STM32L4实时时钟模块(RTC)介绍.pdf

STM32L4 Real-Time Clock (RTC) RTC Features (1/2) 63 • Ultra-low power battery supply current. • Calendar with Sub seconds, seconds, minutes, hours, week day, date, month, and year. • Daylight saving compensation programmable by software • Two programmable alarms with interrupt function. The alarms can be triggered by any combination of the calendar fields. • A periodic flag triggering an automatic wakeup interrupt. This flag is issued by a 16-bit auto-reload timer with programmable resolution. This timer is also called ‘wakeup timer’. • A second clock source (50 or 60Hz) can be used to update the calendar. • Maskable interrupts/events: • Alarm A, Alarm B, Wakeup interrupt, Time-stamp, Tamper detection • Digital calibration circuit (periodic counter correction) to achieve 0.95 ppm accuracy • Time-stamp function for event saving with sub second precision (1 event) • 32 backup registers (128 bytes) which are reset when an tamper detection event occurs. Presentation Title 02/07/2015 RTC Features (2/2) 64 • Alternate function outputs: • RTC_CALIB: 512 Hz or 1Hz clock output (with an LSE frequency of 32.768 kHz). It is routed to the device RTC_OUT output. • RTC_ALARM: Alarm A, B flag output. It is routed to the device RTC_OUT output. • Alternate function inputs: • RTC_TAMP1: tamper1 event detection. • RTC_TAMP2: tamper2 event detection. • RTC_TAMP3: tamper3 event detection. • RTC_TS: timestamp event detection. • RTC_REFIN: reference clock input. • The RTC clock source could be any of the following three: • LSE oscillator clock : available in all LP modes + VBAT