GigaDevice Semiconductor GD32F3x0 - Real-Time Clock (RTC); Overview; Characteristics

GD32F3x0 User Manual
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15. Real-time clock (RTC)
15.1. Overview
The RTC provides a time which includes hour / minute / second / sub-second and a calendar
including year / month / day / week day. The time and calendar are expressed in BCD code
except sub-second. Sub-second is expressed in binary code. Hour adjustment for daylight
saving time. Working in power saving mode and smart wakeup is software configurable.
Support improving the calendar accuracy using extern accurate low frequency clock.
15.2. Characteristics
 Daylight saving compensation supported by software.
 External high-accurate low frequency (50Hz or 60Hz) clock used to achieve higher
calendar accuracy performed by reference clock detection option function.
 Atomic clock adjustment (max adjustment accuracy is 0.95PPM) for calendar calibration
performed by digital calibration function.
 Sub-second adjustment by shift function.
 Time-stamp function for saving event time.
 Two Tamper sources can be chosen and tamper type is configurable.
 Programmable calendar and one field maskable alarms.
 Maskable interrupt source:
– Alarm 0
– Time-stamp detection
– Tamper detection
 Five 32-bit (20 bytes total) universal backup registers which can keep data under power
saving mode. Backup register will be reset if tamper event detected.