-bit RISC

core operating at a 48 MHz frequency, high-speed embedded memories (Flash memory up

to 64 Kbytes and SRAM up to 8 Kbytes), and an extensive range of enhanced peripherals

and I/Os. All devices offer standard communication interfaces (up to two I2Cs, two SPIs, one

I2S, one HDMI CEC, and up to two USARTs), one 12-bit ADC, one 12-bit DAC, up to five

general-purpose 16-bit timers, a 32-bit timer and an advanced-control PWM timer.